Added Java code.

76 files changed, 4903 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
index 0f182a0..7d84a36 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,3 +4,11 @@
 *.jar
 *.war
 *.ear
+
+# Maven and Eclipse directories
+/target
+/.settings
+
+# Eclipse files
+.classpath
+.project
diff --git a/README.md b/README.md
index c37837f..8222fea 100644
--- a/README.md
+++ b/README.md
@@ -5,4 +5,6 @@ This is a reference implementation of OMTC, an open API Standard for Machine Tra
 
 It is a Java implementation that is Java v1.5 compliant.
 
+Use Maven v3.x to build.
+
 Documentation coming soon.
diff --git a/pom.xml b/pom.xml
new file mode 100644
index 0000000..ee84f46
--- /dev/null
+++ b/pom.xml
@@ -0,0 +1,81 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+
+  <groupId>com.capitati.omtc</groupId>
+  <artifactId>omtc-core</artifactId>
+  <version>1.0</version>
+  <packaging>jar</packaging>
+
+  <name>omtc</name>
+  <url>http://maven.apache.org</url>
+
+  <properties>
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+  </properties>
+
+  <dependencies>
+    <dependency>
+      <groupId>commons-collections</groupId>
+      <artifactId>commons-collections</artifactId>
+      <version>20040616</version>
+      <scope>compile</scope>
+    </dependency>
+
+    <dependency>
+      <groupId>org.apache.commons</groupId>
+      <artifactId>commons-lang3</artifactId>
+      <version>3.1</version>
+      <scope>compile</scope>
+    </dependency>
+
+    <!-- Guava, formerly Google Collections -->
+    <dependency>
+      <groupId>com.google.guava</groupId>
+      <artifactId>guava</artifactId>
+      <version>13.0.1</version>
+      <scope>compile</scope>
+    </dependency>
+
+    <dependency>
+      <groupId>junit</groupId>
+      <artifactId>junit</artifactId>
+      <version>4.10</version>
+      <scope>test</scope>
+    </dependency>
+
+    <dependency>
+      <groupId>org.jmock</groupId>
+      <artifactId>jmock-junit4</artifactId>
+      <version>2.5.1</version>
+      <scope>test</scope>
+    </dependency>
+  </dependencies>
+
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-surefire-plugin</artifactId>
+        <version>2.12</version>
+        <executions>
+          <execution>
+            <id>default-test</id>
+            <phase>test</phase>
+            <goals>
+              <goal>test</goal>
+            </goals>
+            <configuration>
+              <includes>
+                <include>**/*Tests.class</include>
+                <include>**/*Test.class</include>
+              </includes>
+            </configuration>
+          </execution>
+        </executions>
+      </plugin>
+    </plugins>
+  </build>
+</project>
+
diff --git a/src/main/java/com/capitati/omtc/core/commons/IDisposable.java b/src/main/java/com/capitati/omtc/core/commons/IDisposable.java
new file mode 100644
index 0000000..e4bf66e
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/commons/IDisposable.java
@@ -0,0 +1,23 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.commons;
+
+public interface IDisposable {
+  void dispose();
+}
diff --git a/src/main/java/com/capitati/omtc/core/commons/IStoppable.java b/src/main/java/com/capitati/omtc/core/commons/IStoppable.java
new file mode 100644
index 0000000..3e1b1f1
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/commons/IStoppable.java
@@ -0,0 +1,23 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.commons;
+
+public interface IStoppable {
+  void stop();
+}
diff --git a/src/main/java/com/capitati/omtc/core/engine/IComposableEngine.java b/src/main/java/com/capitati/omtc/core/engine/IComposableEngine.java
new file mode 100644
index 0000000..a4cba1b
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/engine/IComposableEngine.java
@@ -0,0 +1,61 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.engine;
+
+import com.capitati.omtc.core.integration.data.IDataExchangeFormatSpecification;
+import com.capitati.omtc.core.scheduling.CompositionTicket;
+import com.capitati.omtc.core.scheduling.IPriority;
+import com.capitati.omtc.core.scheduling.ITicketObserver;
+import com.capitati.omtc.core.session.ISession;
+
+/**
+ * A mixin for composing two engines. Implementers are to mixin this
+ * interface with their {@link com.capitati.omtc.core.engine.IEngine}
+ * implementation.
+ *
+ * @author ian
+ *
+ * @param <V> - the priority's type.
+ */
+public interface IComposableEngine<V> extends ITicketableEngine<V> {
+  /**
+   * Compose two engines. Suppose two engines E<sub>1</sub> and E<sub>2</sub>,
+   * this composition shall produce an engine that is
+   * E<sub>resultant</sub> = E<sub>2</sub>(E<sub>1</sub>(s)).
+   * 
+   * @param session - the invoking session.
+   * @param engine - the other engine to compose, i.e., E<sub>2</sub>.
+   * @param exchangeFormat - the exchange data format that the engines will use
+   * to communicate.
+   * @param resultantEngine - the engine that the composition operation
+   * shall create if successful.
+   * @param priority - the priority of this task.
+   * @param engineObserver - the observer that will be notified on completion
+   * of the task.
+   * @return A {@link com.capitati.omtc.core.scheduling.CompositionTicket} object.
+   * @throws Exception On an error.
+   */
+  CompositionTicket<V> compose(
+      ISession session,
+      IEngine engine,
+      IDataExchangeFormatSpecification exchangeFormat,
+      IEngine resultantEngine,
+      IPriority<V> priority,
+      ITicketObserver<CompositionTicket<V>, V> engineObserver) throws Exception;
+}
diff --git a/src/main/java/com/capitati/omtc/core/engine/IEngine.java b/src/main/java/com/capitati/omtc/core/engine/IEngine.java
new file mode 100644
index 0000000..485cb52
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/engine/IEngine.java
@@ -0,0 +1,42 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.engine;
+
+import com.capitati.omtc.core.resources.IDerivedResource;
+
+/**
+ * A translation engine.
+ *
+ * @author ian
+ */
+public interface IEngine extends IDerivedResource {
+  /**
+   * Retrieve the assigned name for the engine.
+   * 
+   * @return The engine's name.
+   */
+  String getName();
+
+  /**
+   * Retrieve some descriptive free text about the engine.
+   * 
+   * @return The engine's descriptive text.
+   */
+  String getDescription();
+}
diff --git a/src/main/java/com/capitati/omtc/core/engine/IEvaluatableEngine.java b/src/main/java/com/capitati/omtc/core/engine/IEvaluatableEngine.java
new file mode 100644
index 0000000..d1f7452
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/engine/IEvaluatableEngine.java
@@ -0,0 +1,73 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.engine;
+
+import java.util.Set;
+
+import com.capitati.omtc.core.resources.IPrimaryResource;
+import com.capitati.omtc.core.scheduling.EvaluationTicket;
+import com.capitati.omtc.core.scheduling.IPriority;
+import com.capitati.omtc.core.scheduling.ITicketObserver;
+import com.capitati.omtc.core.session.ISession;
+
+/**
+ * A mixin to provide support for evaluating an engine. Implementers are to
+ * mixin this interface with their implementation of
+ * {@link com.capitati.omtc.core.engine.IEngine}.
+ * 
+ * @author ian
+ *
+ * @param <V> - the task's priority type.
+ */
+public interface IEvaluatableEngine<V> extends ITicketableEngine<V> {
+  /**
+   * Evaluate an engine. On completion of this the evaluation task the
+   * implementation should store the scores calculated so that
+   * {@link com.capitati.omtc.core.engine.IEvaluatableEngine#getScores} can
+   * return appropriate data.
+   *
+   * @param session - the invoking session.
+   * @param evaluationResources - the primary resources to use for evaluation.
+   * @param priority - the priority of the task.
+   * @param engineObserver - the observer to listen for evaluation completion.
+   * @return An evaluation ticket.
+   * @throws Exception On an error.
+   */
+  EvaluationTicket<V> evaluate(
+      ISession session,
+      Set<IPrimaryResource> evaluationResources,
+      IPriority<V> priority,
+      ITicketObserver<EvaluationTicket<V>, V> engineObserver) throws Exception;
+
+  /**
+   * Retrieve any scores associated with an engine. The method
+   * {@link com.capitati.omtc.core.engine.IEvaluatableEngine#evaluate}
+   * should provided information, internally, to enable this method to
+   * return the scores calculated during a call, and subsequent calls, to
+   * {@link com.capitati.omtc.core.engine.IEvaluatableEngine#evaluate}.
+   * Without running an evaluation, it is implementation defined whether,this
+   * method returns an empty set.
+   *
+   * @param session - the invoking session.
+   * @return A {@link java.util.Set} of
+   * {@link com.capitati.omtc.core.engine.IScore} objects the represent the
+   * scores from an evaluation.
+   */
+  Set<IScore> getScores(ISession session) throws Exception;
+}
diff --git a/src/main/java/com/capitati/omtc/core/engine/IParameterisableEngine.java b/src/main/java/com/capitati/omtc/core/engine/IParameterisableEngine.java
new file mode 100644
index 0000000..a412a74
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/engine/IParameterisableEngine.java
@@ -0,0 +1,54 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.engine;
+
+import java.util.Map;
+
+import com.capitati.omtc.core.session.ISession;
+
+/**
+ * A mixin to provide support for a parameterisable engine. Parameters are keyed
+ * with a type K whose type shall be P. Methods are to be implemented that
+ * fetch engine parameters and allow updating of parameters.
+ *
+ * @author ian
+ *
+ * @param <K> - the type of the parameter key.
+ * @param <P> - the type of the parameter value.
+ */
+public interface IParameterisableEngine<K, P> {
+  /**
+   * Return the current parameters for an engine.
+   * 
+   * @param session - the invoking session.
+   * 
+   * @return A map of parameters.
+   * @throws Exception On an error.
+   */
+  Map<K, P> getParamters(ISession session) throws Exception;
+
+  /**
+   * Update the current parameters with the parameters provided. 
+   *
+   * @param session - the invoking session.
+   * @param newParameters - the parameters used to update the current ones.
+   * @throws Exception On an error.
+   */
+  void updateParameters(ISession session, Map<K, P> newParameters) throws Exception;
+}
diff --git a/src/main/java/com/capitati/omtc/core/engine/IQueryableEngine.java b/src/main/java/com/capitati/omtc/core/engine/IQueryableEngine.java
new file mode 100644
index 0000000..f2ec9ab
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/engine/IQueryableEngine.java
@@ -0,0 +1,51 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.engine;
+
+import com.capitati.omtc.core.scheduling.IPriority;
+import com.capitati.omtc.core.scheduling.ITicketObserver;
+import com.capitati.omtc.core.scheduling.QueryTicket;
+import com.capitati.omtc.core.session.ISession;
+
+/**
+ * A mixin to add support to querying an engine. A single source sentence
+ * is sent to an engine which can be used, amongst other things, for testing.
+ * Implementers should mixin this interface with their
+ * {@link com.capitati.omtc.core.engine.IEngine} implementations.
+ *
+ * @author ian
+ *
+ * @param <V> - the type of the task's priority value.
+ */
+public interface IQueryableEngine<V> extends ITicketableEngine<V> {
+  /**
+   * Send a source sentence to an engine.
+   *
+   * @param session - the invoking session.
+   * @param sourceSentence - the source sentence to send to the engine
+   * @param engineObserver - an observer to be notified of completion.
+   * @return A query ticket object.
+   * @throws Exception On an error.
+   */
+  QueryTicket<V> query(
+      ISession session,
+      String sourceSentence,
+      IPriority<V> priority,
+      ITicketObserver<QueryTicket<V>, V> ticketObserver) throws Exception;
+}
diff --git a/src/main/java/com/capitati/omtc/core/engine/IRetrainableEngine.java b/src/main/java/com/capitati/omtc/core/engine/IRetrainableEngine.java
new file mode 100644
index 0000000..7202cf9
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/engine/IRetrainableEngine.java
@@ -0,0 +1,55 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.engine;
+
+import java.util.Set;
+
+import com.capitati.omtc.core.resources.IPrimaryResource;
+import com.capitati.omtc.core.scheduling.IPriority;
+import com.capitati.omtc.core.scheduling.ITicketObserver;
+import com.capitati.omtc.core.scheduling.TrainingTicket;
+import com.capitati.omtc.core.session.ISession;
+
+/**
+ * A mixin to provide retraining capability if the engine implementation
+ * can support it.
+ *
+ * @author ian
+ *
+ * @param <V> - the type of the priority value.
+ */
+public interface IRetrainableEngine<V> extends ITicketableEngine<V> {
+  /**
+   * Retain an engine using a set of primary resources.
+   *
+   * @param session - the invoking session.
+   * @param retrainingResources - a {@link java.util.Set} of
+   * {@link com.capitati.omtc.core.resources.IPrimaryResource} objects that
+   * shall be used to retain the engine.
+   * @param priority - the priority of the retraining task.
+   * @param engineObserver - the observer listening for the retrain to complete.
+   * @return A training ticket.
+   * @throws Exception On an error.
+   */
+  TrainingTicket<V> retrain(
+      ISession session,
+      Set<IPrimaryResource> retrainingResources,
+      IPriority<V> priority,
+      ITicketObserver<TrainingTicket<V>, V> engineObserver) throws Exception;
+}
diff --git a/src/main/java/com/capitati/omtc/core/engine/IScore.java b/src/main/java/com/capitati/omtc/core/engine/IScore.java
new file mode 100644
index 0000000..e9a6868
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/engine/IScore.java
@@ -0,0 +1,52 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.engine;
+
+import java.util.Set;
+
+import com.capitati.omtc.core.resources.IPrimaryResource;
+
+/**
+ * A representation of a single evaluation score.
+ *
+ * @author ian
+ */
+public interface IScore {
+  /**
+   * Retrieve the score scheme. Or, which algorithm was used to generate the
+   * score.
+   * 
+   * @return A scoring scheme description object.
+   */
+  IScoreScheme getScheme();
+
+  /**
+   * The evaluated score.
+   * 
+   * @return The score for the scheme used.
+   */
+  double getScore();
+
+  /**
+   * Retrieve the resources that generated the score.
+   *
+   * @return A {@link java.util.Set} of primary resource objects.
+   */
+  Set<IPrimaryResource> getResources();
+}
diff --git a/src/main/java/com/capitati/omtc/core/engine/IScoreScheme.java b/src/main/java/com/capitati/omtc/core/engine/IScoreScheme.java
new file mode 100644
index 0000000..5f6ec6a
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/engine/IScoreScheme.java
@@ -0,0 +1,40 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.engine;
+
+/**
+ * The name and descriptive text for a scoring scheme.
+ *
+ * @author ian
+ */
+public interface IScoreScheme {
+  /**
+   * Retrieve the name of a scoring scheme.
+   * 
+   * @return The name of the scheme.
+   */
+  String getName();
+
+  /**
+   * Retrieve the descriptive text for a scoring scheme.
+   *
+   * @return The descriptive free text.
+   */
+  String getDescription();
+}
diff --git a/src/main/java/com/capitati/omtc/core/engine/ITestableEngine.java b/src/main/java/com/capitati/omtc/core/engine/ITestableEngine.java
new file mode 100644
index 0000000..7d488e8
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/engine/ITestableEngine.java
@@ -0,0 +1,41 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.engine;
+
+import java.util.Set;
+
+import com.capitati.omtc.core.resources.IPrimaryResource;
+import com.capitati.omtc.core.scheduling.IPriority;
+import com.capitati.omtc.core.scheduling.ITicketObserver;
+import com.capitati.omtc.core.scheduling.TestingTicket;
+import com.capitati.omtc.core.session.ISession;
+
+/**
+ * 
+ * @author ian
+ *
+ * @param <P>
+ */
+public interface ITestableEngine<V> extends ITicketableEngine<V> {
+  TestingTicket<V> test(
+      ISession session,
+      Set<IPrimaryResource> testingResources,
+      IPriority<V> priority,
+      ITicketObserver<TestingTicket<V>, V> engineObserver) throws Exception;
+}
diff --git a/src/main/java/com/capitati/omtc/core/engine/ITicketableEngine.java b/src/main/java/com/capitati/omtc/core/engine/ITicketableEngine.java
new file mode 100644
index 0000000..1001a2b
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/engine/ITicketableEngine.java
@@ -0,0 +1,43 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.engine;
+
+import java.util.Set;
+
+import com.capitati.omtc.core.scheduling.EngineTicket;
+import com.capitati.omtc.core.session.ISession;
+import com.google.common.base.Predicate;
+
+/**
+ * A mixin that provides support for engines that, on submiting tasks, return
+ * task tickets. This inferface should be used with the implementer's
+ * {@link com.capitati.omtc.core.engine.IEngine} concrete classes to 
+ * provide a mechanism to return <em>running</em> tickets. It is the
+ * responsibility of the concrete class to manage the appropriate collection
+ * of dispensed tickets.
+ *
+ * @author ian
+ *
+ * @param <V> - the type of the priority's value.
+ */
+public interface ITicketableEngine<V> {
+  Set<EngineTicket<V>> retrieveTickets(
+      ISession session, Predicate<EngineTicket<V>> filter)
+  throws Exception;
+}
diff --git a/src/main/java/com/capitati/omtc/core/engine/ITrainableEngine.java b/src/main/java/com/capitati/omtc/core/engine/ITrainableEngine.java
new file mode 100644
index 0000000..199ae41
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/engine/ITrainableEngine.java
@@ -0,0 +1,55 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.engine;
+
+import java.util.Set;
+
+import com.capitati.omtc.core.resources.IPrimaryResource;
+import com.capitati.omtc.core.scheduling.IPriority;
+import com.capitati.omtc.core.scheduling.ITicketObserver;
+import com.capitati.omtc.core.scheduling.TrainingTicket;
+import com.capitati.omtc.core.session.ISession;
+
+/**
+ * A mixin to offer support for training engines. Implementers of the
+ * {@link com.capitati.omtc.core.engine.IEngine} interface should mixin this
+ * interface to their concrete classes.
+ *
+ * @author ian
+ *
+ * @param <V> - the type of the priority's value.
+ */
+public interface ITrainableEngine<V> extends ITicketableEngine<V> {
+  /**
+   * Train an engine.
+   *
+   * @param session - the invoking session.
+   * @param trainingResources - a {@link java.util.Set} of primary resources
+   * used to train the engine.
+   * @param priority - the priority of the train task.
+   * @param engineObserver - the observer that listens for task completion.
+   * @return A training ticket.
+   * @throws Exception On an error.
+   */
+  TrainingTicket<V> train(
+      ISession session,
+      Set<IPrimaryResource> trainingResources,
+      IPriority<V> priority,
+      ITicketObserver<TrainingTicket<V>, V> engineObserver) throws Exception;
+}
diff --git a/src/main/java/com/capitati/omtc/core/engine/IUpdatableEngine.java b/src/main/java/com/capitati/omtc/core/engine/IUpdatableEngine.java
new file mode 100644
index 0000000..dd111ee
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/engine/IUpdatableEngine.java
@@ -0,0 +1,63 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.engine;
+
+import com.capitati.omtc.core.scheduling.IPriority;
+import com.capitati.omtc.core.scheduling.ITicketObserver;
+import com.capitati.omtc.core.scheduling.UpdateTicket;
+import com.capitati.omtc.core.session.ISession;
+
+/**
+ * A mixin for engines that support updating. The update operation is ticketed
+ * since the operation be computationally expensive. The update operation
+ * shall typically mutate the engine. It is recommended that the engine,
+ * during an update operation, is mutually excluded.
+ *
+ * @author ian
+ *
+ * @param <V> - the type of the priority's value.
+ */
+public interface IUpdatableEngine<V, P> extends ITicketableEngine<V> {
+  /**
+   * Update an engine's parameters using key-value pairs specified in a
+   * {@link java.util.Map} object.
+   *
+   * @param session - the invoking session.
+   * @param parameters - the update parameters for the engine.
+   * @param priority - the task's priority.
+   * @param engineObserver - the observer listening for the starting and
+   * completion of the task.
+   * @return An updating ticket.
+   * @throws Exception On an error.
+   */
+  UpdateTicket<V> updateParameters(
+      ISession session,
+      P parameters,
+      IPriority<V> priority,
+      ITicketObserver<UpdateTicket<V>, V> engineObserver) throws Exception;
+
+  /**
+   * Retrieve the current parameters of the engine.
+   *
+   * @param - the invoking session.
+   * @return An object that holds the engine's current parameters.
+   * @throws Exception On an error.
+   */
+  P getParameters(ISession session) throws Exception;
+}
diff --git a/src/main/java/com/capitati/omtc/core/integration/data/IDataExchangeFormatSpecification.java b/src/main/java/com/capitati/omtc/core/integration/data/IDataExchangeFormatSpecification.java
new file mode 100644
index 0000000..9d8c43a
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/integration/data/IDataExchangeFormatSpecification.java
@@ -0,0 +1,60 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.integration.data;
+
+import com.capitati.omtc.core.negotiation.IVersion;
+
+/**
+ * A description of a data exchange format, specification or standard.
+ * Implementers of this interface shall decide on a unique identifier for
+ * the data exchange format.
+ *
+ * @author ian
+ */
+public interface IDataExchangeFormatSpecification
+extends Comparable<IDataExchangeFormatSpecification> {
+  /**
+   * The short name, probably and acronym, for the format, specification, or
+   * standard.
+   *
+   * @return The short name of the data exchange format.
+   */
+  String getShortName();
+
+  /**
+   * The long name for the format, specification standard.
+   *
+   * @return The long name of the data exchange format.
+   */
+  String getLongName();
+
+  /**
+   * The lowest version of the data exchange format at which the client supports.
+   *
+   * @return The lowest supported version.
+   */
+  IVersion getLowestVersion();
+
+  /**
+   * The highest version of the data exchange format the client supports.
+   *
+   * @return The highest supported version.
+   */
+  IVersion getHighestVersion();
+}
diff --git a/src/main/java/com/capitati/omtc/core/negotiation/Capability.java b/src/main/java/com/capitati/omtc/core/negotiation/Capability.java
new file mode 100644
index 0000000..6d4aeb9
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/negotiation/Capability.java
@@ -0,0 +1,48 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.negotiation;
+
+public enum Capability {
+  INVALID(CapabilityGroup.INVALID),
+  
+  API_VERSION(CapabilityGroup.API),
+  
+  RES_FILE_TMX(CapabilityGroup.RESOURCE),
+  RES_FILE_TBX(CapabilityGroup.RESOURCE),
+  RES_FILE_UTX(CapabilityGroup.RESOURCE),
+  RES_FILE_SRX(CapabilityGroup.RESOURCE),
+  RES_FILE_ITS(CapabilityGroup.RESOURCE),
+  RES_FILE_XLIFF(CapabilityGroup.RESOURCE),
+  RES_FILE_TTX(CapabilityGroup.RESOURCE),
+  
+  FET_RES_UPLOAD(CapabilityGroup.FEATURE),
+  FET_RES_DOWNLOAD(CapabilityGroup.FEATURE),
+  
+  PRE_REQ_PAYMENT(CapabilityGroup.PREREQUISITE);
+
+  private CapabilityGroup group;
+
+  private Capability(final CapabilityGroup theGroup) {
+    group = theGroup;
+  }
+
+  public CapabilityGroup getGroup() {
+    return group;
+  }
+}
diff --git a/src/main/java/com/capitati/omtc/core/negotiation/CapabilityGroup.java b/src/main/java/com/capitati/omtc/core/negotiation/CapabilityGroup.java
new file mode 100644
index 0000000..22c9eb1
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/negotiation/CapabilityGroup.java
@@ -0,0 +1,37 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.negotiation;
+
+public enum CapabilityGroup {
+  INVALID("INVALID"),
+  API("API"),
+  RESOURCE("Resource"),
+  FEATURE("Feature"),
+  PREREQUISITE("Prerequisite");
+
+  final private String name;
+  
+  private CapabilityGroup(final String theName) {
+    name = theName;
+  }
+  
+  public String toString() {
+    return name;
+  }
+}
diff --git a/src/main/java/com/capitati/omtc/core/negotiation/IAPICapability.java b/src/main/java/com/capitati/omtc/core/negotiation/IAPICapability.java
new file mode 100644
index 0000000..0c9a41b
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/negotiation/IAPICapability.java
@@ -0,0 +1,34 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.negotiation;
+
+/**
+ * The semantic version capability of the API.
+ *
+ * @author ian
+ */
+public interface IAPICapability extends ICapability {
+  /**
+   * Retrieve the semantic version of the API.
+   * 
+   * @return An instance of {@link com.capitati.omtc.core.negotiation.ISemanticVersion}
+   * which represents the semantic version of the API.
+   */
+  ISemanticVersion getVersion();
+}
diff --git a/src/main/java/com/capitati/omtc/core/negotiation/ICapability.java b/src/main/java/com/capitati/omtc/core/negotiation/ICapability.java
new file mode 100644
index 0000000..0f1c6ab
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/negotiation/ICapability.java
@@ -0,0 +1,34 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.negotiation;
+
+/**
+ * The base capability interface. Specifies only the unique aspect of a
+ * capability.  
+ *
+ * @author ian
+ */
+public interface ICapability {
+  /**
+   * Get the unique capability
+   *
+   * @return the capability's unique name
+   */
+  Capability getName();
+}
diff --git a/src/main/java/com/capitati/omtc/core/negotiation/IClientCapabilityRequest.java b/src/main/java/com/capitati/omtc/core/negotiation/IClientCapabilityRequest.java
new file mode 100644
index 0000000..2e834be
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/negotiation/IClientCapabilityRequest.java
@@ -0,0 +1,48 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.negotiation;
+
+import java.util.Set;
+
+
+/**
+ * A description of the client's capabilities.
+ *
+ * @author ian
+ */
+public interface IClientCapabilityRequest {
+  /**
+   * Implementers shall return the client's supported API version capability.
+   *
+   * @return A {@link com.capitati.omtc.core.negotiation.IAPICapability}
+   * objects which represent the client's supported API version.
+   */
+  IAPICapability getVersionCapability();
+
+  /**
+   * Implementers shall return a set of the
+   * {@link com.capitati.omtc.core.negotiation.IResourceCapability} objects
+   * which shall represent the resource kinds which it expects the service
+   * to support.
+   *
+   * @return A set of {@link com.capitati.omtc.core.negotiation.IResourceCapability}
+   * objects.
+   */
+  Set<IResourceCapability> getResourceCapabilities();
+}
diff --git a/src/main/java/com/capitati/omtc/core/negotiation/IClientCapabilityResponse.java b/src/main/java/com/capitati/omtc/core/negotiation/IClientCapabilityResponse.java
new file mode 100644
index 0000000..0bb74c5
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/negotiation/IClientCapabilityResponse.java
@@ -0,0 +1,63 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.negotiation;
+
+import java.util.Set;
+
+/**
+ * The response to a client negotiation.
+ *
+ * @author ian
+ */
+public interface IClientCapabilityResponse {
+  /**
+   * Does the service support the client's API revision. If this method returns
+   * false then the service should send the response back to the client and
+   * disconnect the session.
+   *
+   * @return True if the client's API is supported. Otherwise, returns false.
+   */
+  boolean isClientAPISupported();
+
+  /**
+   * The collection of data exchange formats that the service does not support
+   * but the client does. If the set of service supported data exchange formats
+   * is <em>S</em>, and the client supported data exchange formats is <em>C</em>
+   * then the returned collection shall be <em>C - S</em>. This is based, firstly,
+   * on the capability, and then the resource capability's version range.
+   * <p>
+   * When the client receives this set it needs to make a decision whether to
+   * continue with its session. For example, if all of the client's supported
+   * exchange formats are returned here then it is pointless continuing with
+   * the session. The service does not "talk" any of client's supported formats.
+   *
+   * @return A set of
+   * {@link com.capitati.omtc.core.negotiation.IResourceCapability}
+   * objects that the client supports but the service does not.
+   */
+  Set<IResourceCapability> getUnsupportedResourceCapabilities();
+
+  /**
+   * The supported feature capabilities of the service.
+   *
+   * @return A set of {@link com.capitati.omtc.core.negotiation.IFeatureCapability}
+   * objects.
+   */
+  Set<IFeatureCapability> getFeatureCapabilities();
+}
diff --git a/src/main/java/com/capitati/omtc/core/negotiation/IFeatureCapability.java b/src/main/java/com/capitati/omtc/core/negotiation/IFeatureCapability.java
new file mode 100644
index 0000000..25f3916
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/negotiation/IFeatureCapability.java
@@ -0,0 +1,36 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.negotiation;
+
+import java.util.Set;
+
+/**
+ * Implementations of this interface specify a feature capability.
+ *
+ * @author ian
+ */
+public interface IFeatureCapability extends ICapability {
+  /**
+   * Implementers shall return the set of prerequisites for this feature.
+   *
+   * @return A set of {@link com.capitati.omtc.core.negotiation.IPrerequisiteCapability}
+   * objects.
+   */
+  Set<IPrerequisiteCapability> getPrerequisiteCapabilities();
+}
diff --git a/src/main/java/com/capitati/omtc/core/negotiation/INegotiator.java b/src/main/java/com/capitati/omtc/core/negotiation/INegotiator.java
new file mode 100644
index 0000000..6bd42d1
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/negotiation/INegotiator.java
@@ -0,0 +1,38 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.negotiation;
+
+/**
+ * The negotiator that determines whether a client's capabilities are
+ * matched with the server's.
+ *
+ * @author ian
+ *
+ */
+public interface INegotiator {
+  /**
+   * Negotiate a client's capabilities. This method accepts a negotiation request
+   * and constructs a response.
+   * 
+   * @param negotiationRequest - the client's negotiation request.
+   * @return A {@link com.capitati.omtc.core.negotiation.IClientCapabilityResponse}
+   * object that holds the server's response to the client request.
+   */
+  IClientCapabilityResponse negotiate(IClientCapabilityRequest negotiationRequest);
+}
diff --git a/src/main/java/com/capitati/omtc/core/negotiation/IPrerequisiteCapability.java b/src/main/java/com/capitati/omtc/core/negotiation/IPrerequisiteCapability.java
new file mode 100644
index 0000000..b0903b6
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/negotiation/IPrerequisiteCapability.java
@@ -0,0 +1,28 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.negotiation;
+
+/**
+ * Implementations of this interface specify a prerequisite capability.
+ *
+ * @author ian
+ */
+public interface IPrerequisiteCapability extends ICapability {
+
+}
diff --git a/src/main/java/com/capitati/omtc/core/negotiation/IResourceCapability.java b/src/main/java/com/capitati/omtc/core/negotiation/IResourceCapability.java
new file mode 100644
index 0000000..b1f1714
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/negotiation/IResourceCapability.java
@@ -0,0 +1,43 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.negotiation;
+
+/**
+ * Implementations of this interface shall specify the version range
+ * of a specific resource kind, e.g., XLIFF.
+ *
+ * @author ian
+ */
+public interface IResourceCapability extends ICapability {
+  /**
+   * The lowest version of the resource that is supported.
+   * 
+   * @return A string that represents the resource kind's lower supported
+   * version.
+   */
+  String getLowerVersion();
+
+  /**
+   * The highest version of the resource that is supported.
+   * 
+   * @return A string that represents the resource kind's highest supported
+   * version.
+   */
+  String getHigherVersion();
+}
diff --git a/src/main/java/com/capitati/omtc/core/negotiation/ISemanticVersion.java b/src/main/java/com/capitati/omtc/core/negotiation/ISemanticVersion.java
new file mode 100644
index 0000000..9147aec
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/negotiation/ISemanticVersion.java
@@ -0,0 +1,62 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.negotiation;
+
+/**
+ * Semantic versioning.
+ *
+ * @author ian
+ * @see <a href="http://semver.org/">Semantic Versioning 2.0.0-rc.1</a>
+ */
+public interface ISemanticVersion extends Comparable<ISemanticVersion> {
+  /**
+   * Returns the major version number.
+   * 
+   * @return The major version number.
+   */
+  int getMajor();
+
+  /**
+   * Returns the minor version number.
+   * 
+   * @return The minor version number.
+   */
+  int getMinor();
+
+  /**
+   * Return the patch number of the semantic version.
+   * 
+   * @return The patch version number.
+   */
+  int getPatch();
+
+  /**
+   * Returns the parsed pre-release information from the version.
+   * 
+   * @return A string array containing the dot delimited pre-release components.
+   */
+  String[] getPreRelease();
+
+  /**
+   * Returns the parsed build information from the version.
+   *
+   * @return A string array containing the dot delimited build components.
+   */
+  String[] getBuild();
+}
diff --git a/src/main/java/com/capitati/omtc/core/negotiation/IServiceResourceCapability.java b/src/main/java/com/capitati/omtc/core/negotiation/IServiceResourceCapability.java
new file mode 100644
index 0000000..1796878
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/negotiation/IServiceResourceCapability.java
@@ -0,0 +1,35 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.negotiation;
+
+/**
+ * Extends the {@link com.capitati.omtc.core.negotiation.IResourceCapability}
+ * to allow resource capability versions to be compared.
+ *
+ * @author ian
+ */
+public interface IServiceResourceCapability extends IResourceCapability {
+  /**
+   * Comparator method to compare resource kind versions.
+   *
+   * @param otherResourceCapability
+   * @return
+   */
+  int compareVersion(IResourceCapability otherResourceCapability);
+}
diff --git a/src/main/java/com/capitati/omtc/core/negotiation/IVersion.java b/src/main/java/com/capitati/omtc/core/negotiation/IVersion.java
new file mode 100644
index 0000000..7af1de5
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/negotiation/IVersion.java
@@ -0,0 +1,40 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.negotiation;
+
+/**
+ * A base version interface. Major and minor versions.
+ * 
+ * @author ian
+ */
+public interface IVersion extends Comparable<IVersion> {
+  /**
+   * Returns the major version number.
+   * 
+   * @return The major version number.
+   */
+  int getMajor();
+
+  /**
+   * Returns the minor version number.
+   * 
+   * @return The minor version number.
+   */
+  int getMinor();
+}
diff --git a/src/main/java/com/capitati/omtc/core/negotiation/Negotiator.java b/src/main/java/com/capitati/omtc/core/negotiation/Negotiator.java
new file mode 100644
index 0000000..9086fb7
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/negotiation/Negotiator.java
@@ -0,0 +1,141 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.negotiation;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+import org.apache.commons.lang3.tuple.ImmutablePair;
+
+public class Negotiator implements INegotiator {
+  private final ISemanticVersion apiVersion;
+  private final Map<Capability, List<IServiceResourceCapability>> supportedResources;
+  private final Set<IFeatureCapability> featureCapabilities;
+
+  public Negotiator(
+      final String theApiVersion,
+      final Collection<IServiceResourceCapability> theResourceCapabilities,
+      final Collection<IFeatureCapability> theFeatureCapabilities)
+  throws SemanticVersionParseException {
+    super();
+    apiVersion = SemanticVersion.parseVersion(theApiVersion);
+
+    featureCapabilities = (theFeatureCapabilities == null) ?
+        new HashSet<IFeatureCapability>() :
+        new HashSet<IFeatureCapability>(theFeatureCapabilities);
+
+    /*
+     * Group resource capabilities by their unique identifier for possibly
+     * different version of the resource revision.
+     */
+    supportedResources = new HashMap<Capability, List<IServiceResourceCapability>>();
+    if(theResourceCapabilities != null) {
+      for(IServiceResourceCapability resourceCap : theResourceCapabilities) {
+        final Capability capabilityName = resourceCap.getName();
+
+        if(supportedResources.containsKey(capabilityName) == true) {
+          final List<IServiceResourceCapability> yeah =
+              supportedResources.get(capabilityName);
+          yeah.add(resourceCap);
+        } else {
+          final List<IServiceResourceCapability> yeah =
+              new ArrayList<IServiceResourceCapability>();
+          yeah.add(resourceCap);
+          supportedResources.put(capabilityName, yeah);
+        }
+      }
+    }
+  }
+
+  public final IClientCapabilityResponse negotiate(
+      final IClientCapabilityRequest negotiationRequest) {
+    final ISemanticVersion clientAPIVersion =
+        negotiationRequest.getVersionCapability().getVersion();
+    final boolean isClientAPISupported = isClientAPISupported(clientAPIVersion);
+    final Set<IResourceCapability> unsupportedResources =
+        new HashSet<IResourceCapability>();
+
+    /*
+     * Work out which of the clients resource kinds are supported by the
+     * service.
+     */
+    for(IResourceCapability resourceCap :
+      negotiationRequest.getResourceCapabilities()) {
+      final Capability capabilityName = resourceCap.getName();
+
+      /*
+       * First check if the resource kind is supported.
+       */
+      if(supportedResources.containsKey(capabilityName) == true) {
+        boolean supported = false;
+        
+        for(IServiceResourceCapability svcResourceCap :
+          supportedResources.get(capabilityName)) {
+          if(svcResourceCap.compareVersion(resourceCap) == 0) {
+            supported = true;
+          }
+        }
+        
+        if(supported == false) {
+          unsupportedResources.add(resourceCap);
+        }
+      } else {
+        unsupportedResources.add(resourceCap);
+      }
+    }
+
+    return new IClientCapabilityResponse() {
+      public boolean isClientAPISupported() {
+        return isClientAPISupported;
+      }
+      public Set<IResourceCapability> getUnsupportedResourceCapabilities() {
+        return unsupportedResources;
+      }
+      public Set<IFeatureCapability> getFeatureCapabilities() {
+        return featureCapabilities;
+      }
+    };
+  }
+
+  private boolean isClientAPISupported(ISemanticVersion version) {
+    final ImmutablePair<Integer, SemanticVersionComponent> versionComp =
+        SemanticVersionComparator.compare(apiVersion, version);
+    boolean isApiSupported = false;
+
+    switch(versionComp.getRight()) {
+    case PRE_RELEASE_AND_BUILD_VERSION:
+    case PATCH_VERSION:
+    case MINOR_VERSION:
+      isApiSupported = true;
+      break;
+
+    case MAJOR_VERSION:
+    case INVALID:
+      isApiSupported = (versionComp.getLeft() == 0) ? true : false;
+      break;
+    }
+
+    return isApiSupported;
+  }
+}
diff --git a/src/main/java/com/capitati/omtc/core/negotiation/SemanticVersion.java b/src/main/java/com/capitati/omtc/core/negotiation/SemanticVersion.java
new file mode 100644
index 0000000..998f604
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/negotiation/SemanticVersion.java
@@ -0,0 +1,196 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.negotiation;
+
+import java.util.Arrays;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.commons.lang3.StringUtils;
+
+/**
+ * Implementation of semantic versioning.
+ *
+ * @author ian
+ * @see <a href="http://semver.org/">Semantic Versioning 2.0.0-rc.1</a>
+ */
+public class SemanticVersion implements ISemanticVersion {
+  public static final String IDENTIFIER_SEPARATOR = ".";
+  private static final String PRE_RELEASE_SEPARATOR = "-";
+  private static final String BUILD_SEPARATOR = "+";
+  private static final String GROUP_NAME_MAJOR = "major";
+  private static final String GROUP_NAME_MINOR = "minor";
+  private static final String GROUP_NAME_PATCH = "patch";
+  private static final String GROUP_NAME_PRERELEASE = "prerelease";
+  private static final String GROUP_NAME_BUILD = "build";
+  private static final Pattern versionPattern =
+      Pattern.compile(
+          "(?<" + GROUP_NAME_MAJOR + ">\\d+)\\." +
+          "(?<" + GROUP_NAME_MINOR + ">\\d+)\\." +
+          "(?<" + GROUP_NAME_PATCH + ">\\d+)" +
+          "(([" + PRE_RELEASE_SEPARATOR + "](?<" + GROUP_NAME_PRERELEASE + ">[0-9A-Z-.]+))?" +
+          "([" + BUILD_SEPARATOR + "](?<" + GROUP_NAME_BUILD + ">[0-9A-Z-.]+))?)?",
+          Pattern.CASE_INSENSITIVE);
+
+  public static ISemanticVersion parseVersion(final String version)
+  throws SemanticVersionParseException {
+    final Matcher matcher = versionPattern.matcher(version);
+
+    if(matcher.matches() == false) {
+      throw new SemanticVersionParseException(version);
+    }
+
+    final int theMajor = Integer.parseInt(matcher.group(GROUP_NAME_MAJOR));
+    final int theMinor = Integer.parseInt(matcher.group(GROUP_NAME_MINOR));
+    final int thePatch = Integer.parseInt(matcher.group(GROUP_NAME_PATCH));
+    final String thePreRelease = matcher.group(GROUP_NAME_PRERELEASE);
+    final String theBuild = matcher.group(GROUP_NAME_BUILD);
+
+    return new SemanticVersion(
+        theMajor,
+        theMinor,
+        thePatch,
+        thePreRelease,
+        theBuild);
+  }
+
+  private final int major;
+  private final int minor;
+  private final int patch;
+  private final String[] preRelease;
+  private final String[] build;
+
+  public SemanticVersion(
+      final int theMajorVersion,
+      final int theMinorVersion,
+      final int thePatchVersion) {
+    super();
+    if((theMajorVersion < 0) ||
+       (theMinorVersion < 0) ||
+       (thePatchVersion <0)) {
+      throw new IllegalArgumentException(
+          "Major, minor, or patch version cannot be negative.");
+    }
+    major = theMajorVersion;
+    minor = theMinorVersion;
+    patch = thePatchVersion;
+    preRelease = null;
+    build = null;
+  }
+
+  public SemanticVersion(
+      final int theMajorVersion,
+      final int theMinorVersion,
+      final int thePatchVersion,
+      final String thePreRelease,
+      final String theBuild) {
+    super();
+    if((theMajorVersion < 0) ||
+        (theMinorVersion < 0) ||
+        (thePatchVersion <0)) {
+      throw new IllegalArgumentException(
+          "Major, minor, or patch version cannot be negative.");
+    }
+    major = theMajorVersion;
+    minor = theMinorVersion;
+    patch = thePatchVersion;
+    preRelease = (thePreRelease != null) ?
+        thePreRelease.split("[" + IDENTIFIER_SEPARATOR + "]") :
+        null;
+    build = (theBuild != null) ?
+        theBuild.split("[" + IDENTIFIER_SEPARATOR + "]") :
+        null;
+  }
+
+  public int getMajor() {
+    return major;
+  }
+
+  public int getMinor() {
+    return minor;
+  }
+
+  public int getPatch() {
+    return patch;
+  }
+
+  public String[] getPreRelease() {
+    return preRelease;
+  }
+
+  public String[] getBuild() {
+    return build;
+  }
+
+  @Override
+  public int hashCode() {
+    final int prime = 31;
+    int result = 1;
+    result = prime * result + Arrays.hashCode(build);
+    result = prime * result + major;
+    result = prime * result + minor;
+    result = prime * result + patch;
+    result = prime * result + Arrays.hashCode(preRelease);
+    return result;
+  }
+
+  @Override
+  public boolean equals(Object obj) {
+    if(this == obj)
+      return true;
+    if(obj == null)
+      return false;
+    if(getClass() != obj.getClass())
+      return false;
+    SemanticVersion other = (SemanticVersion) obj;
+    if(!Arrays.equals(build, other.build))
+      return false;
+    if(major != other.major)
+      return false;
+    if(minor != other.minor)
+      return false;
+    if(patch != other.patch)
+      return false;
+    if(!Arrays.equals(preRelease, other.preRelease))
+      return false;
+    return true;
+  }
+
+  @Override
+  public String toString() {
+    final StringBuffer repr =
+        new StringBuffer(String.format("%d.%d.%d", major, minor, patch));
+
+    if(preRelease != null) {
+      repr.append(PRE_RELEASE_SEPARATOR);
+      repr.append(StringUtils.join(preRelease, IDENTIFIER_SEPARATOR));
+    }
+    
+    if(build != null) {
+      repr.append(BUILD_SEPARATOR);
+      repr.append(StringUtils.join(build, IDENTIFIER_SEPARATOR));
+    }
+
+    return repr.toString();
+  }
+
+  public int compareTo(final ISemanticVersion theOtherVersion) {
+    return SemanticVersionComparator.compare(this, theOtherVersion).getLeft();
+  }
+}
diff --git a/src/main/java/com/capitati/omtc/core/negotiation/SemanticVersionComparator.java b/src/main/java/com/capitati/omtc/core/negotiation/SemanticVersionComparator.java
new file mode 100644
index 0000000..017d675
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/negotiation/SemanticVersionComparator.java
@@ -0,0 +1,223 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.negotiation;
+
+import java.util.Iterator;
+import java.util.NoSuchElementException;
+
+import org.apache.commons.collections.iterators.ArrayIterator;
+import org.apache.commons.lang3.tuple.ImmutablePair;
+
+/**
+ * A comparator for two semantic versions.
+ *
+ * @author ian
+ * @see <a href="http://semver.org/">Semantic Versioning 2.0.0-rc.1</a> for
+ * the specification on how this comparator operates.
+ */
+public class SemanticVersionComparator {
+  public static final ImmutablePair<Integer, SemanticVersionComponent> compare(
+      final ISemanticVersion verOne,
+      final ISemanticVersion verTwo) {
+    if(verOne.equals(verTwo) == true) {
+      return new ImmutablePair<Integer, SemanticVersionComponent>(
+          0, SemanticVersionComponent.INVALID);
+    }
+
+    if(verOne.getMajor() == verTwo.getMajor()) {
+      if(verOne.getMinor() == verTwo.getMinor()) {
+        if(verOne.getPatch() == verTwo.getPatch()) {
+          /*
+           * Compare the pre-release components.
+           */
+          final ImmutablePair<Integer, Boolean> preReleaseCompResult =
+              compareArray(verOne.getPreRelease(), verTwo.getPreRelease());
+          /*
+           * Compare the build components.
+           */
+          final ImmutablePair<Integer, Boolean> buildCompResult =
+              compareArray(verOne.getBuild(), verTwo.getBuild());
+
+          /*
+           * Unpack the comparison values.
+           */
+          final int prc = preReleaseCompResult.getLeft();
+          final int bc = buildCompResult.getLeft();
+          
+          if((preReleaseCompResult.getRight() == true) &&
+             (buildCompResult.getRight() == true)) {
+            /*
+             * There was at most one pre-release component, and at most one
+             * build component in both versions.
+             */
+            if((Math.abs(prc) == 1) && (Math.abs(bc) == 1)) {
+              return new ImmutablePair<Integer, SemanticVersionComponent>(
+                  (Math.signum((float )prc) == 1.0) ? -1 : 1,
+                  SemanticVersionComponent.PRE_RELEASE_AND_BUILD_VERSION);
+            } else if((Math.abs(prc) == 1) && (bc == 0)) {
+              return new ImmutablePair<Integer, SemanticVersionComponent>(
+                  (Math.signum((float )prc) == 1.0) ? -1 : 1,
+                  SemanticVersionComponent.PRE_RELEASE_AND_BUILD_VERSION);
+            }
+            
+            return new ImmutablePair<Integer, SemanticVersionComponent>(
+                bc, SemanticVersionComponent.PRE_RELEASE_AND_BUILD_VERSION);
+          } else if((preReleaseCompResult.getRight() == true) &&
+              (buildCompResult.getRight() == false)) {
+            /*
+             * One of the versions had a null pre-release.
+             */
+            return new ImmutablePair<Integer, SemanticVersionComponent>(
+                bc, SemanticVersionComponent.PRE_RELEASE_AND_BUILD_VERSION);
+          }
+
+          /*
+           * Either one of the version has a null build or both versions where
+           * fully specified.
+           */
+          return new ImmutablePair<Integer, SemanticVersionComponent>(
+              (Math.abs(prc) == 1) ? prc : bc,
+              SemanticVersionComponent.PRE_RELEASE_AND_BUILD_VERSION);
+        } else {
+          return new ImmutablePair<Integer, SemanticVersionComponent>(
+              verOne.getPatch() - verTwo.getPatch(),
+              SemanticVersionComponent.PATCH_VERSION);
+        }
+      } else {
+        return new ImmutablePair<Integer, SemanticVersionComponent>(
+            verOne.getMinor() - verTwo.getMinor(),
+            SemanticVersionComponent.MINOR_VERSION);
+      }
+    }
+
+    return new ImmutablePair<Integer, SemanticVersionComponent>(
+        verOne.getMajor() - verTwo.getMajor(),
+        SemanticVersionComponent.MAJOR_VERSION);
+  }
+
+  /**
+   * Lexically compare the components of two string arrays.
+   *
+   * @param one - First string array.
+   * @param two - The array that is compared to one.
+   * @return If one array is determined to be lexically less than two then
+   * -1 is returned. If one is determined to be lexically greater then two then
+   * 1 is returned. Otherwise, 0 is returned.
+   */
+  private static ImmutablePair<Integer, Boolean> compareArray(
+      final String[] one,
+      final String[] two) {
+    if((one == null) && (two == null)) {
+      return new ImmutablePair<Integer, Boolean>(0, true);
+    }
+
+    if((one == null) && (two != null)) {
+      return new ImmutablePair<Integer, Boolean>(-1, true);
+    }
+
+    if((one != null) && (two == null)) {
+      return new ImmutablePair<Integer, Boolean>(1, true);
+    }
+
+    @SuppressWarnings("unchecked")
+    final Iterator<String> oneIterator = new ArrayIterator(one);
+    @SuppressWarnings("unchecked")
+    final Iterator<String> twoIterator = new ArrayIterator(two);
+    String oneComp = null;
+    String twoComp = null;
+    int comp = 0;
+
+    while(true) {
+      try {
+        oneComp = oneIterator.next();
+      } catch(final NoSuchElementException ex) {
+        oneComp = null;
+      }
+
+      try {
+        twoComp = twoIterator.next();
+      } catch(final NoSuchElementException ex) {
+        twoComp = null;
+      }
+
+      if((oneComp == null) && (twoComp == null)) {
+        break;
+      }
+
+      comp = componentCompare(oneComp, twoComp);
+      if(comp != 0) {
+        break;
+      }
+    }
+
+    return new ImmutablePair<Integer, Boolean>(comp, false);
+  }
+
+  /**
+   * Compare two components from the pre-release and build string arrays as
+   * detailed in the Semantic Versioning 2.0.0-rc.1 specification.
+   * 
+   * @param oneComp - first value.
+   * @param twoComp - second value.
+   * @return If first value is determined to be less than the second value then
+   * return -1. If one value is determined to be greater than the second value
+   * then return 1. Otherwise, 0 is returned.
+   * @see <a href="http://semver.org/">Semantic Versioning 2.0.0-rc.1</a>
+   */
+  private static int componentCompare(
+      final String oneComp, final String twoComp) {
+    if((oneComp == null) && (twoComp == null)) {
+      return 0;
+    }
+
+    if((oneComp == null) && (twoComp != null)) {
+      return -1;
+    }
+    
+    if((oneComp != null) && (twoComp == null)) { 
+      return 1;
+    }
+
+    boolean isOneInt = false;
+    boolean isTwoInt = false;
+    int oneInt = 0;
+    int twoInt = 0;
+
+    try {
+      oneInt = Integer.parseInt(oneComp);
+      isOneInt = true;
+    } catch(final NumberFormatException ex) {
+      isOneInt = false;
+    }
+
+    try {
+      twoInt = Integer.parseInt(twoComp);
+      isTwoInt = true;
+    } catch(final NumberFormatException ex) {
+      isTwoInt = false;
+    }
+
+    final int comp = ((isOneInt == true) && (isTwoInt == true)) ?
+        oneInt - twoInt :
+        oneComp.compareTo(twoComp);
+    final int compValue = (comp > 0) ? 1 : (comp < 0) ? -1 : 0;
+    
+    return compValue;
+  }
+}
diff --git a/src/main/java/com/capitati/omtc/core/negotiation/SemanticVersionComponent.java b/src/main/java/com/capitati/omtc/core/negotiation/SemanticVersionComponent.java
new file mode 100644
index 0000000..306a5dd
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/negotiation/SemanticVersionComponent.java
@@ -0,0 +1,27 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.negotiation;
+
+public enum SemanticVersionComponent {
+  INVALID,
+  PRE_RELEASE_AND_BUILD_VERSION,
+  PATCH_VERSION,
+  MINOR_VERSION,
+  MAJOR_VERSION
+}
diff --git a/src/main/java/com/capitati/omtc/core/negotiation/SemanticVersionParseException.java b/src/main/java/com/capitati/omtc/core/negotiation/SemanticVersionParseException.java
new file mode 100644
index 0000000..c11a013
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/negotiation/SemanticVersionParseException.java
@@ -0,0 +1,53 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.negotiation;
+
+public class SemanticVersionParseException extends Exception {
+  private static final long serialVersionUID = -3118190471319312408L;
+
+  private final String invalidVersion;
+  
+  public SemanticVersionParseException(final String theInvalidVersion) {
+    super();
+    invalidVersion = theInvalidVersion;
+  }
+
+  public SemanticVersionParseException(
+      final String theInvalidVersion, final Throwable theThrowable) {
+    super(theThrowable);
+    invalidVersion = theInvalidVersion;
+  }
+
+  public SemanticVersionParseException(
+      final String theInvalidVersion,
+      final Throwable theThrowable,
+      final boolean isSuppressionEnabled,
+      final boolean isWritableStackTrace) {
+    super(null, theThrowable, isSuppressionEnabled, isWritableStackTrace);
+    invalidVersion = theInvalidVersion;
+  }
+
+  public String getInvalidVersion() {
+    return invalidVersion;
+  }
+
+  public String getMessage() {
+    return String.format("Invalid semantic version: [%s]", invalidVersion);
+  }
+}
diff --git a/src/main/java/com/capitati/omtc/core/notification/IResourceDownloadObserver.java b/src/main/java/com/capitati/omtc/core/notification/IResourceDownloadObserver.java
new file mode 100644
index 0000000..ca6db59
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/notification/IResourceDownloadObserver.java
@@ -0,0 +1,24 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.notification;
+
+public interface IResourceDownloadObserver
+extends IResourceTaskObserver {
+
+}
diff --git a/src/main/java/com/capitati/omtc/core/notification/IResourceTaskObserver.java b/src/main/java/com/capitati/omtc/core/notification/IResourceTaskObserver.java
new file mode 100644
index 0000000..2dccf7e
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/notification/IResourceTaskObserver.java
@@ -0,0 +1,55 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.notification;
+
+import com.capitati.omtc.core.resources.IResource;
+import com.capitati.omtc.core.session.ISession;
+
+/**
+ * A generic resource task observer. On successful completion of a task the
+ * onSuccess() method shall be called. Whereas, on an error the onError()
+ * method shall be called. The onError() method provides an object, of type F,
+ * shall be provided which is the object that was used to invoke the task.
+ *
+ * @author ianjohnson
+ */
+public interface IResourceTaskObserver {
+  /**
+   * Called on successful completion of a resource task.
+   * 
+   * @param notification
+   * @param resource
+   * @param invokingSession
+   */
+  void onSuccess(
+      ISession invokingSession,
+      IResource resource);
+
+  /**
+   * Called when a resource task has failed.
+   * 
+   * @param notification
+   * @param invokingSession
+   * @param exception
+   */
+  void onError(
+      ISession session,
+      IResource resource,
+      Exception exception);
+}
diff --git a/src/main/java/com/capitati/omtc/core/notification/IResourceUploadObserver.java b/src/main/java/com/capitati/omtc/core/notification/IResourceUploadObserver.java
new file mode 100644
index 0000000..b406a7f
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/notification/IResourceUploadObserver.java
@@ -0,0 +1,23 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.notification;
+
+public interface IResourceUploadObserver extends IResourceTaskObserver {
+
+}
diff --git a/src/main/java/com/capitati/omtc/core/resources/IDerivedResource.java b/src/main/java/com/capitati/omtc/core/resources/IDerivedResource.java
new file mode 100644
index 0000000..51ce2fa
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/resources/IDerivedResource.java
@@ -0,0 +1,25 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.resources;
+
+import java.util.Date;
+
+public interface IDerivedResource extends IResource {
+  Date getLastChanged();
+}
diff --git a/src/main/java/com/capitati/omtc/core/resources/IPrimaryResource.java b/src/main/java/com/capitati/omtc/core/resources/IPrimaryResource.java
new file mode 100644
index 0000000..e62941b
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/resources/IPrimaryResource.java
@@ -0,0 +1,23 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.resources;
+
+public interface IPrimaryResource extends IResource {
+
+}
diff --git a/src/main/java/com/capitati/omtc/core/resources/IResource.java b/src/main/java/com/capitati/omtc/core/resources/IResource.java
new file mode 100644
index 0000000..72787df
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/resources/IResource.java
@@ -0,0 +1,29 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.resources;
+
+import java.net.URI;
+import java.util.Date;
+import java.util.UUID;
+
+public interface IResource {
+	UUID getIdentifier();
+	URI getURI();
+	Date getBirthDate();
+}
diff --git a/src/main/java/com/capitati/omtc/core/resources/IResourceReader.java b/src/main/java/com/capitati/omtc/core/resources/IResourceReader.java
new file mode 100644
index 0000000..c74539f
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/resources/IResourceReader.java
@@ -0,0 +1,26 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.resources;
+
+import java.io.IOException;
+
+public interface IResourceReader {
+  int read(byte[] buffer) throws IOException;
+  void close() throws IOException;
+}
diff --git a/src/main/java/com/capitati/omtc/core/resources/IResourceWriter.java b/src/main/java/com/capitati/omtc/core/resources/IResourceWriter.java
new file mode 100644
index 0000000..f605e26
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/resources/IResourceWriter.java
@@ -0,0 +1,26 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.resources;
+
+import java.io.IOException;
+
+public interface IResourceWriter {
+  void write(byte[] chunk, int chunkLength) throws IOException;
+  void close() throws IOException;
+}
diff --git a/src/main/java/com/capitati/omtc/core/scheduling/CompositionTicket.java b/src/main/java/com/capitati/omtc/core/scheduling/CompositionTicket.java
new file mode 100644
index 0000000..b9d1535
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/scheduling/CompositionTicket.java
@@ -0,0 +1,49 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.scheduling;
+
+import java.util.Date;
+import java.util.UUID;
+
+import com.capitati.omtc.core.engine.IEngine;
+import com.capitati.omtc.core.session.ISession;
+
+public class CompositionTicket<V> extends EngineTicket<V> {
+  private final IEngine composingEngine;
+  
+  public CompositionTicket(
+      final UUID theIdentifier,
+      final Date theStartDate,
+      final ISession theSession,
+      final V thePriority,
+      final IEngine theParticipatingEngine,
+      final IEngine theComposingEngine) {
+    super(
+        theIdentifier,
+        theStartDate,
+        theSession,
+        thePriority,
+        theParticipatingEngine);
+    composingEngine = theComposingEngine;
+  }
+
+  public IEngine getComposingEngine() {
+    return composingEngine;
+  }
+}
diff --git a/src/main/java/com/capitati/omtc/core/scheduling/EngineTicket.java b/src/main/java/com/capitati/omtc/core/scheduling/EngineTicket.java
new file mode 100644
index 0000000..d81bda6
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/scheduling/EngineTicket.java
@@ -0,0 +1,43 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.scheduling;
+
+import java.util.Date;
+import java.util.UUID;
+
+import com.capitati.omtc.core.engine.IEngine;
+import com.capitati.omtc.core.session.ISession;
+
+public class EngineTicket<V> extends Ticket<V> {
+  private final IEngine participatingEngine;
+
+  public EngineTicket(
+      final UUID theIdentifier,
+      final Date theStartDate,
+      final ISession theSession,
+      final V thePriority,
+      final IEngine theParticipatingEngine) {
+    super(theIdentifier, theStartDate, theSession, thePriority);
+    participatingEngine = theParticipatingEngine;
+  }
+
+  public IEngine getParticipatingEngine() {
+    return participatingEngine;
+  }
+}
diff --git a/src/main/java/com/capitati/omtc/core/scheduling/EvaluationTicket.java b/src/main/java/com/capitati/omtc/core/scheduling/EvaluationTicket.java
new file mode 100644
index 0000000..63f5423
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/scheduling/EvaluationTicket.java
@@ -0,0 +1,41 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.scheduling;
+
+import java.util.Date;
+import java.util.UUID;
+
+import com.capitati.omtc.core.engine.IEngine;
+import com.capitati.omtc.core.session.ISession;
+
+public class EvaluationTicket<V> extends EngineTicket<V> {
+  public EvaluationTicket(
+      final UUID theIdentifier,
+      final Date theStartDate,
+      final ISession theSession,
+      final V thePriority,
+      final IEngine theParticipatingEngine) {
+    super(
+        theIdentifier,
+        theStartDate,
+        theSession,
+        thePriority,
+        theParticipatingEngine);
+  }
+}
diff --git a/src/main/java/com/capitati/omtc/core/scheduling/IPriority.java b/src/main/java/com/capitati/omtc/core/scheduling/IPriority.java
new file mode 100644
index 0000000..021cc5c
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/scheduling/IPriority.java
@@ -0,0 +1,36 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.scheduling;
+
+/**
+ * This presents a priority that will be used to schedule a task in the MT API.
+ * 
+ * @author ianjohnson
+ *
+ * @param <V> the type of the priority value.
+ */
+public interface IPriority<V> {
+  /**
+   * A getter function to provide the caller with a task's priority. This allows
+   * late binding of any priority parameters at call time.
+   * 
+   * @return The priority's value of type V.
+   */
+  V getPriority();
+}
diff --git a/src/main/java/com/capitati/omtc/core/scheduling/IPriorityMechanism.java b/src/main/java/com/capitati/omtc/core/scheduling/IPriorityMechanism.java
new file mode 100644
index 0000000..d38d1b8
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/scheduling/IPriorityMechanism.java
@@ -0,0 +1,43 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.scheduling;
+
+/**
+ * Implementers should define the priority policy for their product. A priority
+ * description is used to provide the parameters that shall be used to generate
+ * a priority object. The description may include SLA, due date, user's price
+ * plan, one-off task payment details that would improve a task's priority etc.
+ *
+ * @author ianjohnson
+ *
+ * @param <V> the type of the priority value.
+ * @param <D> the type of the priority description. This is a type that provides
+ * all the parameters that will be combined to create a priority object.
+ */
+public interface IPriorityMechanism<V, D> {
+  /**
+   * Taking a priority description generate a priority object that is the
+   * combination of the description.
+   * 
+   * @param priorityDescription - the parameters to use to generate the priority.
+   * @return A priority object.
+   * @throws Exception
+   */
+  IPriority<V> getPriority(D priorityDescription) throws Exception;
+}
diff --git a/src/main/java/com/capitati/omtc/core/scheduling/ITicketObserver.java b/src/main/java/com/capitati/omtc/core/scheduling/ITicketObserver.java
new file mode 100644
index 0000000..7d778a1
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/scheduling/ITicketObserver.java
@@ -0,0 +1,58 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.scheduling;
+
+/**
+ * An observer that watches for tickets starting and completing.
+ *
+ * @author ian
+ *
+ * @param <T> - the type of the ticket that has completed.
+ */
+public interface ITicketObserver<T extends Ticket<V>, V> {
+  /**
+   * Notify the observer that a ticketed task has been submitted. This method
+   * shall be called at post-submission and pre-starting time.
+   *
+   * @param ticket - the ticket representing the submitted task.
+   */
+  void notifySubmitted(T ticket);
+
+  /**
+   * Notify the observer that the ticketed task as begun.
+   * 
+   * @param ticket - the ticket that has started.
+   */
+  void notifyStarted(T ticket);
+
+  /**
+   * Notify the observer that the ticketed task has ended successfully.
+   * 
+   * @param ticket - the ticket that has completed.
+   */
+  void notifySuccess(T ticket);
+
+  /**
+   * Notify the observer that the ticketed task has generated an error.
+   *
+   * @param ticket - the ticket that has completed.
+   * @param exception - the exception that represents the error.
+   */
+  void notifyError(T ticket, Exception exception);
+}
diff --git a/src/main/java/com/capitati/omtc/core/scheduling/QueryTicket.java b/src/main/java/com/capitati/omtc/core/scheduling/QueryTicket.java
new file mode 100644
index 0000000..3147f49
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/scheduling/QueryTicket.java
@@ -0,0 +1,41 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.scheduling;
+
+import java.util.Date;
+import java.util.UUID;
+
+import com.capitati.omtc.core.engine.IEngine;
+import com.capitati.omtc.core.session.ISession;
+
+public class QueryTicket<V> extends EngineTicket<V> {
+  public QueryTicket(
+      final UUID theIdentifier,
+      final Date theStartDate,
+      final ISession theSession,
+      final V thePriority,
+      final IEngine theParticipatingEngine) {
+    super(
+        theIdentifier,
+        theStartDate,
+        theSession,
+        thePriority,
+        theParticipatingEngine);
+  }
+}
diff --git a/src/main/java/com/capitati/omtc/core/scheduling/TestingTicket.java b/src/main/java/com/capitati/omtc/core/scheduling/TestingTicket.java
new file mode 100644
index 0000000..0c6735d
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/scheduling/TestingTicket.java
@@ -0,0 +1,41 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.scheduling;
+
+import java.util.Date;
+import java.util.UUID;
+
+import com.capitati.omtc.core.engine.IEngine;
+import com.capitati.omtc.core.session.ISession;
+
+public class TestingTicket<V> extends EngineTicket<V> {
+  public TestingTicket(
+      final UUID theIdentifier,
+      final Date theStartDate,
+      final ISession theSession,
+      final V thePriority,
+      final IEngine theParticipatingEngine) {
+    super(
+        theIdentifier,
+        theStartDate,
+        theSession,
+        thePriority,
+        theParticipatingEngine);
+  }
+}
diff --git a/src/main/java/com/capitati/omtc/core/scheduling/Ticket.java b/src/main/java/com/capitati/omtc/core/scheduling/Ticket.java
new file mode 100644
index 0000000..0bd7114
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/scheduling/Ticket.java
@@ -0,0 +1,66 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.scheduling;
+
+import java.util.Date;
+import java.util.UUID;
+
+import com.capitati.omtc.core.session.ISession;
+
+public abstract class Ticket<V> {
+  private final UUID identifier;
+  private final Date startDate;
+  private final ISession session;
+  private final V priority;
+
+  protected Date endDate;
+
+  protected Ticket(
+      final UUID theIdentifier,
+      final Date theStartDate,
+      final ISession theSession,
+      final V thePriority) {
+    super();
+    identifier = theIdentifier;
+    startDate = theStartDate;
+    session = theSession;
+    priority = thePriority;
+    endDate = null;
+  }
+
+  public UUID getIdentifier() {
+    return identifier;
+  }
+
+  public Date getStartDate() {
+    return startDate;
+  }
+
+  public Date getEndDate() {
+    return endDate;
+  }
+
+  public ISession getSession() {
+    return session;
+  }
+
+  public V getPriority() {
+    return priority;
+  }
+}
diff --git a/src/main/java/com/capitati/omtc/core/scheduling/TrainingTicket.java b/src/main/java/com/capitati/omtc/core/scheduling/TrainingTicket.java
new file mode 100644
index 0000000..741311f
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/scheduling/TrainingTicket.java
@@ -0,0 +1,41 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.scheduling;
+
+import java.util.Date;
+import java.util.UUID;
+
+import com.capitati.omtc.core.engine.IEngine;
+import com.capitati.omtc.core.session.ISession;
+
+public class TrainingTicket<V> extends EngineTicket<V> {
+  public TrainingTicket(
+      final UUID theIdentifier,
+      final Date theStartDate,
+      final ISession theSession,
+      final V thePriority,
+      final IEngine theParticipatingEngine) {
+    super(
+        theIdentifier,
+        theStartDate,
+        theSession,
+        thePriority,
+        theParticipatingEngine);
+  }
+}
diff --git a/src/main/java/com/capitati/omtc/core/scheduling/TranslationTicket.java b/src/main/java/com/capitati/omtc/core/scheduling/TranslationTicket.java
new file mode 100644
index 0000000..aa1a5c7
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/scheduling/TranslationTicket.java
@@ -0,0 +1,43 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.scheduling;
+
+import java.util.Date;
+import java.util.UUID;
+
+import com.capitati.omtc.core.session.ISession;
+import com.capitati.omtc.core.translation.Translator;
+
+public class TranslationTicket<V> extends Ticket<V> {
+  private final Translator<V> translator;
+
+  public TranslationTicket(
+      final UUID theIdentifier,
+      final Date theStartDate,
+      final ISession theSession,
+      final V thePriority,
+      final Translator<V> theTranslator) {
+    super(theIdentifier, theStartDate, theSession, thePriority);
+    translator = theTranslator;
+  }
+
+  public Translator<V> getTranslator() {
+    return translator;
+  }
+}
diff --git a/src/main/java/com/capitati/omtc/core/scheduling/UpdateTicket.java b/src/main/java/com/capitati/omtc/core/scheduling/UpdateTicket.java
new file mode 100644
index 0000000..10955c4
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/scheduling/UpdateTicket.java
@@ -0,0 +1,41 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.scheduling;
+
+import java.util.Date;
+import java.util.UUID;
+
+import com.capitati.omtc.core.engine.IEngine;
+import com.capitati.omtc.core.session.ISession;
+
+public class UpdateTicket<V> extends EngineTicket<V> {
+  public UpdateTicket(
+      final UUID theIdentifier,
+      final Date theStartDate,
+      final ISession theSession,
+      final V thePriority,
+      final IEngine theParticipatingEngine) {
+    super(
+        theIdentifier,
+        theStartDate,
+        theSession,
+        thePriority,
+        theParticipatingEngine);
+  }
+}
diff --git a/src/main/java/com/capitati/omtc/core/security/IUser.java b/src/main/java/com/capitati/omtc/core/security/IUser.java
new file mode 100644
index 0000000..092cddd
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/security/IUser.java
@@ -0,0 +1,42 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.security;
+
+import java.util.UUID;
+
+/**
+ * A machine translation service user.
+ * 
+ * @author ian
+ */
+public interface IUser {
+  /**
+   * The unique identifier for the user.
+   * 
+   * @return The user's unique identity.
+   */
+  UUID getIdentifier();
+
+  /**
+   * Retrieve the user's roles.
+   * 
+   * @return The roles of the user.
+   */
+  Role[] getRoles();
+}
diff --git a/src/main/java/com/capitati/omtc/core/security/Role.java b/src/main/java/com/capitati/omtc/core/security/Role.java
new file mode 100644
index 0000000..bf1e3c4
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/security/Role.java
@@ -0,0 +1,43 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.security;
+
+public enum Role {
+  INVALID(-1, "Invalid"),
+  TRANSLATOR(1, "Translator"),
+  ENGINE_MANAGER(3, "Engine Manager"),
+  ADMINISTRATOR(7, "Administrator"),
+  SERVICE_ADMINISTRATOR(8, "Service Administrator");
+
+  private final int code;
+  private final String name; 
+
+  private Role(final int theCode, final String theName) {
+    code = theCode;
+    name = theName;
+  }
+
+  public int getCode() {
+    return code;
+  }
+
+  public String getName() {
+    return name;
+  }
+}
diff --git a/src/main/java/com/capitati/omtc/core/security/User.java b/src/main/java/com/capitati/omtc/core/security/User.java
new file mode 100644
index 0000000..bca6e0e
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/security/User.java
@@ -0,0 +1,39 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.security;
+
+import java.util.UUID;
+
+public abstract class User implements IUser {
+  private final UUID userId;
+  private final Role role;
+  
+  protected User(final UUID theUserId, final Role theRole) {
+    userId = theUserId;
+    role = theRole;
+  }
+
+  public UUID getIdentifier() {
+    return userId;
+  }
+
+  public Role getRole() {
+    return role;
+  }
+}
diff --git a/src/main/java/com/capitati/omtc/core/session/IEngineAssignableSession.java b/src/main/java/com/capitati/omtc/core/session/IEngineAssignableSession.java
new file mode 100644
index 0000000..d838e72
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/session/IEngineAssignableSession.java
@@ -0,0 +1,60 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.session;
+
+import com.capitati.omtc.core.engine.IEngine;
+import com.capitati.omtc.core.security.IUser;
+
+/**
+ * A mixin to provide methods to grant and revoke users access to constructed
+ * engines in the machine translation service. Implementers of this interface
+ * should associate an engine. And optionally storing the record of a grant or
+ * revocation into some persistent backing store. Whether the backing store is
+ * a database or authorisation service is implementation defined.
+ *
+ * @author ianjohnson
+ */
+public interface IEngineAssignableSession
+extends IEngineRetrievableSession, IUserRetrievableSession {
+  /**
+   * Associate a user with an engine. This association should allow the user
+   * to use the engine for a {@link com.capitati.omtc.core.translation.Translator}
+   * object. Optionally, the implementation should back this association to some
+   * persistent backing store.
+   * 
+   * @param engine - the engine to grant.
+   * @param theUser - the grantee.
+   * @throws Exception Any error that is encountered.
+   */
+  void grantEngineToUser(IEngine engine, IUser theUser) throws Exception;
+
+  /**
+   * Dissociate a user from an engine. The user shall no longer be able to use
+   * an engine to build a {@link com.capitati.omtc.core.translation.Translator}
+   * object. Whether the existing translator objects, that use the engine,
+   * shall be destroyed immediately, or that the engine is no longer available
+   * for use in a translator is to implementation defined. Optionally, the
+   * implementation should back the dissociation to a persistent backing store.
+   * 
+   * @param engine - the engine to revoke.
+   * @param theUser - the revokee.
+   * @throws Exception Any error that is encountered.
+   */
+  void revokeEngineFromUser(IEngine engine, IUser theUser) throws Exception;
+}
diff --git a/src/main/java/com/capitati/omtc/core/session/IEngineRetrievableSession.java b/src/main/java/com/capitati/omtc/core/session/IEngineRetrievableSession.java
new file mode 100644
index 0000000..d2ee5bb
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/session/IEngineRetrievableSession.java
@@ -0,0 +1,10 @@
+package com.capitati.omtc.core.session;
+
+import java.util.Set;
+
+import com.capitati.omtc.core.engine.IEngine;
+import com.google.common.base.Predicate;
+
+public interface IEngineRetrievableSession {
+  Set<IEngine> retrieveEngines(Predicate<IEngine> filter) throws Exception;
+}
diff --git a/src/main/java/com/capitati/omtc/core/session/IResourceTransferDelegate.java b/src/main/java/com/capitati/omtc/core/session/IResourceTransferDelegate.java
new file mode 100644
index 0000000..489bdde
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/session/IResourceTransferDelegate.java
@@ -0,0 +1,71 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.session;
+
+import com.capitati.omtc.core.resources.IResource;
+import com.capitati.omtc.core.resources.IResourceReader;
+import com.capitati.omtc.core.resources.IResourceWriter;
+
+/**
+ * The delegated resource transfer mechanism.
+ * 
+ * @author ianjohnson
+ */
+public interface IResourceTransferDelegate {
+  /**
+   * Constructs an instance of {@link com.capitati.omtc.core.resources.IResourceReader}
+   * which is an object that is used to read chunks of data from a source
+   * resource. Implementers of this method should take this opportunity to
+   * open a resource where ever that may be, e.g., local disk, remote client.
+   *
+   * @param theInvokingSession - the session for whom this method is being called.
+   * @return An implementation of the {@link com.capitati.omtc.core.resources.IResourceReader}
+   * interface that shall provide data for a resource.
+   * @throws Exception On any error encountered.
+   */
+  IResourceReader getResourceReader(ISession theInvokingSession) throws Exception;
+
+  /**
+   * Constructs an instance of {@link com.capitati.omtc.core.resources.IResourceWriter}
+   * which is an object that is used to write chunks of data to a destination
+   * resource. Implementers of this method should take this opportunity to
+   * open a resource where ever it may needed to be, e.g., local disk, remote client.
+   * 
+   * @param theInvokingSession - the session for whom this method is being called.
+   * @return An implementation of the {@link com.capitati.omtc.core.resources.IResourceWriter}
+   * interface that is to handle the writing of resource data.
+   * @throws Exception On any error encountered.
+   */
+  IResourceWriter getResourceWriter(ISession theInvokingSession) throws Exception;
+
+  /**
+   * Implementers of this method should return a {@link com.capitati.omtc.core.resources.IResource}
+   * object that represents the resource that is begin transfered.
+   * Please note: for documents, translation memories, and glossaries etc instances of
+   * {@link com.capitati.omtc.core.resources.IPrimaryResource} should be
+   * constructed. However, for resources that are derived, e.g., engines, then
+   * instances of type {@link com.capitati.omtc.core.resources.IDerivedResource}
+   * should be returned.
+   *
+   * @param theInvokingSession - the session that invoked the transfer action.
+   * @return A {@link com.capitati.omtc.core.resources.IResource}
+   * object that presents the resource uploaded
+   */
+  IResource getResource(ISession theInvokingSession);
+}
diff --git a/src/main/java/com/capitati/omtc/core/session/IRoleAssignableSession.java b/src/main/java/com/capitati/omtc/core/session/IRoleAssignableSession.java
new file mode 100644
index 0000000..8948634
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/session/IRoleAssignableSession.java
@@ -0,0 +1,50 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.session;
+
+import com.capitati.omtc.core.security.IUser;
+import com.capitati.omtc.core.security.Role;
+
+/**
+ * A mixin for providing a session the ability to grant and revoke roles from
+ * users of the machine translation service. Implementers of this interface
+ * should integrate with any back-end authorisation service that may be used
+ * alongside the concrete service.
+ * 
+ * @author ianjohnson
+ */
+public interface IRoleAssignableSession extends IUserRetrievableSession {
+  /**
+   * Grant a role to a user.
+   * 
+   * @param theRole - the role to grant.
+   * @param theUser - the user.
+   * @throws Exception On any errors that occur during the granting process.
+   */
+  void grantRoleToUser(Role theRole, IUser theUser) throws Exception;
+
+  /**
+   * Revoke a role from a user.
+   * 
+   * @param theRole - the role to revoke from the user.
+   * @param theUser - the user.
+   * @throws Exception On any errors that occur during the revocation process.
+   */
+  void revokeRoleFromUser(Role theRole, IUser theUser) throws Exception;
+}
diff --git a/src/main/java/com/capitati/omtc/core/session/ISession.java b/src/main/java/com/capitati/omtc/core/session/ISession.java
new file mode 100644
index 0000000..d6245ed
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/session/ISession.java
@@ -0,0 +1,120 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.session;
+
+import java.util.Set;
+import java.util.UUID;
+import java.util.concurrent.Future;
+
+import javax.naming.OperationNotSupportedException;
+
+import com.capitati.omtc.core.notification.IResourceDownloadObserver;
+import com.capitati.omtc.core.notification.IResourceUploadObserver;
+import com.capitati.omtc.core.resources.IResource;
+import com.google.common.base.Predicate;
+
+/**
+ * A machine translation service session. This session is <em>user-less</em>;
+ * this session is for services where user identity is not crucial for using the
+ * service.
+ * 
+ * @author ian
+ */
+public interface ISession {
+  /**
+   * Get the session's unique identifier.
+   * 
+   * @return The unique identifier that is of type {@link java.util.UUID}.
+   */
+  UUID getIdentifier();
+
+  /**
+   * Upload a resource to the service. The upload delegate shall be called to
+   * implement the actual mechanism that shall transfer resource data. If
+   * specified the {@link com.capitati.omtc.core.notification.IResourceUploadObserver}
+   * object shall be notified when the uploading of the resource has completed:
+   * either on success or failure.
+   * 
+   * <p>The returning {@link java.util.concurrent.Future} object,
+   * and the optional observer, allows callers to wait synchronously or
+   * asynchronously for upload completion.
+   * 
+   * @param theResourceUploaderDelegate - the delegated uploader mechanism.
+   * @param theResourceUploadObserver - optional observer that is notified
+   * once the uploading task has completed, either successfully or unsuccessfully.
+   * @return A {@link java.util.concurrent.Future} object that waits on the
+   * availability of the {@link com.capitati.omtc.core.resources.IResource} object
+   * that represents the resource once uploaded.
+   * @throws OperationNotSupportedException If no executor service was specified.
+   * @throws IllegalArgumentException If no uploading delegate has been
+   * provided.
+   */
+  Future<IResource> uploadResource(
+      IResourceTransferDelegate theResourceUploaderDelegate,
+      IResourceUploadObserver theResourceUploadObserver)
+  throws OperationNotSupportedException;
+
+  /**
+   * Download a resource from the service. The download delegate shall be called to
+   * implement the actual mechanism that shall transfer resource data. If
+   * specified the {@link com.capitati.omtc.core.notification.IResourceDownloadObserver}
+   * object shall be notified when the downloading of the resource has completed:
+   * either on success or failure.
+   * 
+   * <p>The returning {@link java.util.concurrent.Future} object,
+   * and the optional observer, allows callers to wait synchronously or
+   * asynchronously for the downloading to complete.
+   * 
+   * @param theResourceDownloaderDelegate - the delegated downloading mechanism.
+   * @param theResourceDownloadObserver - optional observer that is notified
+   * once the downloading task has completed, either successfully or unsuccessfully.
+   * @return A {@link java.util.concurrent.Future} object that waits on the
+   * availability of the {@link com.capitati.omtc.core.resources.IResource} object
+   * that represents the resource once downloaded.
+   * @throws OperationNotSupportedException If no executor service was specified.
+   * @throws IllegalArgumentException If no uploading delegate had been
+   * provided.
+   */
+  Future<IResource> downloadResource(
+      IResourceTransferDelegate theResourceDownloaderDelegate,
+      IResourceDownloadObserver theResourceDownloadObserver)
+  throws OperationNotSupportedException;
+
+  /**
+   * Remove a resource. If the resource implements
+   * {@link com.capitati.omtc.core.commons.IDisposable} the the method
+   * {@link com.capitati.omtc.core.commons.IDisposable#dispose} should be
+   * called to dispose of any used system resources, e.g., disk space.
+   *
+   * @param resource - the resource to remove.
+   * @throws Exception On an error.
+   */
+  void removeResource(IResource resource) throws Exception;
+
+  /**
+   * This method shall return a set of resources that belong to the session.
+   * 
+   * @param theFilter - the predicate that shall filter the resources returned.
+   * @return A {@link java.util.Set} of {@link com.capitati.omtc.core.resource.IResource}
+   * objects that are owned by the session and meet the predicate.
+   * @throws Exception on error evaluating the predicate.
+   */
+  Set<IResource> retrieveResources(Predicate<IResource> theFilter)
+  throws Exception;
+}
\ No newline at end of file
diff --git a/src/main/java/com/capitati/omtc/core/session/IUserRetrievableSession.java b/src/main/java/com/capitati/omtc/core/session/IUserRetrievableSession.java
new file mode 100644
index 0000000..6c4eb05
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/session/IUserRetrievableSession.java
@@ -0,0 +1,28 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.session;
+
+import java.util.Set;
+
+import com.capitati.omtc.core.security.IUser;
+import com.google.common.base.Predicate;
+
+public interface IUserRetrievableSession {
+  Set<IUser> retrieveUsers(Predicate<IUser> filter) throws Exception;
+}
diff --git a/src/main/java/com/capitati/omtc/core/session/IUserSession.java b/src/main/java/com/capitati/omtc/core/session/IUserSession.java
new file mode 100644
index 0000000..02754af
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/session/IUserSession.java
@@ -0,0 +1,36 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.session;
+
+import com.capitati.omtc.core.security.IUser;
+
+/**
+ * A session that is associated with a user. This session would be used by a
+ * service implementation that requires user identity.
+ * 
+ * @author ian
+ */
+public interface IUserSession extends ISession {
+  /**
+   * Retrieve the associated user object for the session.
+   * 
+   * @return The session's associated user object.
+   */
+  IUser getUser();
+}
diff --git a/src/main/java/com/capitati/omtc/core/session/Session.java b/src/main/java/com/capitati/omtc/core/session/Session.java
new file mode 100644
index 0000000..6731325
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/session/Session.java
@@ -0,0 +1,232 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.session;
+
+import java.util.UUID;
+import java.util.concurrent.Callable;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Future;
+
+import javax.naming.OperationNotSupportedException;
+
+import com.capitati.omtc.core.notification.IResourceDownloadObserver;
+import com.capitati.omtc.core.notification.IResourceUploadObserver;
+import com.capitati.omtc.core.resources.IResource;
+import com.capitati.omtc.core.resources.IResourceReader;
+import com.capitati.omtc.core.resources.IResourceWriter;
+
+/**
+ * A machine translation service session. This session is <em>user-less</em>;
+ * this session is for services where user identity is not crucial for using the
+ * service.
+ * 
+ * @author ianjohnson
+ */
+public abstract class Session implements ISession {
+  private static final int DEFAULT_BUFFER_SIZE = 1024 * 1024; // 1Mb
+
+  private final UUID id;
+  private final int bufferSize;
+  protected final ExecutorService executor;
+
+  /**
+   * Construct a session that does not support uploading or downloading of
+   * resources.
+   * 
+   * @param theIdentifier - the unique identifier for the session.
+   */
+  protected Session(final UUID theIdentifier) {
+    super();
+    id = theIdentifier;
+    bufferSize = DEFAULT_BUFFER_SIZE;
+    executor = null;
+  }
+
+  /**
+   * Construct a session that supports uploading and downloading of resources.
+   * 
+   * @param theIdentifier - the unique identifier for the session.
+   * @param theDelegateExecutorService - the executor service in which the
+   * upload and download delegates shall run.
+   */
+  protected Session(
+      final UUID theIdentifier,      
+      final ExecutorService theDelegationExecutorService) {
+    super();
+    id = theIdentifier;
+    executor = theDelegationExecutorService;
+    bufferSize = (executor != null) ? DEFAULT_BUFFER_SIZE : -1;
+  }
+
+  /**
+   * Construct a session that supports uploading and downloading of resources.
+   * 
+   * @param theIdentifier - the unique identifier for the session.
+   * @param theDelegateExecutorService - the executor service in which the
+   * upload and download delegates shall run.
+   * @param theTransferBufferSize - the number of bytes available to the
+   * upload and download transfer buffer.
+   */
+  protected Session(
+      final UUID theIdentifier,      
+      final ExecutorService theDelegationExecutorService,
+      final int theTransferBufferSize) {
+    super();
+    id = theIdentifier;
+    bufferSize = (theTransferBufferSize > 0) ? theTransferBufferSize : DEFAULT_BUFFER_SIZE;
+    executor = theDelegationExecutorService;
+  }
+
+  public UUID getIdentifier() {
+    return id;
+  }
+
+  public Future<IResource> uploadResource(
+      final IResourceTransferDelegate theResourceUploaderDelegate,
+      final IResourceUploadObserver theResourceUploadObserver)
+  throws OperationNotSupportedException {
+    if(executor == null) {
+      throw new OperationNotSupportedException("");
+    }
+
+    if(theResourceUploaderDelegate == null) {
+      throw new IllegalArgumentException("No uploader delegate specified.");
+    }
+
+    final ISession invokingSession = this;
+    final Callable<IResource> uploadTask = new Callable<IResource>() {
+      public IResource call() throws Exception {
+        final IResource resource =
+            theResourceUploaderDelegate.getResource(invokingSession);
+
+        try {
+          upload();
+
+          if(theResourceUploadObserver != null) {
+            theResourceUploadObserver.onSuccess(invokingSession, resource);
+          }
+        } catch(final Exception ex) {
+          if(theResourceUploadObserver != null) {
+            theResourceUploadObserver.onError(invokingSession, resource, ex);
+          }
+          throw ex;
+        }
+        
+        return resource;
+      }
+      
+      private void upload() throws Exception {
+        final IResourceReader resourceReader =
+            theResourceUploaderDelegate.getResourceReader(invokingSession);
+
+        try {
+          final IResourceWriter resourceWriter =
+              theResourceUploaderDelegate.getResourceWriter(invokingSession);
+      
+          try {
+            Session.copyBytes(resourceReader, resourceWriter, bufferSize);
+          } finally {
+            resourceWriter.close();
+          }
+        } finally {
+          resourceReader.close();
+        }
+      }
+    };
+    final Future<IResource> future = executor.submit(uploadTask);
+
+    return future;
+  }
+
+  public Future<IResource> downloadResource(
+      final IResourceTransferDelegate theResourceDownloaderDelegate,
+      final IResourceDownloadObserver theResourceDownloadObserver) {
+    if(theResourceDownloaderDelegate == null) {
+      throw new IllegalArgumentException("No downloader delegate specified.");
+    }
+
+    final ISession invokingSession = this;
+    final Callable<IResource> downloadTask = new Callable<IResource>() {
+      public IResource call() throws Exception {
+        final IResource resource =
+            theResourceDownloaderDelegate.getResource(invokingSession);
+
+        try {
+          download();
+
+          if(theResourceDownloadObserver != null) {
+            theResourceDownloadObserver.onSuccess(invokingSession, resource);
+          }
+        } catch(final Exception ex) {
+          if(theResourceDownloadObserver != null) {
+            theResourceDownloadObserver.onError(invokingSession, resource, ex);
+            throw ex;
+          }
+        }
+
+        return resource;
+      }
+      
+      private void download() throws Exception {
+        final IResourceWriter resourceWriter =
+            theResourceDownloaderDelegate.getResourceWriter(invokingSession);
+
+        try {
+          final IResourceReader resourceReader =
+              theResourceDownloaderDelegate.getResourceReader(invokingSession);
+
+          try {
+            Session.copyBytes(resourceReader, resourceWriter, bufferSize);
+          } finally {
+            resourceReader.close();
+          }
+        } finally {
+          resourceWriter.close();
+        }
+      }
+    };
+    final Future<IResource> future = executor.submit(downloadTask);
+    
+    return future;
+  }
+
+  /**
+   * Writes bytes, read from a resource reader, to a resource writer. This
+   * copies the bytes from a source resource to a destination resource,
+   * respectively.
+   * 
+   * @param resourceReader - the object that shall read the source resource data.
+   * @param resourceWriter - the object that shall write the resource data to
+   * the destination resource.
+   * @param bufferSize - the number of bytes used to build the buffer.
+   * @throws Exception on an error reading from, or writing to the resources.
+   */
+  private static void copyBytes(
+      final IResourceReader resourceReader,
+      final IResourceWriter resourceWriter,
+      final int bufferSize) throws Exception {
+    final byte[] readBuffer = new byte[bufferSize];
+    int bytesRead = resourceReader.read(readBuffer);
+
+    while(bytesRead > -1) {
+      resourceWriter.write(readBuffer, bytesRead);
+      bytesRead = resourceReader.read(readBuffer);
+    }
+  }
+}
diff --git a/src/main/java/com/capitati/omtc/core/session/UserSession.java b/src/main/java/com/capitati/omtc/core/session/UserSession.java
new file mode 100644
index 0000000..6fa549c
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/session/UserSession.java
@@ -0,0 +1,88 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.session;
+
+import java.util.UUID;
+import java.util.concurrent.ExecutorService;
+
+import com.capitati.omtc.core.security.IUser;
+
+/**
+ * A session that is associated with a user. This session would be used by a
+ * service implementation that requires user identity.
+ * 
+ * @author ianjohnson
+ */
+public abstract class UserSession extends Session implements IUserSession {
+  protected final IUser user;
+
+  /**
+   * Construct a user session that does not support downloading or uploading.
+   * 
+   * @param theIdentifier - the unique identifier for the session.
+   * @param theUser - the associated user object.
+   */
+  protected UserSession(final UUID theIdentifier, final IUser theUser) {
+    super(theIdentifier);
+    user = theUser;
+  }
+
+  /**
+   * Construct a user session that supports downloading and uploading.
+   * 
+   * @param theIdentifier - the unique identifier for the session.
+   * @param theUser - the associated user object.
+   * @param theDelegateExecutorService - the executor service in which the
+   * upload and download delegates shall run.
+   */
+  protected UserSession(
+      final UUID theIdentifier,
+      final IUser theUser,
+      final ExecutorService theDelegationExecutorService) {
+    super(theIdentifier, theDelegationExecutorService);
+    user = theUser;
+  }
+
+  /**
+   * 
+   * @param theIdentifier - the unique identifier for the session.
+   * @param theUser - the associated user object.
+   * @param theDelegationExecutorService -the executor service in which the
+   * upload and download delegates shall run.
+   * @param theTransferBufferSize - the number of bytes available to the
+   * upload and download transfer buffer.
+   */
+  protected UserSession(
+      final UUID theIdentifier,
+      final IUser theUser,
+      final ExecutorService theDelegationExecutorService,
+      final int theTransferBufferSize) {
+    super(theIdentifier, theDelegationExecutorService, theTransferBufferSize);
+    user = theUser;
+  }
+
+  /**
+   * Retrieve the associated user object for the session.
+   * 
+   * @return The session's associated user object.
+   */
+  public IUser getUser() {
+    return user;
+  }
+}
diff --git a/src/main/java/com/capitati/omtc/core/translation/Translator.java b/src/main/java/com/capitati/omtc/core/translation/Translator.java
new file mode 100644
index 0000000..3ef63a3
--- /dev/null
+++ b/src/main/java/com/capitati/omtc/core/translation/Translator.java
@@ -0,0 +1,120 @@
+/*
+ * Copyright Capita Translation and Interpreting 2013
+ *
+ * This file is part of OMTC.
+ *
+ * OMTC is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * OMTC is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with OMTC.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package com.capitati.omtc.core.translation;
+
+import java.util.HashSet;
+import java.util.Set;
+
+import com.capitati.omtc.core.engine.IEngine;
+import com.capitati.omtc.core.resources.IPrimaryResource;
+import com.capitati.omtc.core.scheduling.IPriority;
+import com.capitati.omtc.core.scheduling.ITicketObserver;
+import com.capitati.omtc.core.scheduling.TranslationTicket;
+import com.google.common.base.Predicate;
+
+/**
+ * An associative class that brings together an engine, glossaries and
+ * translation memories. These resources are to be used as a translator.
+ * 
+ * @author ian
+ *
+ * @param <P> - the type of the priority's value.
+ */
+public abstract class Translator<V> {
+  private final IEngine engine;
+  private final Set<IPrimaryResource> glossaries =
+      new HashSet<IPrimaryResource>();
+  private final Set<IPrimaryResource> translationMemories =
+      new HashSet<IPrimaryResource>();
+
+  protected Translator(final IEngine theEngine) {
+    super();
+    engine = theEngine;
+  }
+
+  protected Translator(
+      final IEngine theEngine,
+      final Set<IPrimaryResource> theGlossaries,
+      final Set<IPrimaryResource> theTranslationMemories) {
+    super();
+    engine = theEngine;
+    glossaries.addAll(theGlossaries);
+    translationMemories.addAll(theTranslationMemories);
+  }
+
+  public IEngine getEngine() {
+    return engine;
+  }
+
+  public Set<IPrimaryResource> getGlossaries() {
+    return glossaries;
+  }
+
+  public Set<IPrimaryResource> getTranslationMemories() {
+    return translationMemories;
+  }
+
+  /**
+   * Schedule a translation for a primary resource. It is implementation
+   * defined which kind of primary resources shall be translated.
+   *
+   * @param session - the invoking session.
+   * @param resourceToTranslate - the primary resource to translate.
+   * @param thePriority - the requested priority.
+   * @param translationObserver - the observer that listens for the translation
+   * task to starting and complete.
+   * @return A translation ticket.
+   * @throws Exception On an error.
+   */
+  public abstract TranslationTicket<V> scheduleTranslation(
+      IPrimaryResource resourceToTranslate,
+      IPriority<V> thePriority,
+      ITicketObserver<TranslationTicket<V>, V> translationObserver)
+  throws Exception;
+
+  /**
+   * Schedule a translation for a single sentence.
+   *
+   * @param session - the invoking session.
+   * @param sourceSentence - the sentence to translate.
+   * @param thePriority - the requested priority.
+   * @param translationObserver - the observer that listens for the translation
+   * task to starting and complete.
+   * @return A translation ticket.
+   * @throws Exception On an error.
+   */
+  public abstract TranslationTicket<V> scheduleTranslation(
+      String sourceSentence,
+      IPriority<V> thePriority,
+      ITicketObserver<TranslationTicket<V>, V> translationObserver)
+  throws Exception;
+
+  /**
+   * Retrieve the dispensed translation tickets.
+   * 
+   * @param filter - a predicate used to filter the translation tickets.
+   * @return A {@link java.util.Set} of currently scheduled translation
+   * tickets. It is the implementations responsibility to manage the in-flight
+   * collection of tickets.
+   *
+   * @throws Exception
+   */
+  public abstract Set<TranslationTicket<V>> retrieveTranslations(
+      Predicate<TranslationTicket<V>> filter) throws Exception;
+}
diff --git a/src/test/java/com/capitati/omtc/core/negotiation/NegotiatorTests.java b/src/test/java/com/capitati/omtc/core/negotiation/NegotiatorTests.java
new file mode 100644
index 0000000..2c94427
--- /dev/null
+++ b/src/test/java/com/capitati/omtc/core/negotiation/NegotiatorTests.java
@@ -0,0 +1,248 @@
+package com.capitati.omtc.core.negotiation;
+
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+import org.jmock.Expectations;
+import org.jmock.Mockery;
+import org.jmock.integration.junit4.JUnit4Mockery;
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+
+public class NegotiatorTests {
+  public Mockery mockery;
+  public IServiceResourceCapability resourceOne;
+  public IServiceResourceCapability resourceTwo;
+  public IServiceResourceCapability resourceThree;
+  public IServiceResourceCapability resourceFour;
+  public IFeatureCapability featureOne;
+  public IFeatureCapability featureTwo;
+  public IPrerequisiteCapability prereq;
+  public List<IServiceResourceCapability> resources;
+  public Set<IFeatureCapability> features;
+
+  @Before
+  public void setUp() {
+    mockery = new JUnit4Mockery();
+    resourceOne = mockery.mock(IServiceResourceCapability.class, "resourceOne");
+    resourceTwo = mockery.mock(IServiceResourceCapability.class, "resourceTwo");
+    resourceThree = mockery.mock(IServiceResourceCapability.class, "resourceThree");
+    resourceFour = mockery.mock(IServiceResourceCapability.class, "resourceFour");
+    featureOne = mockery.mock(IFeatureCapability.class, "featureOne");
+    featureTwo = mockery.mock(IFeatureCapability.class, "featureTwo");
+    prereq = mockery.mock(IPrerequisiteCapability.class, "prereqOne");
+
+    resources =
+        new ArrayList<IServiceResourceCapability>() {
+          private static final long serialVersionUID = 1L;
+          {
+            add(resourceOne);
+            add(resourceTwo);
+            add(resourceThree);
+            add(resourceFour);
+          }};
+          
+    features =
+        new HashSet<IFeatureCapability>() {
+          private static final long serialVersionUID = 1L;
+          {
+            add(featureOne);
+            add(featureTwo);
+          }};
+  }
+
+  @Test
+  public void testNegotiation() throws SemanticVersionParseException {
+    final ISemanticVersion clientVersion = SemanticVersion.parseVersion("1.3.7");
+    final IResourceCapability clientResourceCapOne = new IResourceCapability() {
+      public Capability getName() {
+        return Capability.RES_FILE_XLIFF;
+      }
+      public String getLowerVersion() {
+        return "1.6";
+      }
+      public String getHigherVersion() {
+        return "2.0";
+      }
+    };
+    final IResourceCapability clientResourceCapTwo = new IResourceCapability() {
+      public Capability getName() {
+        return Capability.RES_FILE_XLIFF;
+      }
+      public String getLowerVersion() {
+        return "7.0";
+      }
+      public String getHigherVersion() {
+        return "10.0";
+      }
+    };
+    final IResourceCapability clientResourceCapThree = new IResourceCapability() {
+      public Capability getName() {
+        return Capability.RES_FILE_TMX;
+      }
+      public String getLowerVersion() {
+        return "0.8";
+      }
+      public String getHigherVersion() {
+        return "10.5";
+      }
+    };
+    final IResourceCapability clientResourceCapFour = new IResourceCapability() {
+      public Capability getName() {
+        return Capability.RES_FILE_TTX;
+      }
+      public String getLowerVersion() {
+        return "2.718";
+      }
+      public String getHigherVersion() {
+        return "3.141";
+      }
+    };
+    final Set<IResourceCapability> clientResourceCapabilities =
+        new HashSet<IResourceCapability>() {
+          private static final long serialVersionUID = 1L;
+          {
+            add(clientResourceCapOne);
+            add(clientResourceCapTwo);
+            add(clientResourceCapThree);
+            add(clientResourceCapFour);
+          }};
+
+    mockery.checking(new Expectations() {{
+      allowing(resourceOne).getName();
+      will(returnValue(Capability.RES_FILE_XLIFF));
+      allowing(resourceOne).getLowerVersion();
+      will(returnValue("1.5"));
+      allowing(resourceOne).getHigherVersion();
+      will(returnValue("2.3"));
+      allowing(resourceOne).compareVersion(with(clientResourceCapOne));
+      will(returnValue(0));
+      allowing(resourceOne).compareVersion(with(clientResourceCapTwo));
+      will(returnValue(1));
+      allowing(resourceOne).compareVersion(with(any(IResourceCapability.class)));
+      will(returnValue(-1));
+
+      allowing(resourceTwo).getName();
+      will(returnValue(Capability.RES_FILE_XLIFF));
+      allowing(resourceTwo).getLowerVersion();
+      will(returnValue("3.7"));
+      allowing(resourceTwo).getHigherVersion();
+      will(returnValue("4.2"));
+      allowing(resourceTwo).compareVersion(with(any(IResourceCapability.class)));
+      will(returnValue(-1));
+
+      allowing(resourceThree).getName();
+      will(returnValue(Capability.RES_FILE_TMX));
+      allowing(resourceThree).getLowerVersion();
+      will(returnValue("0.2"));
+      allowing(resourceThree).getHigherVersion();
+      will(returnValue("1.0"));
+      allowing(resourceThree).compareVersion(clientResourceCapThree);
+      will(returnValue(0));
+      allowing(resourceThree).compareVersion(with(any(IResourceCapability.class)));
+      will(returnValue(-1));
+
+      allowing(resourceFour).getName();
+      will(returnValue(Capability.RES_FILE_TBX));
+      allowing(resourceFour).getLowerVersion();
+      will(returnValue("0.8"));
+      allowing(resourceFour).getHigherVersion();
+      will(returnValue("10.5"));
+      allowing(resourceFour).compareVersion(with(any(IResourceCapability.class)));
+      will(returnValue(-1));
+
+      allowing(featureOne).getName();
+      will(returnValue(Capability.FET_RES_DOWNLOAD));
+      allowing(featureOne).getPrerequisiteCapabilities();
+      will(returnValue(new HashSet<IPrerequisiteCapability>()));
+
+      allowing(featureTwo).getName();
+      will(returnValue(Capability.FET_RES_UPLOAD));
+      allowing(featureTwo).getPrerequisiteCapabilities();
+      will(returnValue(new HashSet<IPrerequisiteCapability>() {
+        private static final long serialVersionUID = 1L;
+        {
+          add(new IPrerequisiteCapability() {
+            public Capability getName() {
+              return Capability.PRE_REQ_PAYMENT;
+            }
+          });
+        }}));
+    }});
+
+    final INegotiator negotiator = new Negotiator("1.5.1", resources, features);
+    final IClientCapabilityRequest request = new IClientCapabilityRequest() {
+      public IAPICapability getVersionCapability() {
+       return new IAPICapability() {
+         public Capability getName() {
+           return Capability.API_VERSION;
+         }
+         public ISemanticVersion getVersion() {
+           return clientVersion;
+         }
+       };
+      }
+      public Set<IResourceCapability> getResourceCapabilities() {
+        return clientResourceCapabilities;
+      }
+    };
+    final IClientCapabilityResponse response = negotiator.negotiate(request);
+
+    final Set<IResourceCapability> targetUnsupportedResources =
+        new HashSet<IResourceCapability>() {
+          private static final long serialVersionUID = 4358016718704699346L;
+          {
+            add(clientResourceCapTwo);
+            add(clientResourceCapFour);
+          }};
+
+    Assert.assertTrue(response.isClientAPISupported());
+    Assert.assertEquals(
+        targetUnsupportedResources,
+        response.getUnsupportedResourceCapabilities());
+    Assert.assertEquals(features, response.getFeatureCapabilities());
+  }
+
+  @Test
+  public void testAPIVersionNotSupported() throws SemanticVersionParseException {
+    final INegotiator negotiator = new Negotiator("1.5.1", null, null);
+    final IClientCapabilityRequest requestLow = new IClientCapabilityRequest() {
+      public IAPICapability getVersionCapability() {
+       return new IAPICapability() {
+         public Capability getName() {
+           return Capability.API_VERSION;
+         }
+         public ISemanticVersion getVersion() {
+           return new SemanticVersion(0, 9, 0, "alpha.1", "build.1234");
+         }
+       };
+      }
+      public Set<IResourceCapability> getResourceCapabilities() {
+        return new HashSet<IResourceCapability>();
+      }
+    };
+    final IClientCapabilityResponse responseLow = negotiator.negotiate(requestLow);
+    final IClientCapabilityRequest requestHigh = new IClientCapabilityRequest() {
+      public IAPICapability getVersionCapability() {
+       return new IAPICapability() {
+         public Capability getName() {
+           return Capability.API_VERSION;
+         }
+         public ISemanticVersion getVersion() {
+           return new SemanticVersion(2, 3, 7);
+         }
+       };
+      }
+      public Set<IResourceCapability> getResourceCapabilities() {
+        return new HashSet<IResourceCapability>();
+      }
+    };
+    final IClientCapabilityResponse responseHigh = negotiator.negotiate(requestHigh);
+    
+    Assert.assertFalse(responseLow.isClientAPISupported());
+    Assert.assertFalse(responseHigh.isClientAPISupported());
+  }
+}
diff --git a/src/test/java/com/capitati/omtc/core/negotiation/SemanticVersionComparatorTests.java b/src/test/java/com/capitati/omtc/core/negotiation/SemanticVersionComparatorTests.java
new file mode 100644
index 0000000..adff242
--- /dev/null
+++ b/src/test/java/com/capitati/omtc/core/negotiation/SemanticVersionComparatorTests.java
@@ -0,0 +1,528 @@
+package com.capitati.omtc.core.negotiation;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.apache.commons.lang3.tuple.ImmutablePair;
+import org.junit.Assert;
+import org.junit.Test;
+
+public class SemanticVersionComparatorTests {
+  private interface IVersionsWithChecker {
+    ISemanticVersion getLeftVersion();
+    ISemanticVersion getRightVersion();
+    boolean forwardCheck(int comparisonValue);
+    boolean backwardCheck(int comparisonValue);
+    SemanticVersionComponent getChangedComponent();
+  }
+
+  private static final List<ISemanticVersion> orderedVersions =
+      new ArrayList<ISemanticVersion>() {
+    private static final long serialVersionUID = 1L;
+    {
+      add(new SemanticVersion(1, 0, 0, "alpha", null));
+      add(new SemanticVersion(1, 0, 0, "alpha.1", null));
+      add(new SemanticVersion(1, 0, 0, "beta.2", null));
+      add(new SemanticVersion(1, 0, 0, "beta.11", null));
+      add(new SemanticVersion(1, 0, 0, "rc.1", null));
+      add(new SemanticVersion(1, 0, 0, "rc.1", "build.1"));
+      add(new SemanticVersion(1, 0, 0, "rc.2", null));
+      add(new SemanticVersion(1, 0, 0));
+      add(new SemanticVersion(1, 0, 1));
+      add(new SemanticVersion(1, 1, 2));
+      add(new SemanticVersion(2, 0, 0));
+      add(new SemanticVersion(2, 0, 0, null, "0.3.7"));
+      add(new SemanticVersion(2, 3, 7, null, "build"));
+      add(new SemanticVersion(2, 3, 7, null, "build.2.b8f12d7"));
+      add(new SemanticVersion(2, 3, 7, null, "build.11.e0f985a"));
+  }};
+
+  @Test
+  public void testComparatorWithLexicalOrdering() {
+    for(int idx = 0; idx < orderedVersions.size() - 1; idx++) {
+      final ISemanticVersion one = orderedVersions.get(idx);
+      final ISemanticVersion two = orderedVersions.get(idx + 1);
+      
+      System.err.printf(
+          "Version [%s] and [%s]...%s",
+          one,
+          two,
+          System.lineSeparator());
+      
+      Assert.assertTrue(
+          String.format(
+              "Semantic version [%s] is greater than [%s]",
+              one, two),
+          SemanticVersionComparator.compare(one, two).getLeft() < 0);
+      Assert.assertTrue(
+          String.format(
+              "Semantic version [%s] is less than [%s]",
+              two, one),
+          SemanticVersionComparator.compare(two, one).getLeft() > 0);
+      Assert.assertTrue(
+          String.format(
+              "Semantic version [%s] is not equal to itself!", one),
+          SemanticVersionComparator.compare(one, one).getLeft() == 0);
+      Assert.assertTrue(
+          String.format(
+              "Semantic version [%s] is not equal to itself!", two),
+          SemanticVersionComparator.compare(two, two).getLeft() == 0);
+    }
+  }
+
+  /*
+   * Versions with both pre-release and build
+   */
+  private static final List<IVersionsWithChecker> versionsWithPreReleaseAndBuild =
+      new ArrayList<IVersionsWithChecker>() {
+    private static final long serialVersionUID = 1L;
+    {
+      add(new IVersionsWithChecker() {
+        public ISemanticVersion getLeftVersion() {
+          return new SemanticVersion(1, 0, 0, "rc.1", "build.1");
+        }
+        public ISemanticVersion getRightVersion() {
+          // Arrrgh, v4!
+          return new SemanticVersion(4, 0, 0, "rc.1", "build.2.b8f12d7");
+        }
+        public boolean forwardCheck(int comparisonValue) {
+          return (comparisonValue < 0);
+        }
+        public boolean backwardCheck(int comparisonValue) {
+          return (comparisonValue > 0);
+        }
+        public SemanticVersionComponent getChangedComponent() {
+          return SemanticVersionComponent.MAJOR_VERSION;
+        }
+      });
+
+      add(new IVersionsWithChecker() {
+        public ISemanticVersion getLeftVersion() {
+          return new SemanticVersion(1, 0, 0, "rc.1", "build.1");
+        }
+        public ISemanticVersion getRightVersion() {
+          return new SemanticVersion(1, 5, 0, "rc.1", "build.2.b8f12d7");
+        }
+        public boolean forwardCheck(int comparisonValue) {
+          return (comparisonValue < 0);
+        }
+        public boolean backwardCheck(int comparisonValue) {
+          return (comparisonValue > 0);
+        }
+        public SemanticVersionComponent getChangedComponent() {
+          return SemanticVersionComponent.MINOR_VERSION;
+        }
+      });
+
+      add(new IVersionsWithChecker() {
+        public ISemanticVersion getLeftVersion() {
+          return new SemanticVersion(1, 0, 0, "rc.1", "build.1");
+        }
+        public ISemanticVersion getRightVersion() {
+          return new SemanticVersion(1, 0, 8, "rc.1", "build.2.b8f12d7");
+        }
+        public boolean forwardCheck(int comparisonValue) {
+          return (comparisonValue < 0);
+        }
+        public boolean backwardCheck(int comparisonValue) {
+          return (comparisonValue > 0);
+        }
+        public SemanticVersionComponent getChangedComponent() {
+          return SemanticVersionComponent.PATCH_VERSION;
+        }
+      });
+
+      add(new IVersionsWithChecker() {
+        public ISemanticVersion getLeftVersion() {
+          return new SemanticVersion(1, 0, 0, "rc.1", "build.1");
+        }
+        public ISemanticVersion getRightVersion() {
+          return new SemanticVersion(1, 0, 0, "rc.1", "build.2.b8f12d7");
+        }
+        public boolean forwardCheck(int comparisonValue) {
+          return (comparisonValue < 0);
+        }
+        public boolean backwardCheck(int comparisonValue) {
+          return (comparisonValue > 0);
+        }
+        public SemanticVersionComponent getChangedComponent() {
+          return SemanticVersionComponent.PRE_RELEASE_AND_BUILD_VERSION;
+        }
+      });
+
+      add(new IVersionsWithChecker() {
+        public ISemanticVersion getLeftVersion() {
+          return new SemanticVersion(1, 0, 0, "rc.1", "build.1");
+        }
+        public ISemanticVersion getRightVersion() {
+          return new SemanticVersion(1, 0, 0, "rc.2", "build.2.b8f12d7");
+        }
+        public boolean forwardCheck(int comparisonValue) {
+          return (comparisonValue < 0);
+        }
+        public boolean backwardCheck(int comparisonValue) {
+          return (comparisonValue > 0);
+        }
+        public SemanticVersionComponent getChangedComponent() {
+          return SemanticVersionComponent.PRE_RELEASE_AND_BUILD_VERSION;
+        }
+      });
+
+      add(new IVersionsWithChecker() {
+        public ISemanticVersion getLeftVersion() {
+          return new SemanticVersion(1, 0, 0, "rc.1", "build.1");
+        }
+        public ISemanticVersion getRightVersion() {
+          return new SemanticVersion(1, 0, 0, "rc.2", "build.1");
+        }
+        public boolean forwardCheck(int comparisonValue) {
+          return (comparisonValue < 0);
+        }
+        public boolean backwardCheck(int comparisonValue) {
+          return (comparisonValue > 0);
+        }
+        public SemanticVersionComponent getChangedComponent() {
+          return SemanticVersionComponent.PRE_RELEASE_AND_BUILD_VERSION;
+        }
+      });
+  }};
+  
+  @Test
+  public void testPreReleaseAndBuildComponentOrdering() {
+    runVersionsWithCheckTest(versionsWithPreReleaseAndBuild);
+  }
+
+  /*
+   * These versions invoke the true, true code path for pre-release and
+   * build comparisons.
+   */
+  private static final List<IVersionsWithChecker> versionWithNullComponents =
+  new ArrayList<IVersionsWithChecker>() {
+    private static final long serialVersionUID = 1L;
+    {
+      add(new IVersionsWithChecker() {
+        public ISemanticVersion getLeftVersion() {
+          return new SemanticVersion(1, 0, 0);
+        }
+        public ISemanticVersion getRightVersion() {
+          return new SemanticVersion(1, 0, 1);
+        }
+        public boolean forwardCheck(int comparisonValue) {
+          return (comparisonValue < 0);
+        }
+        public boolean backwardCheck(int comparisonValue) {
+          return (comparisonValue > 0);
+        }
+        public SemanticVersionComponent getChangedComponent() {
+          return SemanticVersionComponent.PATCH_VERSION;
+        }
+      });
+
+      add(new IVersionsWithChecker() {
+        public ISemanticVersion getLeftVersion() {
+          return new SemanticVersion(1, 0, 0);
+        }
+        public ISemanticVersion getRightVersion() {
+          return new SemanticVersion(1, 2, 0);
+        }
+        public boolean forwardCheck(int comparisonValue) {
+          return (comparisonValue < 0);
+        }
+        public boolean backwardCheck(int comparisonValue) {
+          return (comparisonValue > 0);
+        }
+        public SemanticVersionComponent getChangedComponent() {
+          return SemanticVersionComponent.MINOR_VERSION;
+        }        
+      });
+
+      add(new IVersionsWithChecker() {
+        public ISemanticVersion getLeftVersion() {
+          return new SemanticVersion(1, 0, 0);
+        }
+        public ISemanticVersion getRightVersion() {
+          return new SemanticVersion(3, 2, 0);
+        }
+        public boolean forwardCheck(int comparisonValue) {
+          return (comparisonValue < 0);
+        }
+        public boolean backwardCheck(int comparisonValue) {
+          return (comparisonValue > 0);
+        }
+        public SemanticVersionComponent getChangedComponent() {
+          return SemanticVersionComponent.MAJOR_VERSION;
+        }        
+      });
+
+      add(new IVersionsWithChecker() {
+        public ISemanticVersion getLeftVersion() {
+          return new SemanticVersion(1, 0, 0);
+        }
+        public ISemanticVersion getRightVersion() {
+          return new SemanticVersion(1, 0, 0, "rc.1", null);
+        }
+        public boolean forwardCheck(int comparisonValue) {
+          return (comparisonValue > 0);
+        }
+        public boolean backwardCheck(int comparisonValue) {
+          return (comparisonValue < 0);
+        }
+        public SemanticVersionComponent getChangedComponent() {
+          return SemanticVersionComponent.PRE_RELEASE_AND_BUILD_VERSION;
+        }
+      });
+
+      add(new IVersionsWithChecker() {
+        public ISemanticVersion getLeftVersion() {
+          return new SemanticVersion(1, 0, 0);
+        }
+        public ISemanticVersion getRightVersion() {
+          return new SemanticVersion(1, 0, 0, null, "build.2");
+        }
+        public boolean forwardCheck(int comparisonValue) {
+          return (comparisonValue < 0);
+        }
+        public boolean backwardCheck(int comparisonValue) {
+          return (comparisonValue < 0);
+        }
+        public SemanticVersionComponent getChangedComponent() {
+          return SemanticVersionComponent.PRE_RELEASE_AND_BUILD_VERSION;
+        }
+      });
+
+      add(new IVersionsWithChecker() {
+        public ISemanticVersion getLeftVersion() {
+          return new SemanticVersion(1, 0, 0);
+        }
+        public ISemanticVersion getRightVersion() {
+          return new SemanticVersion(1, 0, 0, "rc.1", "build.2");
+        }
+        public boolean forwardCheck(int comparisonValue) {
+          return (comparisonValue > 0);
+        }
+        public boolean backwardCheck(int comparisonValue) {
+          return (comparisonValue < 0);
+        }
+        public SemanticVersionComponent getChangedComponent() {
+          return SemanticVersionComponent.PRE_RELEASE_AND_BUILD_VERSION;
+        }
+      });
+
+      add(new IVersionsWithChecker() {
+        public ISemanticVersion getLeftVersion() {
+          return new SemanticVersion(1, 0, 0);
+        }
+        public ISemanticVersion getRightVersion() {
+          return new SemanticVersion(1, 0, 0);
+        }
+        public boolean forwardCheck(int comparisonValue) {
+          return (comparisonValue == 0);
+        }
+        public boolean backwardCheck(int comparisonValue) {
+          return forwardCheck(comparisonValue);
+        }
+        public SemanticVersionComponent getChangedComponent() {
+          return SemanticVersionComponent.INVALID;
+        }        
+      });
+
+      add(new IVersionsWithChecker() {
+        public ISemanticVersion getLeftVersion() {
+          return new SemanticVersion(1, 0, 0, "rc.1", null);
+        }
+        public ISemanticVersion getRightVersion() {
+          return new SemanticVersion(1, 0, 0);
+        }
+        public boolean forwardCheck(int comparisonValue) {
+          return (comparisonValue < 0);
+        }
+        public boolean backwardCheck(int comparisonValue) {
+          return (comparisonValue > 0);
+        }
+        public SemanticVersionComponent getChangedComponent() {
+          return SemanticVersionComponent.PRE_RELEASE_AND_BUILD_VERSION;
+        }
+      });
+
+      add(new IVersionsWithChecker() {
+        public ISemanticVersion getLeftVersion() {
+          return new SemanticVersion(1, 0, 0, null, "build.2");
+        }
+        public ISemanticVersion getRightVersion() {
+          return new SemanticVersion(1, 0, 0);
+        }
+        public boolean forwardCheck(int comparisonValue) {
+          return (comparisonValue > 0);
+        }
+        public boolean backwardCheck(int comparisonValue) {
+          return (comparisonValue < 0);
+        }
+        public SemanticVersionComponent getChangedComponent() {
+          return SemanticVersionComponent.PRE_RELEASE_AND_BUILD_VERSION;
+        }
+      });
+
+      add(new IVersionsWithChecker() {
+        public ISemanticVersion getLeftVersion() {
+          return new SemanticVersion(1, 0, 0, "rc.1", "build.2");
+        }
+        public ISemanticVersion getRightVersion() {
+          return new SemanticVersion(1, 0, 0);
+        }
+        public boolean forwardCheck(int comparisonValue) {
+          return (comparisonValue < 0);
+        }
+        public boolean backwardCheck(int comparisonValue) {
+          return (comparisonValue > 0);
+        }
+        public SemanticVersionComponent getChangedComponent() {
+          return SemanticVersionComponent.PRE_RELEASE_AND_BUILD_VERSION;
+        }
+      });
+
+      add(new IVersionsWithChecker() {
+        public ISemanticVersion getLeftVersion() {
+          return new SemanticVersion(1, 0, 0, "beta.11", null);
+        }
+        public ISemanticVersion getRightVersion() {
+          return new SemanticVersion(1, 0, 0, null, "build.11.e0f985a");
+        }
+        public boolean forwardCheck(int comparisonValue) {
+          return (comparisonValue < 0);
+        }
+        public boolean backwardCheck(int comparisonValue) {
+          return (comparisonValue > 0);
+        }
+        public SemanticVersionComponent getChangedComponent() {
+          return SemanticVersionComponent.PRE_RELEASE_AND_BUILD_VERSION;
+        }
+      });
+
+      add(new IVersionsWithChecker() {
+        public ISemanticVersion getLeftVersion() {
+          return new SemanticVersion(1, 0, 0, null, "build.1");
+        }
+        public ISemanticVersion getRightVersion() {
+          return new SemanticVersion(1, 0, 0, null, "build.2");
+        }
+        public boolean forwardCheck(int comparisonValue) {
+          return (comparisonValue < 0);
+        }
+        public boolean backwardCheck(int comparisonValue) {
+          return (comparisonValue > 0);
+        }
+        public SemanticVersionComponent getChangedComponent() {
+          return SemanticVersionComponent.PRE_RELEASE_AND_BUILD_VERSION;
+        }        
+      });
+
+      add(new IVersionsWithChecker() {
+        public ISemanticVersion getLeftVersion() {
+          return new SemanticVersion(1, 0, 0, null, "build.2");
+        }
+        public ISemanticVersion getRightVersion() {
+          return new SemanticVersion(1, 0, 0, null, "build.1");
+        }
+        public boolean forwardCheck(int comparisonValue) {
+          return (comparisonValue > 0);
+        }
+        public boolean backwardCheck(int comparisonValue) {
+          return (comparisonValue < 0);
+        }
+        public SemanticVersionComponent getChangedComponent() {
+          return SemanticVersionComponent.PRE_RELEASE_AND_BUILD_VERSION;
+        }        
+      });
+
+      add(new IVersionsWithChecker() {
+        public ISemanticVersion getLeftVersion() {
+          return new SemanticVersion(1, 0, 0, "rc.1", "build.1");
+        }
+        public ISemanticVersion getRightVersion() {
+          return new SemanticVersion(1, 0, 0, null, "build.2.b8f12d7");
+        }
+        public boolean forwardCheck(int comparisonValue) {
+          return (comparisonValue < 0);
+        }
+        public boolean backwardCheck(int comparisonValue) {
+          return (comparisonValue > 0);
+        }
+        public SemanticVersionComponent getChangedComponent() {
+          return SemanticVersionComponent.PRE_RELEASE_AND_BUILD_VERSION;
+        }
+      });
+  }};
+
+  @Test
+  public void testVersionsWithNullPreReleaseOrBuild() {
+    runVersionsWithCheckTest(versionWithNullComponents);
+  }
+
+  @Test
+  public void testVersionParser() throws SemanticVersionParseException {
+    final List<ISemanticVersion> versions = new ArrayList<ISemanticVersion>() {
+      private static final long serialVersionUID = -1726840289543320508L;
+    {
+      add(new SemanticVersion(4, 5, 9));
+      add(new SemanticVersion(3, 6, 2, "rc.2.deadbeef", null));
+      add(new SemanticVersion(10, 0, 8, null, "build.667"));
+      add(new SemanticVersion(0, 5, 10, "rc.10.a4b56", "build.b39de2"));
+    }};
+
+    for(ISemanticVersion version : versions) {
+      Assert.assertEquals(
+          String.format("Failed to parse version [%s]", version),
+          SemanticVersion.parseVersion(version.toString()),
+          version);
+    }
+  }
+
+  @Test(expected = IllegalArgumentException.class)
+  public void testNegativeMajorVersionConstruction() {
+    @SuppressWarnings("unused")
+    final ISemanticVersion sv = new SemanticVersion(-1, 5, 8);
+  }
+
+  @Test(expected = IllegalArgumentException.class)
+  public void testNegativeMinorVersionConstruction() {
+    @SuppressWarnings("unused")
+    final ISemanticVersion sv = new SemanticVersion(1, -5, 8);
+  }
+
+  @Test(expected = IllegalArgumentException.class)
+  public void testNegativePatchVersionConstruction() {
+    @SuppressWarnings("unused")
+    final ISemanticVersion sv = new SemanticVersion(1, 5, -8);
+  }
+
+  private void runVersionsWithCheckTest(
+      final List<IVersionsWithChecker> vwcCollection) {
+    for(IVersionsWithChecker vwc : vwcCollection) {
+      System.err.printf(
+          "Version [%s] and [%s]...%s",
+          vwc.getLeftVersion(),
+          vwc.getRightVersion(),
+          System.lineSeparator());
+
+      final ImmutablePair<Integer, SemanticVersionComponent> comparison =
+          SemanticVersionComparator.compare(
+              vwc.getLeftVersion(),
+              vwc.getRightVersion());
+
+      Assert.assertTrue(
+          String.format(
+              "Semantic versions [%s] and [%s] failed check.",
+              vwc.getLeftVersion(), vwc.getRightVersion()),
+          vwc.forwardCheck(comparison.getLeft()));
+      Assert.assertTrue(
+          String.format(
+              "Semantic versions [%s] and [%s] failed expected component change:" +
+              "got [%s], expected [%s]",
+              vwc.getLeftVersion(),
+              vwc.getRightVersion(),
+              comparison.getRight(),
+              vwc.getChangedComponent()),
+          comparison.getRight() == vwc.getChangedComponent());
+    }
+  }
+}
diff --git a/src/test/java/com/capitati/omtc/core/negotiation/SemanticVersionTests.java b/src/test/java/com/capitati/omtc/core/negotiation/SemanticVersionTests.java
new file mode 100644
index 0000000..1866fc3
--- /dev/null
+++ b/src/test/java/com/capitati/omtc/core/negotiation/SemanticVersionTests.java
@@ -0,0 +1,37 @@
+package com.capitati.omtc.core.negotiation;
+
+import java.util.ArrayList;
+import java.util.Collection;
+
+import junit.framework.Assert;
+
+import org.junit.Test;
+
+public class SemanticVersionTests {
+  private static final Collection<ISemanticVersion> versions =
+      new ArrayList<ISemanticVersion>() {
+    private static final long serialVersionUID = 1L;
+    {
+      add(new SemanticVersion(1, 0, 0, "alpha", null));
+      add(new SemanticVersion(1, 0, 0, "alpha.1", null));
+      add(new SemanticVersion(1, 0, 0, "beta.2", null));
+      add(new SemanticVersion(1, 0, 0, "beta.11", null));
+      add(new SemanticVersion(1, 0, 0, "rc.1", null));
+      add(new SemanticVersion(1, 0, 0, "rc.1", "build.1"));
+      add(new SemanticVersion(1, 0, 0));
+      add(new SemanticVersion(1, 0, 0, null, "0.3.7"));
+      add(new SemanticVersion(1, 3, 7, null, "build"));
+      add(new SemanticVersion(1, 3, 7, null, "build.2.b8f12d7"));
+      add(new SemanticVersion(1, 3, 7, null, "build.11.e0f985a"));
+  }};
+
+  @Test
+  public void testSemanticVersionParsing()
+  throws SemanticVersionParseException {
+    for(ISemanticVersion target : versions) {
+      final ISemanticVersion version =
+        SemanticVersion.parseVersion(target.toString());
+      Assert.assertEquals(target, version);
+    }
+  }
+}
diff --git a/src/test/java/com/capitati/omtc/core/session/PrimaryResource.java b/src/test/java/com/capitati/omtc/core/session/PrimaryResource.java
new file mode 100644
index 0000000..dedf86b
--- /dev/null
+++ b/src/test/java/com/capitati/omtc/core/session/PrimaryResource.java
@@ -0,0 +1,75 @@
+package com.capitati.omtc.core.session;
+
+import java.net.URI;
+import java.util.Date;
+import java.util.UUID;
+
+import com.capitati.omtc.core.resources.IPrimaryResource;
+
+public class PrimaryResource implements IPrimaryResource {
+  final UUID resourceId;
+  final URI resourceUri;
+  final Date resourceBirthDate;
+
+  public PrimaryResource(
+      final UUID resourceId,
+      final URI resourceUri,
+      final Date resourceBirthDate) {
+    super();
+    this.resourceId = resourceId;
+    this.resourceUri = resourceUri;
+    this.resourceBirthDate = resourceBirthDate;
+  }
+
+  public UUID getIdentifier() {
+    return resourceId;
+  }
+
+  public URI getURI() {
+    return resourceUri;
+  }
+
+  public Date getBirthDate() {
+    return resourceBirthDate;
+  }
+
+  @Override
+  public int hashCode() {
+    final int prime = 31;
+    int result = 1;
+    result = prime * result
+        + ((resourceBirthDate == null) ? 0 : resourceBirthDate.hashCode());
+    result = prime * result
+        + ((resourceId == null) ? 0 : resourceId.hashCode());
+    result = prime * result
+        + ((resourceUri == null) ? 0 : resourceUri.hashCode());
+    return result;
+  }
+
+  @Override
+  public boolean equals(Object obj) {
+    if(this == obj)
+      return true;
+    if(obj == null)
+      return false;
+    if(getClass() != obj.getClass())
+      return false;
+    PrimaryResource other = (PrimaryResource) obj;
+    if(resourceBirthDate == null) {
+      if(other.resourceBirthDate != null)
+        return false;
+    } else if(!resourceBirthDate.equals(other.resourceBirthDate))
+      return false;
+    if(resourceId == null) {
+      if(other.resourceId != null)
+        return false;
+    } else if(!resourceId.equals(other.resourceId))
+      return false;
+    if(resourceUri == null) {
+      if(other.resourceUri != null)
+        return false;
+    } else if(!resourceUri.equals(other.resourceUri))
+      return false;
+    return true;
+  }
+}
diff --git a/src/test/java/com/capitati/omtc/core/session/ResourceUploadDelegate.java b/src/test/java/com/capitati/omtc/core/session/ResourceUploadDelegate.java
new file mode 100644
index 0000000..208122f
--- /dev/null
+++ b/src/test/java/com/capitati/omtc/core/session/ResourceUploadDelegate.java
@@ -0,0 +1,79 @@
+package com.capitati.omtc.core.session;
+
+import java.io.IOException;
+import java.net.URI;
+import java.util.Date;
+import java.util.UUID;
+
+import org.apache.commons.lang3.ArrayUtils;
+
+import com.capitati.omtc.core.resources.IResource;
+import com.capitati.omtc.core.resources.IResourceReader;
+import com.capitati.omtc.core.resources.IResourceWriter;
+
+public class ResourceUploadDelegate implements IResourceTransferDelegate {
+  private final IResource resource;
+  private final String source;
+  private byte[] destination;
+
+  public ResourceUploadDelegate(
+      final String theSource,
+      final UUID theResourceId,
+      final URI theResourceUri,
+      final Date theResourceBirthDate) {
+    source = theSource;
+    resource = new PrimaryResource(
+        theResourceId, theResourceUri, theResourceBirthDate);
+  }
+
+  public IResourceReader getResourceReader(final ISession theInvokingSession)
+  throws Exception {
+    return new IResourceReader() {
+      private final byte[] readerSource = source.getBytes();
+      private int noBytesRead = 0;
+
+      public int read(final byte[] buffer) throws IOException {
+        if(noBytesRead >= readerSource.length) {
+          return -1;
+        }
+
+        int bytesRead = 0;
+        for(int idx = 0;
+            (idx < buffer.length) && ((noBytesRead + bytesRead) < readerSource.length);
+            idx++) {
+          buffer[idx] = readerSource[noBytesRead + idx];
+          bytesRead += 1;
+        }
+        
+        noBytesRead += bytesRead;
+
+        return bytesRead;
+      }
+
+      public void close() throws IOException {
+      }
+    };
+  }
+
+  public IResourceWriter getResourceWriter(final ISession theInvokingSession)
+  throws Exception {
+    return new IResourceWriter() {
+      public void write(byte[] chunk, int chunkLength) throws IOException {
+        destination = ArrayUtils.addAll(
+            destination,
+            ArrayUtils.subarray(chunk, 0, chunkLength));
+      }
+
+      public void close() throws IOException {
+      }
+    };
+  }
+
+  public IResource getResource(final ISession theInvokingSession) {
+    return resource;
+  }
+
+  public byte[] getDestination() {
+    return destination;
+  }
+}
diff --git a/src/test/java/com/capitati/omtc/core/session/SessionTestException.java b/src/test/java/com/capitati/omtc/core/session/SessionTestException.java
new file mode 100644
index 0000000..372a8ef
--- /dev/null
+++ b/src/test/java/com/capitati/omtc/core/session/SessionTestException.java
@@ -0,0 +1,7 @@
+package com.capitati.omtc.core.session;
+
+import java.io.IOException;
+
+public class SessionTestException extends IOException {
+  private static final long serialVersionUID = 7413491732377268653L;
+}
diff --git a/src/test/java/com/capitati/omtc/core/session/SessionTests.java b/src/test/java/com/capitati/omtc/core/session/SessionTests.java
new file mode 100644
index 0000000..986a696
--- /dev/null
+++ b/src/test/java/com/capitati/omtc/core/session/SessionTests.java
@@ -0,0 +1,203 @@
+package com.capitati.omtc.core.session;
+
+import java.net.URI;
+import java.net.URISyntaxException;
+import java.util.Date;
+import java.util.Set;
+import java.util.UUID;
+import java.util.concurrent.AbstractExecutorService;
+import java.util.concurrent.ArrayBlockingQueue;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.Future;
+import java.util.concurrent.ThreadPoolExecutor;
+import java.util.concurrent.TimeUnit;
+
+import org.jmock.Expectations;
+import org.jmock.Mockery;
+import org.jmock.integration.junit4.JUnit4Mockery;
+import org.junit.After;
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+
+import com.capitati.omtc.core.notification.IResourceUploadObserver;
+import com.capitati.omtc.core.resources.IResource;
+import com.capitati.omtc.core.resources.IResourceReader;
+import com.capitati.omtc.core.resources.IResourceWriter;
+import com.google.common.base.Predicate;
+
+public class SessionTests {
+  class TestSession extends Session {
+    protected TestSession(
+        final UUID theIdentifier,
+        final AbstractExecutorService theDelegationExecutorService,
+        final int bufferSize) {
+      super(theIdentifier, theDelegationExecutorService, bufferSize);
+    }
+
+    public Set<IResource> retrieveResources(final Predicate<IResource> theFilter)
+    throws Exception {
+      return null;
+    }
+
+    public void removeResource(final IResource resource) throws Exception {
+    }
+  }
+
+  private static final String MESSAGE =
+      "Whose was it? His who is gone. " +
+      "Who shall have it? He who will come. " +
+      "Where was the sun? Over the oak. " +
+      "Where was the shadow? Under the elm. " +
+      "How was it stepped? North by ten and by ten, east by five and by five, " +
+      "south by two and by two, west by one and by one, and so under. " +
+      "What shall we give for it? All that is ours. " +
+      "Why should we give it? For the sake of the trust.";
+
+  private final UUID resourceId = UUID.randomUUID();
+  private final Date resourceBirthDate = new Date();
+
+  private URI resourceUri;
+  private Mockery mockery;
+  private AbstractExecutorService executor;
+  private Session session;
+  
+  @Before
+  public void setUp() throws URISyntaxException {
+    mockery = new JUnit4Mockery();
+    resourceUri = new URI("test://some_resource_or_other");
+    executor =  new ThreadPoolExecutor(
+        1,
+        1,
+        0,
+        TimeUnit.SECONDS, new ArrayBlockingQueue<Runnable>(1));
+    session = new TestSession(UUID.randomUUID(), executor, MESSAGE.length() / 4);
+  }
+
+  @After
+  public void tearDown() {
+    executor.shutdown();
+  }
+  
+  @Test
+  public void testSuccessfulUpload() throws Exception {
+    final IResourceTransferDelegate delegate = new ResourceUploadDelegate(
+        MESSAGE,
+        resourceId,
+        resourceUri,
+        resourceBirthDate);
+    final IResourceUploadObserver observer =
+        mockery.mock(IResourceUploadObserver.class, "successUploadObserver");
+    final IResource targetResource = delegate.getResource(session);
+    
+    mockery.checking(new Expectations() {{
+      oneOf(observer).onSuccess(
+          with(equal(session)),
+          with(equal(targetResource)));
+    }});
+
+    final Future<IResource> futureResource = session.uploadResource(delegate, observer);
+    final IResource resource = futureResource.get();
+
+    Assert.assertSame("Wrong resource", targetResource, resource);
+  }
+
+  @Test(expected = SessionTestException.class)
+  public void testReaderReadFailureOnUpload() throws Throwable {
+    final Exception targetException = new SessionTestException();
+    final IResourceReader resourceReader =
+        mockery.mock(IResourceReader.class, "resourceReader");
+    final IResourceWriter resourceWriter =
+        mockery.mock(IResourceWriter.class, "resourceWriter");
+    final IResourceTransferDelegate delegate =
+        mockery.mock(IResourceTransferDelegate.class, "badUploadDelegate");
+    final IResourceUploadObserver observer =
+        mockery.mock(IResourceUploadObserver.class, "badUploadObserver");
+    final IResource resource =
+        mockery.mock(IResource.class, "badResource");
+
+    mockery.checking(new Expectations() {{
+      allowing(delegate).getResource(with(equal(session)));
+      will(returnValue(resource));
+
+      oneOf(resourceReader).read(with(any(byte[].class)));
+      will(throwException(targetException));
+
+      oneOf(resourceReader).close();
+
+      oneOf(resourceWriter).close();
+
+      oneOf(delegate).getResourceReader(with(equal(session)));
+      will(returnValue(resourceReader));
+
+      oneOf(delegate).getResourceWriter(with(equal(session)));
+      will(returnValue(resourceWriter));
+      
+      oneOf(observer).onError(
+          with(equal(session)),
+          with(equal(resource)),
+          with(equal(targetException)));
+    }});
+
+    final Future<IResource> futureResource =
+        session.uploadResource(delegate, observer);
+    
+    try {
+      @SuppressWarnings("unused")
+      final IResource future = futureResource.get();
+    } catch(final ExecutionException ex) {
+      throw ex.getCause();
+    }
+  }
+
+  @Test(expected = SessionTestException.class)
+  public void testWriterWriteFailureOnUpload() throws Throwable {
+    final Exception targetException = new SessionTestException();
+    final IResourceReader resourceReader =
+        mockery.mock(IResourceReader.class, "resourceReader");
+    final IResourceWriter resourceWriter =
+        mockery.mock(IResourceWriter.class, "resourceWriter");
+    final IResourceTransferDelegate delegate =
+        mockery.mock(IResourceTransferDelegate.class, "badUploadDelegate");
+    final IResourceUploadObserver observer =
+        mockery.mock(IResourceUploadObserver.class, "badUploadObserver");
+    final IResource resource =
+        mockery.mock(IResource.class, "badResource");
+
+    mockery.checking(new Expectations() {{
+      allowing(delegate).getResource(with(equal(session)));
+      will(returnValue(resource));
+
+      oneOf(resourceReader).read(with(any(byte[].class)));
+      will(returnValue(7));
+
+      oneOf(resourceReader).close();
+
+      oneOf(resourceWriter).write(with(any(byte[].class)), with(any(int.class)));
+      will(throwException(targetException));
+
+      oneOf(resourceWriter).close();
+
+      oneOf(delegate).getResourceReader(with(equal(session)));
+      will(returnValue(resourceReader));
+
+      oneOf(delegate).getResourceWriter(with(equal(session)));
+      will(returnValue(resourceWriter));
+
+      oneOf(observer).onError(
+          with(equal(session)),
+          with(equal(resource)),
+          with(equal(targetException)));
+    }});
+
+    final Future<IResource> futureResource =
+        session.uploadResource(delegate, observer);
+    
+    try {
+      @SuppressWarnings("unused")
+      final IResource future = futureResource.get();
+    } catch(final ExecutionException ex) {
+      throw ex.getCause();
+    }
+  }
+}