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Diffstat (limited to 'src/core/Search/Function/DocValues.cs')
| -rw-r--r-- | src/core/Search/Function/DocValues.cs | 206 |
1 files changed, 206 insertions, 0 deletions
diff --git a/src/core/Search/Function/DocValues.cs b/src/core/Search/Function/DocValues.cs new file mode 100644 index 0000000..fcb5e7d --- /dev/null +++ b/src/core/Search/Function/DocValues.cs @@ -0,0 +1,206 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You under the Apache License, Version 2.0 + * (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +using System; + +using Explanation = Lucene.Net.Search.Explanation; + +namespace Lucene.Net.Search.Function +{ + + /// <summary> Expert: represents field values as different types. + /// Normally created via a + /// <see cref="Lucene.Net.Search.Function.ValueSource">ValueSuorce</see> + /// for a particular field and reader. + /// + /// <p/><font color="#FF0000"> + /// WARNING: The status of the <b>Search.Function</b> package is experimental. + /// The APIs introduced here might change in the future and will not be + /// supported anymore in such a case.</font> + /// + /// + /// </summary> + public abstract class DocValues + { + /* + * DocValues is distinct from ValueSource because + * there needs to be an object created at query evaluation time that + * is not referenced by the query itself because: + * - Query objects should be MT safe + * - For caching, Query objects are often used as keys... you don't + * want the Query carrying around big objects + */ + + /// <summary> Return doc value as a float. + /// <p/>Mandatory: every DocValues implementation must implement at least this method. + /// </summary> + /// <param name="doc">document whose float value is requested. + /// </param> + public abstract float FloatVal(int doc); + + /// <summary> Return doc value as an int. + /// <p/>Optional: DocValues implementation can (but don't have to) override this method. + /// </summary> + /// <param name="doc">document whose int value is requested. + /// </param> + public virtual int IntVal(int doc) + { + return (int) FloatVal(doc); + } + + /// <summary> Return doc value as a long. + /// <p/>Optional: DocValues implementation can (but don't have to) override this method. + /// </summary> + /// <param name="doc">document whose long value is requested. + /// </param> + public virtual long LongVal(int doc) + { + return (long) FloatVal(doc); + } + + /// <summary> Return doc value as a double. + /// <p/>Optional: DocValues implementation can (but don't have to) override this method. + /// </summary> + /// <param name="doc">document whose double value is requested. + /// </param> + public virtual double DoubleVal(int doc) + { + return (double) FloatVal(doc); + } + + /// <summary> Return doc value as a string. + /// <p/>Optional: DocValues implementation can (but don't have to) override this method. + /// </summary> + /// <param name="doc">document whose string value is requested. + /// </param> + public virtual System.String StrVal(int doc) + { + return FloatVal(doc).ToString(); + } + + /// <summary> Return a string representation of a doc value, as reuired for Explanations.</summary> + public abstract System.String ToString(int doc); + + /// <summary> Explain the scoring value for the input doc.</summary> + public virtual Explanation Explain(int doc) + { + return new Explanation(FloatVal(doc), ToString(doc)); + } + + /// <summary> Expert: for test purposes only, return the inner array of values, or null if not applicable. + /// <p/> + /// Allows tests to verify that loaded values are: + /// <list type="bullet"> + /// <item>indeed cached/reused.</item> + /// <item>stored in the expected size/type (byte/short/int/float).</item> + /// </list> + /// Note: implementations of DocValues must override this method for + /// these test elements to be tested, Otherwise the test would not fail, just + /// print a warning. + /// </summary> + protected internal virtual object InnerArray + { + get { throw new System.NotSupportedException("this optional method is for test purposes only"); } + } + + // --- some simple statistics on values + private float minVal = System.Single.NaN; + private float maxVal = System.Single.NaN; + private float avgVal = System.Single.NaN; + private bool computed = false; + // compute optional values + private void Compute() + { + if (computed) + { + return ; + } + float sum = 0; + int n = 0; + while (true) + { + float val; + try + { + val = FloatVal(n); + } + catch (System.IndexOutOfRangeException) + { + break; + } + sum += val; + minVal = System.Single.IsNaN(minVal)?val:System.Math.Min(minVal, val); + maxVal = System.Single.IsNaN(maxVal)?val:System.Math.Max(maxVal, val); + ++n; + } + + avgVal = n == 0?System.Single.NaN:sum / n; + computed = true; + } + + /// <summary> Returns the minimum of all values or <c>Float.NaN</c> if this + /// DocValues instance does not contain any value. + /// <p/> + /// This operation is optional + /// <p/> + /// + /// </summary> + /// <returns> the minimum of all values or <c>Float.NaN</c> if this + /// DocValues instance does not contain any value. + /// </returns> + [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1024:UsePropertiesWhereAppropriate")] + public virtual float GetMinValue() + { + Compute(); + return minVal; + } + + /// <summary> Returns the maximum of all values or <c>Float.NaN</c> if this + /// DocValues instance does not contain any value. + /// <p/> + /// This operation is optional + /// <p/> + /// + /// </summary> + /// <returns> the maximum of all values or <c>Float.NaN</c> if this + /// DocValues instance does not contain any value. + /// </returns> + [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1024:UsePropertiesWhereAppropriate")] + public virtual float GetMaxValue() + { + Compute(); + return maxVal; + } + + /// <summary> Returns the average of all values or <c>Float.NaN</c> if this + /// DocValues instance does not contain any value. * + /// <p/> + /// This operation is optional + /// <p/> + /// + /// </summary> + /// <returns> the average of all values or <c>Float.NaN</c> if this + /// DocValues instance does not contain any value + /// </returns> + [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Design", "CA1024:UsePropertiesWhereAppropriate")] + public virtual float GetAverageValue() + { + Compute(); + return avgVal; + } + } +}
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