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/*****************************************************************************
* Open MCT, Copyright (c) 2014-2021, United States Government
* as represented by the Administrator of the National Aeronautics and Space
* Administration. All rights reserved.
*
* Open MCT is licensed 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.
*
* Open MCT includes source code licensed under additional open source
* licenses. See the Open Source Licenses file (LICENSES.md) included with
* this source code distribution or the Licensing information page available
* at runtime from the About dialog for additional information.
*****************************************************************************/
import _ from 'lodash';
import utils from './object-utils.js';
import EventEmitter from 'EventEmitter';
const ANY_OBJECT_EVENT = 'mutation';
/**
* Wraps a domain object to keep its model synchronized with other instances of the same object.
*
* Creating a MutableDomainObject will automatically register listeners to keep its model in sync. As such, developers
* should be careful to destroy MutableDomainObject in order to avoid memory leaks.
*
* All Open MCT API functions that provide objects will provide MutableDomainObjects where possible, except
* `openmct.objects.get()`, and will manage that object's lifecycle for you. Calling `openmct.objects.getMutable()`
* will result in the creation of a new MutableDomainObject and you will be responsible for destroying it
* (via openmct.objects.destroy) when you're done with it.
*
* @typedef MutableDomainObject
* @memberof module:openmct
*/
class MutableDomainObject {
constructor(eventEmitter) {
Object.defineProperties(this, {
_globalEventEmitter: {
value: eventEmitter,
// Property should not be serialized
enumerable: false
},
_instanceEventEmitter: {
value: new EventEmitter(),
// Property should not be serialized
enumerable: false
},
_observers: {
value: [],
// Property should not be serialized
enumerable: false
},
isMutable: {
value: true,
// Property should not be serialized
enumerable: false
}
});
}
$observe(path, callback) {
let fullPath = qualifiedEventName(this, path);
let eventOff =
this._globalEventEmitter.off.bind(this._globalEventEmitter, fullPath, callback);
this._globalEventEmitter.on(fullPath, callback);
this._observers.push(eventOff);
return eventOff;
}
$set(path, value) {
_.set(this, path, value);
if (path !== 'persisted' && path !== 'modified') {
_.set(this, 'modified', Date.now());
}
//Emit secret synchronization event first, so that all objects are in sync before subsequent events fired.
this._globalEventEmitter.emit(qualifiedEventName(this, '$_synchronize_model'), this);
//Emit a general "any object" event
this._globalEventEmitter.emit(ANY_OBJECT_EVENT, this);
//Emit wildcard event, with path so that callback knows what changed
this._globalEventEmitter.emit(qualifiedEventName(this, '*'), this, path, value);
//Emit events specific to properties affected
let parentPropertiesList = path.split('.');
for (let index = parentPropertiesList.length; index > 0; index--) {
let parentPropertyPath = parentPropertiesList.slice(0, index).join('.');
this._globalEventEmitter.emit(qualifiedEventName(this, parentPropertyPath), _.get(this, parentPropertyPath));
}
//TODO: Emit events for listeners of child properties when parent changes.
// Do it at observer time - also register observers for parent attribute path.
}
$refresh(model) {
//TODO: Currently we are updating the entire object.
// In the future we could update a specific property of the object using the 'path' parameter.
this._globalEventEmitter.emit(qualifiedEventName(this, '$_synchronize_model'), model);
//Emit wildcard event, with path so that callback knows what changed
this._globalEventEmitter.emit(qualifiedEventName(this, '*'), this);
}
$on(event, callback) {
this._instanceEventEmitter.on(event, callback);
return () => this._instanceEventEmitter.off(event, callback);
}
$destroy() {
while (this._observers.length > 0) {
const observer = this._observers.pop();
observer();
}
this._instanceEventEmitter.emit('$_destroy');
}
static createMutable(object, mutationTopic) {
let mutable = Object.create(new MutableDomainObject(mutationTopic));
Object.assign(mutable, object);
mutable.$observe('$_synchronize_model', (updatedObject) => {
let clone = JSON.parse(JSON.stringify(updatedObject));
utils.refresh(mutable, clone);
});
return mutable;
}
static mutateObject(object, path, value) {
_.set(object, path, value);
_.set(object, 'modified', Date.now());
}
}
function qualifiedEventName(object, eventName) {
let keystring = utils.makeKeyString(object.identifier);
return [keystring, eventName].join(':');
}
export default MutableDomainObject;
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