dojo_app/js/library/dojo/store/Memory.js

define(["../_base/declare", "./util/QueryResults", "./util/SimpleQueryEngine" /*=====, "./api/Store" =====*/],
function(declare, QueryResults, SimpleQueryEngine /*=====, Store =====*/){

// module:
//		dojo/store/Memory

// No base class, but for purposes of documentation, the base class is dojo/store/api/Store
var base = null;
/*===== base = Store; =====*/

return declare("dojo.store.Memory", base, {
	// summary:
	//		This is a basic in-memory object store. It implements dojo/store/api/Store.
	constructor: function(options){
		// summary:
		//		Creates a memory object store.
		// options: dojo/store/Memory
		//		This provides any configuration information that will be mixed into the store.
		//		This should generally include the data property to provide the starting set of data.
		for(var i in options){
			this[i] = options[i];
		}
		this.setData(this.data || []);
	},
	// data: Array
	//		The array of all the objects in the memory store
	data:null,

	// idProperty: String
	//		Indicates the property to use as the identity property. The values of this
	//		property should be unique.
	idProperty: "id",

	// index: Object
	//		An index of data indices into the data array by id
	index:null,

	// queryEngine: Function
	//		Defines the query engine to use for querying the data store
	queryEngine: SimpleQueryEngine,
	get: function(id){
		// summary:
		//		Retrieves an object by its identity
		// id: Number
		//		The identity to use to lookup the object
		// returns: Object
		//		The object in the store that matches the given id.
		return this.data[this.index[id]];
	},
	getIdentity: function(object){
		// summary:
		//		Returns an object's identity
		// object: Object
		//		The object to get the identity from
		// returns: Number
		return object[this.idProperty];
	},
	put: function(object, options){
		// summary:
		//		Stores an object
		// object: Object
		//		The object to store.
		// options: dojo/store/api/Store.PutDirectives?
		//		Additional metadata for storing the data.  Includes an "id"
		//		property if a specific id is to be used.
		// returns: Number
		var data = this.data;
		var index = this.index;
		var idProperty = this.idProperty;
		var id = object[idProperty] = (options && "id" in options) ?
			options.id : idProperty in object ? object[idProperty] : Math.random();
		var defaultDestination = data.length;
		var newIndex;
		var previousIndex;
		var eventType = id in index ? "update" : "add";

		if(eventType === "update"){
			if(options && options.overwrite === false){
				throw new Error("Object already exists");
			}
			else{
				previousIndex = index[id];
				defaultDestination = previousIndex;
			}
		}

		if(options && "before" in options){
			if(options.before == null){
				newIndex = data.length;
				if(eventType === "update"){
					--newIndex;
				}
			}
			else{
				newIndex = index[this.getIdentity(options.before)];
				// Account for the removed item
				if(previousIndex < newIndex){
					--newIndex;
				}
			}
		}
		else{
			newIndex = defaultDestination;
		}

		if(newIndex === previousIndex){
			data[newIndex] = object;
		}
		else{
			if(previousIndex !== undefined){
				data.splice(previousIndex, 1);
			}
			data.splice(newIndex, 0, object);
			this._rebuildIndex(previousIndex === undefined ? newIndex : Math.min(previousIndex, newIndex));
		}

		return id;
	},
	add: function(object, options){
		// summary:
		//		Creates an object, throws an error if the object already exists
		// object: Object
		//		The object to store.
		// options: dojo/store/api/Store.PutDirectives?
		//		Additional metadata for storing the data.  Includes an "id"
		//		property if a specific id is to be used.
		// returns: Number
		(options = options || {}).overwrite = false;
		// call put with overwrite being false
		return this.put(object, options);
	},
	remove: function(id){
		// summary:
		//		Deletes an object by its identity
		// id: Number
		//		The identity to use to delete the object
		// returns: Boolean
		//		Returns true if an object was removed, falsy (undefined) if no object matched the id
		var index = this.index;
		var data = this.data;
		if(id in index){
			data.splice(index[id], 1);
			this.index = {};
			this._rebuildIndex();
			return true;
		}
	},
	query: function(query, options){
		// summary:
		//		Queries the store for objects.
		// query: Object
		//		The query to use for retrieving objects from the store.
		// options: dojo/store/api/Store.QueryOptions?
		//		The optional arguments to apply to the resultset.
		// returns: dojo/store/api/Store.QueryResults
		//		The results of the query, extended with iterative methods.
		//
		// example:
		//		Given the following store:
		//
		// 	|	var store = new Memory({
		// 	|		data: [
		// 	|			{id: 1, name: "one", prime: false },
		//	|			{id: 2, name: "two", even: true, prime: true},
		//	|			{id: 3, name: "three", prime: true},
		//	|			{id: 4, name: "four", even: true, prime: false},
		//	|			{id: 5, name: "five", prime: true}
		//	|		]
		//	|	});
		//
		//	...find all items where "prime" is true:
		//
		//	|	var results = store.query({ prime: true });
		//
		//	...or find all items where "even" is true:
		//
		//	|	var results = store.query({ even: true });
		return QueryResults(this.queryEngine(query, options)(this.data));
	},
	setData: function(data){
		// summary:
		//		Sets the given data as the source for this store, and indexes it
		// data: Object[]
		//		An array of objects to use as the source of data.
		if(data.items){
			// just for convenience with the data format IFRS expects
			this.idProperty = data.identifier || this.idProperty;
			data = this.data = data.items;
		}else{
			this.data = data;
		}
		this.index = {};
		this._rebuildIndex();
	},
	_rebuildIndex: function(startIndex){
		var data = this.data;
		var dataLength = data.length;
		var i;

		startIndex = startIndex || 0;

		for(i = startIndex; i < dataLength; i++){
			this.index[data[i][this.idProperty]] = i;
		}
	}
});

});