/**
+ * Extends DataSource with caching functionality.
+ *
+ * @module datasource
+ * @submodule datasource-cache
+ */
+
+/**
+ * Adds cacheability to the DataSource Utility.
+ * @class DataSourceCache
+ * @extends Cache
+ */
+var DataSourceCache = function() {
+ DataSourceCache.superclass.constructor.apply(this, arguments);
+};
+
+Y.mix(DataSourceCache, {
+ /**
+ * The namespace for the plugin. This will be the property on the host which
+ * references the plugin instance.
+ *
+ * @property NS
+ * @type String
+ * @static
+ * @final
+ * @value "cache"
+ */
+ NS: "cache",
+
+ /**
+ * Class name.
+ *
+ * @property NAME
+ * @type String
+ * @static
+ * @final
+ * @value "dataSourceCache"
+ */
+ NAME: "dataSourceCache",
+
+ /////////////////////////////////////////////////////////////////////////////
+ //
+ // DataSourceCache Attributes
+ //
+ /////////////////////////////////////////////////////////////////////////////
+
+ ATTRS: {
+
+ }
+});
+
+Y.extend(DataSourceCache, Y.Cache, {
+ /**
+ * Internal init() handler.
+ *
+ * @method initializer
+ * @param config {Object} Config object.
+ * @private
+ */
+ initializer: function(config) {
+ this.doBefore("_defRequestFn", this._beforeDefRequestFn);
+ this.doBefore("_defResponseFn", this._beforeDefResponseFn);
+ },
+
+ /**
+ * First look for cached response, then send request to live data.
+ *
+ * @method _beforeDefRequestFn
+ * @param e {Event.Facade} Event Facade with the following properties:
+ * <dl>
+ * <dt>tId (Number)</dt> <dd>Unique transaction ID.</dd>
+ * <dt>request (Object)</dt> <dd>The request.</dd>
+ * <dt>callback (Object)</dt> <dd>The callback object.</dd>
+ * <dt>cfg (Object)</dt> <dd>Configuration object.</dd>
+ * </dl>
+ * @protected
+ */
+ _beforeDefRequestFn: function(e) {
+ // Is response already in the Cache?
+ var entry = (this.retrieve(e.request)) || null;
+ if(entry && entry.response) {
+ this.get("host").fire("response", Y.mix({response: entry.response}, e));
+ return new Y.Do.Halt("DataSourceCache plugin halted _defRequestFn");
+ }
+ },
+
+ /**
+ * Adds data to cache before returning data.
+ *
+ * @method _beforeDefResponseFn
+ * @param e {Event.Facade} Event Facade with the following properties:
+ * <dl>
+ * <dt>tId (Number)</dt> <dd>Unique transaction ID.</dd>
+ * <dt>request (Object)</dt> <dd>The request.</dd>
+ * <dt>callback (Object)</dt> <dd>The callback object with the following properties:
+ * <dl>
+ * <dt>success (Function)</dt> <dd>Success handler.</dd>
+ * <dt>failure (Function)</dt> <dd>Failure handler.</dd>
+ * </dl>
+ * </dd>
+ * <dt>data (Object)</dt> <dd>Raw data.</dd>
+ * <dt>response (Object)</dt> <dd>Normalized response object with the following properties:
+ * <dl>
+ * <dt>cached (Object)</dt> <dd>True when response is cached.</dd>
+ * <dt>results (Object)</dt> <dd>Parsed results.</dd>
+ * <dt>meta (Object)</dt> <dd>Parsed meta data.</dd>
+ * <dt>error (Object)</dt> <dd>Error object.</dd>
+ * </dl>
+ * </dd>
+ * <dt>cfg (Object)</dt> <dd>Configuration object.</dd>
+ * </dl>
+ * @protected
+ */
+ _beforeDefResponseFn: function(e) {
+ // Add to Cache before returning
+ if(e.response && !e.response.cached) {
+ e.response.cached = true;
+ this.add(e.request, e.response, (e.callback && e.callback.argument));
+ }
+ }
+});
+
+Y.namespace('Plugin').DataSourceCache = DataSourceCache;
+