File: datasource/js/datasource-polling.js

            /**
             * Extends DataSource with polling functionality.
             *
             * @module datasource
             * @submodule datasource-polling
             */
            
            /**
             * Adds polling to the DataSource Utility.
             * @class Pollable
             * @extends DataSource.Local
             */
            function Pollable() {
                this._intervals = {};
            }
            
            Pollable.prototype = {
            
                /**
                * @property _intervals
                * @description Hash of polling interval IDs that have been enabled,
                * stored here to be able to clear all intervals.
                * @private
                */
                _intervals: null,
            
                /**
                 * Sets up a polling mechanism to send requests at set intervals and
                 * forward responses to given callback.
                 *
                 * @method setInterval
                 * @param msec {Number} Length of interval in milliseconds.
                 * @param [request] {Object} An object literal with the following properties:
                 *     <dl>
                 *     <dt><code>request</code></dt>
                 *     <dd>The request to send to the live data source, if any.</dd>
                 *     <dt><code>callback</code></dt>
                 *     <dd>An object literal with the following properties:
                 *         <dl>
                 *         <dt><code>success</code></dt>
                 *         <dd>The function to call when the data is ready.</dd>
                 *         <dt><code>failure</code></dt>
                 *         <dd>The function to call upon a response failure condition.</dd>
                 *         <dt><code>argument</code></dt>
                 *         <dd>Arbitrary data payload that will be passed back to the success and failure handlers.</dd>
                 *         </dl>
                 *     </dd>
                 *     <dt><code>cfg</code></dt>
                 *     <dd>Configuration object, if any.</dd>
                 *     </dl>
                 * @return {Number} Interval ID.
                 */
                setInterval: function(msec, request) {
                    var x = Y.later(msec, this, this.sendRequest, [ request ], true);
                    this._intervals[x.id] = x;
                    // First call happens immediately, but async
                    Y.later(0, this, this.sendRequest, [request]);
                    return x.id;
                },
            
                /**
                 * Disables polling mechanism associated with the given interval ID.
                 *
                 * @method clearInterval
                 * @param id {Number} Interval ID.
                 */
                clearInterval: function(id, key) {
                    // In case of being called by clearAllIntervals()
                    id = key || id;
                    if(this._intervals[id]) {
                        // Clear the interval
                        this._intervals[id].cancel();
                        // Clear from tracker
                        delete this._intervals[id];
                    }
                },
            
                /**
                 * Clears all intervals.
                 *
                 * @method clearAllIntervals
                 */
                clearAllIntervals: function() {
                    Y.each(this._intervals, this.clearInterval, this);
                }
            };
            
            Y.augment(Y.DataSource.Local, Pollable);