docs/source/PollingProvider.html

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   8     <pre class="prettyprint lang-js">/*!
   9  * Ext JS Library 3.0.3
  10  * Copyright(c) 2006-2009 Ext JS, LLC
  11  * licensing@extjs.com
  12  * http://www.extjs.com/license
  13  */
  14 <div id="cls-Ext.direct.PollingProvider"></div>/**\r
  15  * @class Ext.direct.PollingProvider\r
  16  * @extends Ext.direct.JsonProvider\r
  17  *\r
  18  * <p>Provides for repetitive polling of the server at distinct {@link #interval intervals}.\r
  19  * The initial request for data originates from the client, and then is responded to by the\r
  20  * server.</p>\r
  21  * \r
  22  * <p>All configurations for the PollingProvider should be generated by the server-side\r
  23  * API portion of the Ext.Direct stack.</p>\r
  24  *\r
  25  * <p>An instance of PollingProvider may be created directly via the new keyword or by simply\r
  26  * specifying <tt>type = 'polling'</tt>.  For example:</p>\r
  27  * <pre><code>\r
  28 var pollA = new Ext.direct.PollingProvider({\r
  29     type:'polling',\r
  30     url: 'php/pollA.php',\r
  31 });\r
  32 Ext.Direct.addProvider(pollA);\r
  33 pollA.disconnect();\r
  34 \r
  35 Ext.Direct.addProvider(\r
  36     {\r
  37         type:'polling',\r
  38         url: 'php/pollB.php',\r
  39         id: 'pollB-provider'\r
  40     }\r
  41 );\r
  42 var pollB = Ext.Direct.getProvider('pollB-provider');\r
  43  * </code></pre>\r
  44  */\r
  45 Ext.direct.PollingProvider = Ext.extend(Ext.direct.JsonProvider, {\r
  46     <div id="cfg-Ext.direct.PollingProvider-priority"></div>/**\r
  47      * @cfg {Number} priority\r
  48      * Priority of the request (defaults to <tt>3</tt>). See {@link Ext.direct.Provider#priority}.\r
  49      */\r
  50     // override default priority\r
  51     priority: 3,\r
  52     \r
  53     <div id="cfg-Ext.direct.PollingProvider-interval"></div>/**\r
  54      * @cfg {Number} interval\r
  55      * How often to poll the server-side in milliseconds (defaults to <tt>3000</tt> - every\r
  56      * 3 seconds).\r
  57      */\r
  58     interval: 3000,\r
  59 \r
  60     <div id="cfg-Ext.direct.PollingProvider-baseParams"></div>/**\r
  61      * @cfg {Object} baseParams An object containing properties which are to be sent as parameters\r
  62      * on every polling request\r
  63      */\r
  64     \r
  65     <div id="cfg-Ext.direct.PollingProvider-url"></div>/**\r
  66      * @cfg {String/Function} url\r
  67      * The url which the PollingProvider should contact with each request. This can also be\r
  68      * an imported Ext.Direct method which will accept the baseParams as its only argument.\r
  69      */\r
  70 \r
  71     // private\r
  72     constructor : function(config){\r
  73         Ext.direct.PollingProvider.superclass.constructor.call(this, config);\r
  74         this.addEvents(\r
  75             <div id="event-Ext.direct.PollingProvider-beforepoll"></div>/**\r
  76              * @event beforepoll\r
  77              * Fired immediately before a poll takes place, an event handler can return false\r
  78              * in order to cancel the poll.\r
  79              * @param {Ext.direct.PollingProvider}\r
  80              */\r
  81             'beforepoll',            \r
  82             <div id="event-Ext.direct.PollingProvider-poll"></div>/**\r
  83              * @event poll\r
  84              * This event has not yet been implemented.\r
  85              * @param {Ext.direct.PollingProvider}\r
  86              */\r
  87             'poll'\r
  88         );\r
  89     },\r
  90 \r
  91     // inherited\r
  92     isConnected: function(){\r
  93         return !!this.pollTask;\r
  94     },\r
  95 \r
  96     <div id="method-Ext.direct.PollingProvider-connect"></div>/**\r
  97      * Connect to the server-side and begin the polling process. To handle each\r
  98      * response subscribe to the data event.\r
  99      */\r
 100     connect: function(){\r
 101         if(this.url && !this.pollTask){\r
 102             this.pollTask = Ext.TaskMgr.start({\r
 103                 run: function(){\r
 104                     if(this.fireEvent('beforepoll', this) !== false){\r
 105                         if(typeof this.url == 'function'){\r
 106                             this.url(this.baseParams);\r
 107                         }else{\r
 108                             Ext.Ajax.request({\r
 109                                 url: this.url,\r
 110                                 callback: this.onData,\r
 111                                 scope: this,\r
 112                                 params: this.baseParams\r
 113                             });\r
 114                         }\r
 115                     }\r
 116                 },\r
 117                 interval: this.interval,\r
 118                 scope: this\r
 119             });\r
 120             this.fireEvent('connect', this);\r
 121         }else if(!this.url){\r
 122             throw 'Error initializing PollingProvider, no url configured.';\r
 123         }\r
 124     },\r
 125 \r
 126     <div id="method-Ext.direct.PollingProvider-disconnect"></div>/**\r
 127      * Disconnect from the server-side and stop the polling process. The disconnect\r
 128      * event will be fired on a successful disconnect.\r
 129      */\r
 130     disconnect: function(){\r
 131         if(this.pollTask){\r
 132             Ext.TaskMgr.stop(this.pollTask);\r
 133             delete this.pollTask;\r
 134             this.fireEvent('disconnect', this);\r
 135         }\r
 136     },\r
 137 \r
 138     // private\r
 139     onData: function(opt, success, xhr){\r
 140         if(success){\r
 141             var events = this.getEvents(xhr);\r
 142             for(var i = 0, len = events.length; i < len; i++){\r
 143                 var e = events[i];\r
 144                 this.fireEvent('data', this, e);\r
 145             }\r
 146         }else{\r
 147             var e = new Ext.Direct.ExceptionEvent({\r
 148                 data: e,\r
 149                 code: Ext.Direct.exceptions.TRANSPORT,\r
 150                 message: 'Unable to connect to the server.',\r
 151                 xhr: xhr\r
 152             });\r
 153             this.fireEvent('data', this, e);\r
 154         }\r
 155     }\r
 156 });\r
 157 \r
 158 Ext.Direct.PROVIDERS['polling'] = Ext.direct.PollingProvider;</pre>
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 160 </html>