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+/*!
+ * Ext JS Library 3.2.0
+ * Copyright(c) 2006-2010 Ext JS, Inc.
+ * licensing@extjs.com
+ * http://www.extjs.com/license
+ */
+/**
+ * @class Ext.util.DelayedTask
+ * <p> The DelayedTask class provides a convenient way to "buffer" the execution of a method,
+ * performing setTimeout where a new timeout cancels the old timeout. When called, the
+ * task will wait the specified time period before executing. If durng that time period,
+ * the task is called again, the original call will be cancelled. This continues so that
+ * the function is only called a single time for each iteration.</p>
+ * <p>This method is especially useful for things like detecting whether a user has finished
+ * typing in a text field. An example would be performing validation on a keypress. You can
+ * use this class to buffer the keypress events for a certain number of milliseconds, and
+ * perform only if they stop for that amount of time.  Usage:</p><pre><code>
+var task = new Ext.util.DelayedTask(function(){
+    alert(Ext.getDom('myInputField').value.length);
+});
+// Wait 500ms before calling our function. If the user presses another key 
+// during that 500ms, it will be cancelled and we'll wait another 500ms.
+Ext.get('myInputField').on('keypress', function(){
+    task.{@link #delay}(500); 
+});
+ * </code></pre> 
+ * <p>Note that we are using a DelayedTask here to illustrate a point. The configuration
+ * option <tt>buffer</tt> for {@link Ext.util.Observable#addListener addListener/on} will
+ * also setup a delayed task for you to buffer events.</p> 
+ * @constructor The parameters to this constructor serve as defaults and are not required.
+ * @param {Function} fn (optional) The default function to call.
+ * @param {Object} scope The default scope (The <code><b>this</b></code> reference) in which the
+ * function is called. If not specified, <code>this</code> will refer to the browser window.
+ * @param {Array} args (optional) The default Array of arguments.
+ */
+Ext.util.DelayedTask = function(fn, scope, args){
+    var me = this,
+    	id,    	
+    	call = function(){
+    		clearInterval(id);
+	        id = null;
+	        fn.apply(scope, args || []);
+	    };
+	    
+    /**
+     * Cancels any pending timeout and queues a new one
+     * @param {Number} delay The milliseconds to delay
+     * @param {Function} newFn (optional) Overrides function passed to constructor
+     * @param {Object} newScope (optional) Overrides scope passed to constructor. Remember that if no scope
+     * is specified, <code>this</code> will refer to the browser window.
+     * @param {Array} newArgs (optional) Overrides args passed to constructor
+     */
+    me.delay = function(delay, newFn, newScope, newArgs){
+        me.cancel();
+        fn = newFn || fn;
+        scope = newScope || scope;
+        args = newArgs || args;
+        id = setInterval(call, delay);
+    };
+
+    /**
+     * Cancel the last queued timeout
+     */
+    me.cancel = function(){
+        if(id){
+            clearInterval(id);
+            id = null;
+        }
+    };
+};
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