Event.js

/*
* Event
* Visit http://createjs.com/ for window.documentation, updates and examples.
*
* Copyright (c) 2010 gskinner.com, inc.
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated window.documentation
* files (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use,
* copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following
* conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/

/**
 * A collection of Classes that are shared across all the CreateJS libraries.  The classes are included in the minified
 * files of each library and are available on the createsjs namespace directly.
 *
 * <h4>Example</h4>
 *
 *      myObject.addEventListener("change", createjs.proxy(myMethod, scope));
 *
 * @module CreateJS
 * @main CreateJS
 */

// namespace:
this.createjs = this.createjs||{};

(function() {
	"use strict";

// constructor:
	/**
	 * Contains properties and methods shared by all events for use with
	 * {{#crossLink "EventDispatcher"}}{{/crossLink}}.
	 * 
	 * Note that Event objects are often reused, so you should never
	 * rely on an event object's state outside of the call stack it was received in.
	 * @class Event
	 * @param {String} type The event type.
	 * @param {Boolean} bubbles Indicates whether the event will bubble through the display list.
	 * @param {Boolean} cancelable Indicates whether the default behaviour of this event can be cancelled.
	 * @constructor
	 **/
	function Event(type, bubbles, cancelable) {
		
	
	// public properties:
		/**
		 * The type of event.
		 * @property type
		 * @type String
		 **/
		this.type = type;
	
		/**
		 * The object that generated an event.
		 * @property target
		 * @type Object
		 * @default null
		 * @readonly
		*/
		this.target = null;
	
		/**
		 * The current target that a bubbling event is being dispatched from. For non-bubbling events, this will
		 * always be the same as target. For example, if childObj.parent = parentObj, and a bubbling event
		 * is generated from childObj, then a listener on parentObj would receive the event with
		 * target=childObj (the original target) and currentTarget=parentObj (where the listener was added).
		 * @property currentTarget
		 * @type Object
		 * @default null
		 * @readonly
		*/
		this.currentTarget = null;
	
		/**
		 * For bubbling events, this indicates the current event phase:<OL>
		 * 	<LI> capture phase: starting from the top parent to the target</LI>
		 * 	<LI> at target phase: currently being dispatched from the target</LI>
		 * 	<LI> bubbling phase: from the target to the top parent</LI>
		 * </OL>
		 * @property eventPhase
		 * @type Number
		 * @default 0
		 * @readonly
		*/
		this.eventPhase = 0;
	
		/**
		 * Indicates whether the event will bubble through the display list.
		 * @property bubbles
		 * @type Boolean
		 * @default false
		 * @readonly
		*/
		this.bubbles = !!bubbles;
	
		/**
		 * Indicates whether the default behaviour of this event can be cancelled via
		 * {{#crossLink "Event/preventDefault"}}{{/crossLink}}. This is set via the Event constructor.
		 * @property cancelable
		 * @type Boolean
		 * @default false
		 * @readonly
		*/
		this.cancelable = !!cancelable;
	
		/**
		 * The epoch time at which this event was created.
		 * @property timeStamp
		 * @type Number
		 * @default 0
		 * @readonly
		*/
		this.timeStamp = (new Date()).getTime();
	
		/**
		 * Indicates if {{#crossLink "Event/preventDefault"}}{{/crossLink}} has been called
		 * on this event.
		 * @property defaultPrevented
		 * @type Boolean
		 * @default false
		 * @readonly
		*/
		this.defaultPrevented = false;
	
		/**
		 * Indicates if {{#crossLink "Event/stopPropagation"}}{{/crossLink}} or
		 * {{#crossLink "Event/stopImmediatePropagation"}}{{/crossLink}} has been called on this event.
		 * @property propagationStopped
		 * @type Boolean
		 * @default false
		 * @readonly
		*/
		this.propagationStopped = false;
	
		/**
		 * Indicates if {{#crossLink "Event/stopImmediatePropagation"}}{{/crossLink}} has been called
		 * on this event.
		 * @property immediatePropagationStopped
		 * @type Boolean
		 * @default false
		 * @readonly
		*/
		this.immediatePropagationStopped = false;
		
		/**
		 * Indicates if {{#crossLink "Event/remove"}}{{/crossLink}} has been called on this event.
		 * @property removed
		 * @type Boolean
		 * @default false
		 * @readonly
		*/
		this.removed = false;
	}
	var p = Event.prototype;

	/**
	 * <strong>REMOVED</strong>. Removed in favor of using `MySuperClass_constructor`.
	 * See {{#crossLink "Utility Methods/extend"}}{{/crossLink}} and {{#crossLink "Utility Methods/promote"}}{{/crossLink}}
	 * for details.
	 *
	 * There is an inheritance tutorial distributed with EaselJS in /tutorials/Inheritance.
	 *
	 * @method initialize
	 * @protected
	 * @deprecated
	 */
	// p.initialize = function() {}; // searchable for devs wondering where it is.

// public methods:
	/**
	 * Sets {{#crossLink "Event/defaultPrevented"}}{{/crossLink}} to true if the event is cancelable.
	 * Mirrors the DOM level 2 event standard. In general, cancelable events that have `preventDefault()` called will
	 * cancel the default behaviour associated with the event.
	 * @method preventDefault
	 **/
	p.preventDefault = function() {
		this.defaultPrevented = this.cancelable&&true;
	};

	/**
	 * Sets {{#crossLink "Event/propagationStopped"}}{{/crossLink}} to true.
	 * Mirrors the DOM event standard.
	 * @method stopPropagation
	 **/
	p.stopPropagation = function() {
		this.propagationStopped = true;
	};

	/**
	 * Sets {{#crossLink "Event/propagationStopped"}}{{/crossLink}} and
	 * {{#crossLink "Event/immediatePropagationStopped"}}{{/crossLink}} to true.
	 * Mirrors the DOM event standard.
	 * @method stopImmediatePropagation
	 **/
	p.stopImmediatePropagation = function() {
		this.immediatePropagationStopped = this.propagationStopped = true;
	};
	
	/**
	 * Causes the active listener to be removed via removeEventListener();
	 * 
	 * 		myBtn.addEventListener("click", function(evt) {
	 * 			// do stuff...
	 * 			evt.remove(); // removes this listener.
	 * 		});
	 * 
	 * @method remove
	 **/
	p.remove = function() {
		this.removed = true;
	};
	
	/**
	 * Returns a clone of the Event instance.
	 * @method clone
	 * @return {Event} a clone of the Event instance.
	 **/
	p.clone = function() {
		return new Event(this.type, this.bubbles, this.cancelable);
	};
	
	/**
	 * Provides a chainable shortcut method for setting a number of properties on the instance.
	 *
	 * @method set
	 * @param {Object} props A generic object containing properties to copy to the instance.
	 * @return {Event} Returns the instance the method is called on (useful for chaining calls.)
	 * @chainable
	*/
	p.set = function(props) {
		for (var n in props) { this[n] = props[n]; }
		return this;
	};

	/**
	 * Returns a string representation of this object.
	 * @method toString
	 * @return {String} a string representation of the instance.
	 **/
	p.toString = function() {
		return "[Event (type="+this.type+")]";
	};

	createjs.Event = Event;
}());