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// Copyright 2005 The Closure Library Authors. All Rights Reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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//      http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS-IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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/**
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 * @fileoverview A base class for event objects.
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 *
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 */
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goog.provide('goog.events.Event');
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goog.provide('goog.events.EventLike');
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/**
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 * goog.events.Event no longer depends on goog.Disposable. Keep requiring
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 * goog.Disposable here to not break projects which assume this dependency.
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 * @suppress {extraRequire}
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 */
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goog.require('goog.Disposable');
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goog.require('goog.events.EventId');
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/**
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 * A typedef for event like objects that are dispatchable via the
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 * goog.events.dispatchEvent function. strings are treated as the type for a
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 * goog.events.Event. Objects are treated as an extension of a new
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 * goog.events.Event with the type property of the object being used as the type
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 * of the Event.
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 * @typedef {string|Object|goog.events.Event|goog.events.EventId}
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 */
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goog.events.EventLike;
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/**
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 * A base class for event objects, so that they can support preventDefault and
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 * stopPropagation.
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 *
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 * @suppress {underscore} Several properties on this class are technically
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 *     public, but referencing these properties outside this package is strongly
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 *     discouraged.
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 *
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 * @param {string|!goog.events.EventId} type Event Type.
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 * @param {Object=} opt_target Reference to the object that is the target of
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 *     this event. It has to implement the {@code EventTarget} interface
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 *     declared at {@link http://developer.mozilla.org/en/DOM/EventTarget}.
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 * @constructor
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 */
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goog.events.Event = function(type, opt_target) {
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  /**
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   * Event type.
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   * @type {string}
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   */
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  this.type = type instanceof goog.events.EventId ? String(type) : type;
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  /**
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   * TODO(tbreisacher): The type should probably be
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   * EventTarget|goog.events.EventTarget.
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   *
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   * Target of the event.
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   * @type {Object|undefined}
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   */
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  this.target = opt_target;
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  /**
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   * Object that had the listener attached.
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   * @type {Object|undefined}
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   */
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  this.currentTarget = this.target;
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  /**
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   * Whether to cancel the event in internal capture/bubble processing for IE.
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   * @type {boolean}
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   * @public
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   */
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  this.propagationStopped_ = false;
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  /**
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   * Whether the default action has been prevented.
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   * This is a property to match the W3C specification at
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   * {@link http://www.w3.org/TR/DOM-Level-3-Events/
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   * #events-event-type-defaultPrevented}.
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   * Must be treated as read-only outside the class.
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   * @type {boolean}
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   */
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  this.defaultPrevented = false;
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  /**
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   * Return value for in internal capture/bubble processing for IE.
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   * @type {boolean}
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   * @public
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   */
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  this.returnValue_ = true;
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};
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/**
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 * Stops event propagation.
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 */
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goog.events.Event.prototype.stopPropagation = function() {
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  this.propagationStopped_ = true;
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};
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/**
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 * Prevents the default action, for example a link redirecting to a url.
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 */
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goog.events.Event.prototype.preventDefault = function() {
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  this.defaultPrevented = true;
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  this.returnValue_ = false;
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};
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/**
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 * Stops the propagation of the event. It is equivalent to
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 * {@code e.stopPropagation()}, but can be used as the callback argument of
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 * {@link goog.events.listen} without declaring another function.
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 * @param {!goog.events.Event} e An event.
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 */
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goog.events.Event.stopPropagation = function(e) {
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  e.stopPropagation();
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};
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/**
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 * Prevents the default action. It is equivalent to
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 * {@code e.preventDefault()}, but can be used as the callback argument of
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 * {@link goog.events.listen} without declaring another function.
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 * @param {!goog.events.Event} e An event.
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 */
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goog.events.Event.preventDefault = function(e) {
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  e.preventDefault();
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};
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