| // Copyright 2007 The Closure Library Authors. All Rights Reserved. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS-IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| /** |
| * @fileoverview Defines a class useful for handling functions that must be |
| * invoked after a delay, especially when that delay is frequently restarted. |
| * Examples include delaying before displaying a tooltip, menu hysteresis, |
| * idle timers, etc. |
| * @author brenneman@google.com (Shawn Brenneman) |
| * @see ../demos/timers.html |
| */ |
| |
| |
| goog.provide('goog.Delay'); |
| goog.provide('goog.async.Delay'); |
| |
| goog.require('goog.Disposable'); |
| goog.require('goog.Timer'); |
| |
| |
| |
| /** |
| * A Delay object invokes the associated function after a specified delay. The |
| * interval duration can be specified once in the constructor, or can be defined |
| * each time the delay is started. Calling start on an active delay will reset |
| * the timer. |
| * |
| * @param {function(this:THIS)} listener Function to call when the |
| * delay completes. |
| * @param {number=} opt_interval The default length of the invocation delay (in |
| * milliseconds). |
| * @param {THIS=} opt_handler The object scope to invoke the function in. |
| * @template THIS |
| * @constructor |
| * @extends {goog.Disposable} |
| * @final |
| */ |
| goog.async.Delay = function(listener, opt_interval, opt_handler) { |
| goog.Disposable.call(this); |
| |
| /** |
| * The function that will be invoked after a delay. |
| * @private {function(this:THIS)} |
| */ |
| this.listener_ = listener; |
| |
| /** |
| * The default amount of time to delay before invoking the callback. |
| * @type {number} |
| * @private |
| */ |
| this.interval_ = opt_interval || 0; |
| |
| /** |
| * The object context to invoke the callback in. |
| * @type {Object|undefined} |
| * @private |
| */ |
| this.handler_ = opt_handler; |
| |
| |
| /** |
| * Cached callback function invoked when the delay finishes. |
| * @type {Function} |
| * @private |
| */ |
| this.callback_ = goog.bind(this.doAction_, this); |
| }; |
| goog.inherits(goog.async.Delay, goog.Disposable); |
| |
| |
| |
| /** |
| * A deprecated alias. |
| * @deprecated Use goog.async.Delay instead. |
| * @constructor |
| * @final |
| */ |
| goog.Delay = goog.async.Delay; |
| |
| |
| /** |
| * Identifier of the active delay timeout, or 0 when inactive. |
| * @type {number} |
| * @private |
| */ |
| goog.async.Delay.prototype.id_ = 0; |
| |
| |
| /** |
| * Disposes of the object, cancelling the timeout if it is still outstanding and |
| * removing all object references. |
| * @override |
| * @protected |
| */ |
| goog.async.Delay.prototype.disposeInternal = function() { |
| goog.async.Delay.superClass_.disposeInternal.call(this); |
| this.stop(); |
| delete this.listener_; |
| delete this.handler_; |
| }; |
| |
| |
| /** |
| * Starts the delay timer. The provided listener function will be called after |
| * the specified interval. Calling start on an active timer will reset the |
| * delay interval. |
| * @param {number=} opt_interval If specified, overrides the object's default |
| * interval with this one (in milliseconds). |
| */ |
| goog.async.Delay.prototype.start = function(opt_interval) { |
| this.stop(); |
| this.id_ = goog.Timer.callOnce( |
| this.callback_, |
| goog.isDef(opt_interval) ? opt_interval : this.interval_); |
| }; |
| |
| |
| /** |
| * Stops the delay timer if it is active. No action is taken if the timer is not |
| * in use. |
| */ |
| goog.async.Delay.prototype.stop = function() { |
| if (this.isActive()) { |
| goog.Timer.clear(this.id_); |
| } |
| this.id_ = 0; |
| }; |
| |
| |
| /** |
| * Fires delay's action even if timer has already gone off or has not been |
| * started yet; guarantees action firing. Stops the delay timer. |
| */ |
| goog.async.Delay.prototype.fire = function() { |
| this.stop(); |
| this.doAction_(); |
| }; |
| |
| |
| /** |
| * Fires delay's action only if timer is currently active. Stops the delay |
| * timer. |
| */ |
| goog.async.Delay.prototype.fireIfActive = function() { |
| if (this.isActive()) { |
| this.fire(); |
| } |
| }; |
| |
| |
| /** |
| * @return {boolean} True if the delay is currently active, false otherwise. |
| */ |
| goog.async.Delay.prototype.isActive = function() { |
| return this.id_ != 0; |
| }; |
| |
| |
| /** |
| * Invokes the callback function after the delay successfully completes. |
| * @private |
| */ |
| goog.async.Delay.prototype.doAction_ = function() { |
| this.id_ = 0; |
| if (this.listener_) { |
| this.listener_.call(this.handler_); |
| } |
| }; |