text: // Copyright 2006 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 Definition of the MenuBase class.
   *
  *
   */
  
  goog.provide('goog.ui.MenuBase');
  
  goog.require('goog.events.EventHandler');
  goog.require('goog.events.EventType');
  goog.require('goog.events.KeyHandler');
  goog.require('goog.events.KeyHandler.EventType');
  goog.require('goog.ui.Popup');
  
  /**
   * The MenuBase class provides an abstract base class for different
   * implementations of menu controls.
   *
   * @param {Element=} opt_element A DOM element for the popup.
   * @deprecated Use goog.ui.Menu.
   * @constructor
   * @extends {goog.ui.Popup}
   */
  goog.ui.MenuBase = function(opt_element) {
    goog.ui.Popup.call(this, opt_element);
  
    /**
     * Event handler for simplifiying adding/removing listeners.
     * @type {goog.events.EventHandler}
     * @private
     */
    this.eventHandler_ = new goog.events.EventHandler(this);
  
    /**
     * KeyHandler to cope with the vagaries of cross-browser key events.
     * @type {goog.events.KeyHandler}
     * @private
     */
    this.keyHandler_ = new goog.events.KeyHandler(this.getElement());
  };
  goog.inherits(goog.ui.MenuBase, goog.ui.Popup);
  
  
  /**
   * Events fired by the Menu
   */
  goog.ui.MenuBase.Events = {};
  
  
  /**
   * Event fired by the Menu when an item is "clicked".
   */
  goog.ui.MenuBase.Events.ITEM_ACTION = 'itemaction';
  
  
  /** @inheritDoc */
  goog.ui.MenuBase.prototype.disposeInternal = function() {
    goog.ui.MenuBase.superClass_.disposeInternal.call(this);
    this.eventHandler_.dispose();
    this.keyHandler_.dispose();
  };
  
  
  /**
   * Called after the menu is shown. Derived classes can override to hook this
   * event but should make sure to call the parent class method.
   *
   * @protected
   * @suppress {underscore}
   * @override
   */
  goog.ui.MenuBase.prototype.onShow_ = function() {
    goog.ui.MenuBase.superClass_.onShow_.call(this);
  
    // register common event handlers for derived classes
    var el = this.getElement();
    this.eventHandler_.listen(
        el, goog.events.EventType.MOUSEOVER, this.onMouseOver);
    this.eventHandler_.listen(
        el, goog.events.EventType.MOUSEOUT, this.onMouseOut);
    this.eventHandler_.listen(
        el, goog.events.EventType.MOUSEDOWN, this.onMouseDown);
    this.eventHandler_.listen(
        el, goog.events.EventType.MOUSEUP, this.onMouseUp);
  
    this.eventHandler_.listen(
        this.keyHandler_,
        goog.events.KeyHandler.EventType.KEY,
        this.onKeyDown);
  };
  
  /**
   * Called after the menu is hidden. Derived classes can override to hook this
   * event but should make sure to call the parent class method.
   * @param {Object=} opt_target Target of the event causing the hide.
   * @protected
   * @suppress {underscore}
   * @override
   */
  goog.ui.MenuBase.prototype.onHide_ = function(opt_target) {
    goog.ui.MenuBase.superClass_.onHide_.call(this, opt_target);
  
    // remove listeners when hidden
    this.eventHandler_.removeAll();
  };
  
  
  /**
   * Returns the selected item
   *
   * @return {Object} The item selected or null if no item is selected.
   */
  goog.ui.MenuBase.prototype.getSelectedItem = function() {
    return null;
  };
  
  
  /**
   * Sets the selected item
   *
   * @param {Object} item The item to select. The type of this item is specific
   * to the menu class.
   */
  goog.ui.MenuBase.prototype.setSelectedItem = function(item) {
  };
  
  
  /**
   * Mouse over handler for the menu. Derived classes should override.
   *
   * @param {goog.events.Event} e The event object.
   * @protected
   */
  goog.ui.MenuBase.prototype.onMouseOver = function(e) {
  };
  
  
  /**
   * Mouse out handler for the menu. Derived classes should override.
   *
   * @param {goog.events.Event} e The event object.
   * @protected
   */
  goog.ui.MenuBase.prototype.onMouseOut = function(e) {
  };
  
  
  /**
   * Mouse down handler for the menu. Derived classes should override.
   *
   * @param {goog.events.Event} e The event object.
   * @protected
   */
  goog.ui.MenuBase.prototype.onMouseDown = function(e) {
  };
  
  
  /**
   * Mouse up handler for the menu. Derived classes should override.
   *
   * @param {goog.events.Event} e The event object.
   * @protected
   */
  goog.ui.MenuBase.prototype.onMouseUp = function(e) {
  };
  
  
  /**
   * Key down handler for the menu. Derived classes should override.
   *
   * @param {goog.events.KeyEvent} e The event object.
   * @protected
   */
  goog.ui.MenuBase.prototype.onKeyDown = function(e) {
  };
  