    /**
     * @class Ext.grid.plugin.DragDrop
     * <p>This plugin provides drag and/or drop functionality for a GridView.</p>
     * <p>It creates a specialized instance of {@link Ext.dd.DragZone DragZone} which knows how to drag out of a {@link Ext.grid.View GridView}
     * and loads the data object which is passed to a cooperating {@link Ext.dd.DragZone DragZone}'s methods with the following properties:<ul>
     * <li>copy : Boolean
     *  <div class="sub-desc">The value of the GridView's <code>copy</code> property, or <code>true</code> if the GridView was configured
     *  with <code>allowCopy: true</code> <u>and</u> the control key was pressed when the drag operation was begun.</div></li>
     * <li>view : GridView
     *  <div class="sub-desc">The source GridView from which the drag originated.</div></li>
     * <li>ddel : HtmlElement
     *  <div class="sub-desc">The drag proxy element which moves with the mouse</div></li>
     * <li>item : HtmlElement
     *  <div class="sub-desc">The GridView node upon which the mousedown event was registered.</div></li>
     * <li>records : Array
     *  <div class="sub-desc">An Array of {@link Ext.data.Model Model}s representing the selected data being dragged from the source GridView.</div></li>
     * </ul></p>
     * <p>It also creates a specialized instance of {@link Ext.dd.DropZone} which cooperates with other DropZones which are members of the same
     * ddGroup which processes such data objects.</p>
     * <p>Adding this plugin to a view means that two new events may be fired from the client GridView, <code>{@link #event-beforedrop beforedrop}</code> and
     * <code>{@link #event-drop drop}</code></p>
     */
    Ext.define('Ext.grid.plugin.DragDrop', {
        extend: 'Ext.AbstractPlugin',
        alias: 'plugin.gridviewdragdrop',

        uses: [
            'Ext.view.DragZone',
            'Ext.grid.ViewDropZone'
        ],

        /**
         * @event beforedrop
         * <p><b>This event is fired through the GridView. Add listeners to the GridView object</b></p>
         * <p>Fired when a drop gesture has been triggered by a mouseup event in a valid drop position in the GridView.
         * @param {HtmlElement} node The GridView node <b>if any</b> over which the mouse was positioned.</p>
         * <p>Returning <code>false</code> to this event signals that the drop gesture was invalid, and if the drag proxy
         * will animate back to the point from which the drag began.</p>
         * <p>Returning <code>0</code> To this event signals that the data transfer operation should not take place, but
         * that the gesture was valid, and that the repair operation should not take place.</p>
         * <p>Any other return value continues with the data transfer operation.</p>
         * @param {Object} data The data object gathered at mousedown time by the cooperating {@link Ext.dd.DragZone DragZone}'s
         * {@link Ext.dd.DragZone#getDragData getDragData} method it contains the following properties:<ul>
         * <li>copy : Boolean
         *  <div class="sub-desc">The value of the GridView's <code>copy</code> property, or <code>true</code> if the GridView was configured
         *  with <code>allowCopy: true</code> and the control key was pressed when the drag operation was begun</div></li>
         * <li>view : GridView
         *  <div class="sub-desc">The source GridView from which the drag originated.</div></li>
         * <li>ddel : HtmlElement
         *  <div class="sub-desc">The drag proxy element which moves with the mouse</div></li>
         * <li>item : HtmlElement
         *  <div class="sub-desc">The GridView node upon which the mousedown event was registered.</div></li>
         * <li>records : Array
         *  <div class="sub-desc">An Array of {@link Ext.data.Model Model}s representing the selected data being dragged from the source GridView.</div></li>
         * </ul>
         * @param {Ext.data.Model} overModel The Model over which the drop gesture took place.
         * @param {String} dropPosition <code>"before"</code> or <code>"after"</code> depending on whether the mouse is above or below the midline of the node.
         * @param {Function} dropFunction <p>A function to call to complete the data transfer operation and either move or copy Model instances from the source
         * View's Store to the destination View's Store.</p>
         * <p>This is useful when you want to perform some kind of asynchronous processing before confirming
         * the drop, such as an {@link Ext.window.MessageBox#confirm confirm} call, or an Ajax request.</p>
         * <p>Return <code>0</code> from this event handler, and call the <code>dropFunction</code> at any time to perform the data transfer.</p>
         */

        /**
         * @event drop
         * <b>This event is fired through the GridView. Add listeners to the GridView object</b>
         * Fired when a drop operation has been completed and the data has been moved or copied.
         * @param {HtmlElement} node The GridView node <b>if any</b> over which the mouse was positioned.
         * @param {Object} data The data object gathered at mousedown time by the cooperating {@link Ext.dd.DragZone DragZone}'s
         * {@link Ext.dd.DragZone#getDragData getDragData} method it contains the following properties:<ul>
         * <li>copy : Boolean
         *  <div class="sub-desc">The value of the GridView's <code>copy</code> property, or <code>true</code> if the GridView was configured
         *  with <code>allowCopy: true</code> and the control key was pressed when the drag operation was begun</div></li>
         * <li>view : GridView
         *  <div class="sub-desc">The source GridView from which the drag originated.</div></li>
         * <li>ddel : HtmlElement
         *  <div class="sub-desc">The drag proxy element which moves with the mouse</div></li>
         * <li>item : HtmlElement
         *  <div class="sub-desc">The GridView node upon which the mousedown event was registered.</div></li>
         * <li>records : Array
         *  <div class="sub-desc">An Array of {@link Ext.data.Model Model}s representing the selected data being dragged from the source GridView.</div></li>
         * </ul>
         * @param {Ext.data.Model} overModel The Model over which the drop gesture took place.
         * @param {String} dropPosition <code>"before"</code> or <code>"after"</code> depending on whether the mouse is above or below the midline of the node.
         */

        dragText : '{0} selected row{1}',

        /**
         * @cfg {String} ddGroup
         * A named drag drop group to which this object belongs.  If a group is specified, then both the DragZones and DropZone
         * used by this plugin will only interact with other drag drop objects in the same group (defaults to 'TreeDD').
         */
        ddGroup : "GridDD",

        /**
         * @cfg {String} dragGroup
         * <p>The ddGroup to which the DragZone will belong.</p>
         * <p>This defines which other DropZones the DragZone will interact with. Drag/DropZones only interact with other Drag/DropZones
         * which are members of the same ddGroup.</p>
         */

        /**
         * @cfg {String} dropGroup
         * <p>The ddGroup to which the DropZone will belong.</p>
         * <p>This defines which other DragZones the DropZone will interact with. Drag/DropZones only interact with other Drag/DropZones
         * which are members of the same ddGroup.</p>
         */

        /**
         * @cfg {Boolean} enableDrop
         * <p>Defaults to <code>true</code></p>
         * <p>Set to <code>false</code> to disallow the View from accepting drop gestures</p>
         */
        enableDrop: true,

        /**
         * @cfg {Boolean} enableDrag
         * <p>Defaults to <code>true</code></p>
         * <p>Set to <code>false</code> to disallow dragging items from the View </p>
         */
        enableDrag: true,

        init : function(view) {
            view.on('render', this.onViewRender, this, {single: true});
        },

        /**
         * @private
         * AbstractComponent calls destroy on all its plugins at destroy time.
         */
        destroy: function() {
            Ext.destroy(this.dragZone, this.dropZone);
        },

        onViewRender : function(view) {
            var me = this;

            if (me.enableDrag) {
                me.dragZone = Ext.create('Ext.view.DragZone', {
                    view: view,
                    ddGroup: me.dragGroup || me.ddGroup,
                    dragText: me.dragText
                });
            }

            if (me.enableDrop) {
                me.dropZone = Ext.create('Ext.grid.ViewDropZone', {
                    view: view,
                    ddGroup: me.dropGroup || me.ddGroup
                });
            }
        }
    });