DragAndDropCellWidgetUtils.java

/*
 * Copyright 2010 The gwtquery plugins team.
 * 
 * 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.
 */
package gwtquery.plugins.droppable.client.gwt;

import static com.google.gwt.query.client.GQuery.$;
import static gwtquery.plugins.draggable.client.Draggable.Draggable;
import static gwtquery.plugins.droppable.client.Droppable.Droppable;

import com.google.gwt.dom.client.Element;
import com.google.gwt.event.shared.EventBus;
import com.google.gwt.query.client.GQuery;
import gwtquery.plugins.draggable.client.DraggableHandler;
import gwtquery.plugins.draggable.client.DraggableOptions;
import gwtquery.plugins.droppable.client.DroppableHandler;
import gwtquery.plugins.droppable.client.DroppableOptions;

/**
 * Utils class with all code used in CellWidget to manage
 * the drag and drop behavior of cells
 *
 * @author Julien Dramaix (julien.dramaix@gmail.com)
 */
public class DragAndDropCellWidgetUtils {
    public static final String VALUE_KEY = "__dragAndDropCellAssociatedValue";
    private static final DragAndDropCellWidgetUtils INSTANCE = new DragAndDropCellWidgetUtils();

    static DragAndDropCellWidgetUtils get() {
        return INSTANCE;
    }

    private DragAndDropCellWidgetUtils() {
    }

    void cleanCell(Element cell) {

        if (cell == null) {
            return;
        }

        GQuery $cell = $(cell);

        if (DraggableHandler.getInstance(cell) != null) {
            $cell.as(Draggable).destroy();
        }

        if (DroppableHandler.getInstance(cell) != null) {
            $cell.as(Droppable).destroy();
        }

        $cell.removeData(VALUE_KEY);
    }

    <C> void maybeMakeDraggableOrDroppable(Element cell, C value, CellDragAndDropBehaviour<C>
            cellDragAndDropBehaviour, DraggableOptions draggableOptions, DroppableOptions droppableOptions, EventBus
            eventBus) {

        GQuery $cell = $(cell);

        if ((cellDragAndDropBehaviour == null || cellDragAndDropBehaviour.isDraggable(value)) && DraggableHandler
                .getInstance(cell) == null) {

            $cell.as(Draggable).draggable(draggableOptions, eventBus);
        }

        if ((cellDragAndDropBehaviour == null || cellDragAndDropBehaviour.isDroppable(value)) && DroppableHandler
                .getInstance(cell) == null) {

            $cell.as(Droppable).droppable(droppableOptions, eventBus);
        }

        $cell.data(VALUE_KEY, value);
    }
}