com.sencha.gxt.dnd.core.client.GridDragSource.java Source code

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Here is the source code for com.sencha.gxt.dnd.core.client.GridDragSource.java

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/**
 * Sencha GXT 4.0.0 - Sencha for GWT
 * Copyright (c) 2006-2015, Sencha Inc.
 *
 * licensing@sencha.com
 * http://www.sencha.com/products/gxt/license/
 *
 * ================================================================================
 * Open Source License
 * ================================================================================
 * This version of Sencha GXT is licensed under the terms of the Open Source GPL v3
 * license. You may use this license only if you are prepared to distribute and
 * share the source code of your application under the GPL v3 license:
 * http://www.gnu.org/licenses/gpl.html
 *
 * If you are NOT prepared to distribute and share the source code of your
 * application under the GPL v3 license, other commercial and oem licenses
 * are available for an alternate download of Sencha GXT.
 *
 * Please see the Sencha GXT Licensing page at:
 * http://www.sencha.com/products/gxt/license/
 *
 * For clarification or additional options, please contact:
 * licensing@sencha.com
 * ================================================================================
 *
 *
 * ================================================================================
 * Disclaimer
 * ================================================================================
 * THIS SOFTWARE IS DISTRIBUTED "AS-IS" WITHOUT ANY WARRANTIES, CONDITIONS AND
 * REPRESENTATIONS WHETHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION THE
 * IMPLIED WARRANTIES AND CONDITIONS OF MERCHANTABILITY, MERCHANTABLE QUALITY,
 * FITNESS FOR A PARTICULAR PURPOSE, DURABILITY, NON-INFRINGEMENT, PERFORMANCE AND
 * THOSE ARISING BY STATUTE OR FROM CUSTOM OR USAGE OF TRADE OR COURSE OF DEALING.
 * ================================================================================
 */
package com.sencha.gxt.dnd.core.client;

import java.util.List;

import com.google.gwt.dom.client.Element;
import com.google.gwt.safehtml.shared.SafeHtmlUtils;
import com.sencha.gxt.core.client.util.Format;
import com.sencha.gxt.dnd.core.client.DND.Operation;
import com.sencha.gxt.messages.client.DefaultMessages;
import com.sencha.gxt.widget.core.client.grid.Grid;

/**
 * Enables a {@link Grid} to act as the source of a drag and drop operation.
 * <p/>
 * The drag data consists of a list of items of type {@code <M>}.
 * 
 * @param <M> the model type
 */
public class GridDragSource<M> extends DragSource {

    /**
     * The locale-sensitive messages used by this class.
     */
    public interface GridDragSourceMessages {

        /**
         * Returns a message indicating the number of items selected.
         * 
         * @param items the number of items selected
         * @return a message indicating the number of items selected
         */
        String itemsSelected(int items);
    }

    protected class DefaultGridDragSourceMessages implements GridDragSourceMessages {

        @Override
        public String itemsSelected(int items) {
            return DefaultMessages.getMessages().listField_itemsSelected(items);
        }

    }

    protected Grid<M> grid;

    private GridDragSourceMessages messages;

    /**
     * Creates a drag source for the specified grid.
     * 
     * @param grid the grid to enable as a drag source
     */
    public GridDragSource(Grid<M> grid) {
        super(grid);
        this.grid = grid;
    }

    /**
     * Returns the grid associated with this drag source.
     * 
     * @return the grid associated with this drag source
     */
    public Grid<M> getGrid() {
        return grid;
    }

    /**
     * Returns the locale-sensitive messages used by this class.
     * 
     * @return the locale-sensitive messages used by this class
     */
    public GridDragSourceMessages getMessages() {
        if (messages == null) {
            messages = new DefaultGridDragSourceMessages();
        }
        return messages;
    }

    /**
     * Sets the local-sensitive messages used by this class.
     * 
     * @param messages the locale sensitive messages used by this class.
     */
    public void setMessages(GridDragSourceMessages messages) {
        this.messages = messages;
    }

    @Override
    protected void onDragDrop(DndDropEvent event) {
        if (event.getOperation() == Operation.MOVE) {
            Object data = event.getData();
            if (data instanceof List) {
                @SuppressWarnings("unchecked")
                List<M> list = (List<M>) data;
                for (M item : list) {
                    grid.getStore().remove(item);
                }
            }
            super.data = null;
        }
    }

    @Override
    protected void onDragStart(DndDragStartEvent event) {
        Element r = grid.getView().findRow(event.getDragStartEvent().getStartElement()).cast();
        if (r == null) {
            event.setCancelled(true);
            return;
        }
        List<M> sel = grid.getSelectionModel().getSelectedItems();
        if (sel.size() > 0) {
            event.setCancelled(false);
            event.setData(sel);

            if (getStatusText() == null) {
                event.getStatusProxy().update(SafeHtmlUtils.fromString(getMessages().itemsSelected(sel.size())));
            } else {
                event.getStatusProxy()
                        .update(SafeHtmlUtils.fromString(Format.substitute(getStatusText(), sel.size())));
            }
        }
    }

}