001/*
002 * This library is part of OpenCms -
003 * the Open Source Content Management System
004 *
005 * Copyright (c) Alkacon Software GmbH & Co. KG (http://www.alkacon.com)
006 *
007 * This library is free software; you can redistribute it and/or
008 * modify it under the terms of the GNU Lesser General Public
009 * License as published by the Free Software Foundation; either
010 * version 2.1 of the License, or (at your option) any later version.
011 *
012 * This library is distributed in the hope that it will be useful,
013 * but WITHOUT ANY WARRANTY; without even the implied warranty of
014 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
015 * Lesser General Public License for more details.
016 *
017 * For further information about Alkacon Software, please see the
018 * company website: http://www.alkacon.com
019 *
020 * For further information about OpenCms, please see the
021 * project website: http://www.opencms.org
022 *
023 * You should have received a copy of the GNU Lesser General Public
024 * License along with this library; if not, write to the Free Software
025 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
026 */
027
028package org.opencms.gwt.client.dnd;
029
030import org.opencms.gwt.client.dnd.CmsDNDHandler.Orientation;
031
032import com.google.gwt.dom.client.Element;
033
034/**
035 * Interface defining all methods needed for a drag and drop target. These will mostly be called by the drag and drop handler.<p>
036 *
037 * @since 8.0.0
038 */
039public interface I_CmsDropTarget {
040
041    /**
042     * Returns true if the given cursor position is over the drop target.<p>
043     *
044     * @param x the cursor client x position
045     * @param y the cursor client y position
046     * @param orientation the drag and drop orientation
047     *
048     * @return <code>true</code> if the given cursor position is over the drop target
049     */
050    boolean checkPosition(int x, int y, Orientation orientation);
051
052    /**
053     * Returns the drop target element.<p>
054     * This must be the element, where all children will be attached.<p>
055     *
056     * @return the element
057     */
058    Element getElement();
059
060    /**
061     * Returns the index of the placeholder or -1 if no placeholder is attached.<p>
062     *
063     * @return the index
064     */
065    int getPlaceholderIndex();
066
067    /**
068     * Inserts a new placeholder.<p>
069     *
070     * @param placeholder the placeholder element
071     * @param x the cursor client x position
072     * @param y the cursor client y position
073     * @param orientation the drag and drop orientation
074     */
075    void insertPlaceholder(Element placeholder, int x, int y, Orientation orientation);
076
077    /**
078     * Executed on drop.<p>
079     *
080     * @param draggable the draggable being dropped
081     */
082    void onDrop(I_CmsDraggable draggable);
083
084    /**
085     * Removes the placeholder.<p>
086     */
087    void removePlaceholder();
088
089    /**
090     * Repositions the placeholder.<p>
091     *
092     * @param x the cursor client x position
093     * @param y the cursor client y position
094     * @param orientation the drag and drop orientation
095     */
096    void repositionPlaceholder(int x, int y, Orientation orientation);
097
098}