Droppable.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;

import com.google.gwt.dom.client.Element;
import com.google.gwt.event.shared.HasHandlers;
import com.google.gwt.query.client.GQuery;
import com.google.gwt.query.client.plugins.UiPlugin;
import com.google.gwt.query.client.plugins.Plugin;
import gwtquery.plugins.draggable.client.DragAndDropManager;

/**
 * Droppable plugin for GwtQuery
 */
public class Droppable extends UiPlugin {
    /**
     * Css class used in this plugin
     *
     * @author Julien Dramaix (julien.dramaix@gmail.com)
     */
    public static interface CssClassNames {
        String GWTQUERY_DROPPABLE = "gwtQuery-droppable";
        String GWTQUERY_DROPPABLE_DISABLED = "gwtQuery-droppable-disabled";
    }

    // A shortcut to the class
    public static final Class<Droppable> Droppable = Droppable.class;
    public static final String DROPPABLE_HANDLER_KEY = "droppableHandler";

    // Register the plugin in GQuery
    static {
        GQuery.registerPlugin(Droppable.class, new Plugin<Droppable>() {
            public Droppable init(GQuery gq) {
                return new Droppable(gq);
            }
        });
    }

    /**
     * Constructor
     *
     * @param gq
     */
    public Droppable(GQuery gq) {
        super(gq);
    }

    /**
     * Change the scope of the selected elements.
     *
     * @param newScope
     * @return
     */
    public Droppable changeScope(String newScope) {
        for (Element e : elements()) {
            DroppableHandler handler = DroppableHandler.getInstance(e);
            if (handler != null) {
                String oldScope = handler.getOptions().getScope();
                DragAndDropManager dndManager = DragAndDropManager.getInstance();
                dndManager.getDroppablesByScope(oldScope).remove(e);
                dndManager.getDroppablesByScope(newScope).add(e);
                handler.getOptions().setScope(newScope);
            }
        }
        return this;
    }

    /**
     * Remove the droppable behavior to the selectedelements. This method releases
     * resources used by the plugin and should be called when an element is
     * removed of the DOM.
     *
     * @return
     */
    public Droppable destroy() {
        DragAndDropManager ddm = DragAndDropManager.getInstance();
        for (Element e : elements()) {
            DroppableHandler infos = DroppableHandler.getInstance(e);
            ddm.getDroppablesByScope(infos.getOptions().getScope()).remove(e);
            $(e).removeClass(CssClassNames.GWTQUERY_DROPPABLE, CssClassNames.GWTQUERY_DROPPABLE_DISABLED).removeData
                    (DROPPABLE_HANDLER_KEY);
        }
        return this;
    }

    /**
     * Make the selected elements droppable with default options
     *
     * @return
     */
    public Droppable droppable() {
        return droppable(new DroppableOptions());
    }

    /**
     * Make the selected elements draggable by using the
     * <code>droppableOptions</code>
     *
     * @param droppableOptions options used to initialize the droppable
     * @return
     */
    public Droppable droppable(DroppableOptions droppableOptions) {
        return droppable(droppableOptions, null);
    }

    /**
     * Make the selected elements droppable with default options. All drop events
     * will be fired on the <code>eventBus</code>
     *
     * @param eventBus The eventBus to use to fire events.
     * @return
     */
    public Droppable droppable(HasHandlers eventBus) {
        return droppable(new DroppableOptions(), eventBus);
    }

    /**
     * Make the selected elements droppable by using the
     * <code>droppableOptions</code>. All drop events will be fired on the
     * <code>eventBus</code>
     *
     * @param eventBus         The eventBus to use to fire events.
     * @param droppableOptions options used to initialize the droppable
     * @return
     */
    public Droppable droppable(DroppableOptions droppableOptions, HasHandlers eventBus) {

        DragAndDropManager ddm = DragAndDropManager.getInstance();

        for (Element e : elements()) {
            DroppableHandler handler = new DroppableHandler(droppableOptions, eventBus);
            handler.setDroppableDimension(new Dimension(e));
            $(e).data(DROPPABLE_HANDLER_KEY, handler);

            ddm.addDroppable(e, droppableOptions.getScope());

            e.addClassName(CssClassNames.GWTQUERY_DROPPABLE);
        }

        return this;
    }

    /**
     * Get the {@link DroppableOptions} for the first element.
     *
     * @return
     */
    public DroppableOptions options() {
        if (length() > 0) {
            DroppableHandler handler = DroppableHandler.getInstance(get(0));
            if (handler != null) {
                return handler.getOptions();
            }
        }
        return null;
    }

    /**
     * Set the {@link DroppableOptions} for the selected elements.
     *
     * @return
     */
    public Droppable options(DroppableOptions options) {
        if (length() > 0) {
            DroppableHandler handler = DroppableHandler.getInstance(get(0));
            if (handler != null) {
                handler.setOptions(options);
            }
        }
        return this;
    }
}