Java tutorial
/* * * Copyright (C) 2007-2015 Licensed to the Comunes Association (CA) under * one or more contributor license agreements (see COPYRIGHT for details). * The CA licenses this file to you under the GNU Affero General Public * License version 3, (the "License"); you may not use this file except in * compliance with the License. This file is part of kune. * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU Affero General Public License as * published by the Free Software Foundation, either version 3 of the * License, or (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU Affero General Public License for more details. * * You should have received a copy of the GNU Affero General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. * */ package cc.kune.core.client.dnd; import java.util.ArrayList; import java.util.List; import cc.kune.common.client.actions.ui.descrip.DropTarget; import com.allen_sauer.gwt.dnd.client.DragContext; import com.allen_sauer.gwt.dnd.client.VetoDragException; import com.allen_sauer.gwt.dnd.client.drop.SimpleDropController; import com.google.gwt.event.logical.shared.AttachEvent; import com.google.gwt.event.logical.shared.AttachEvent.Handler; import com.google.gwt.user.client.ui.Widget; // TODO: Auto-generated Javadoc /** * The Class AbstractDropController. * * @author vjrj@ourproject.org (Vicente J. Ruiz Jurado) */ public abstract class AbstractDropController implements DropTarget { /** The accepted types (which one we allow to drop here). */ private final List<Class<?>> acceptedTypes; /** The drag controller. */ private final KuneDragController dragController; /** The drop controller. */ private SimpleDropController dropController; /** The target. */ private Object target; /** * Instantiates a new abstract drop controller. * * @param dragController * the drag controller */ public AbstractDropController(final KuneDragController dragController) { this.dragController = dragController; acceptedTypes = new ArrayList<Class<?>>(); } /** * Gets the target. * * @return the target */ public Object getTarget() { return target; } /* * (non-Javadoc) * * @see * cc.kune.common.client.actions.ui.descrip.DropTarget#init(com.google.gwt * .user.client.ui.Widget) */ @Override public void init(final Widget dropTarget) { dropController = new SimpleDropController(dropTarget) { @Override public void onDrop(final DragContext context) { boolean droppedSomething = false; super.onDrop(context); for (final Widget widget : context.selectedWidgets) { if (acceptedTypes.contains(widget.getClass())) { onDropAllowed(widget, this); droppedSomething = true; } } if (droppedSomething) { onGroupDropFinished(this); } } @Override public void onEnter(final DragContext context) { super.onEnter(context); for (final Widget widget : context.selectedWidgets) { if (acceptedTypes.contains(widget.getClass())) { onEnterAllowed(this); } } } @Override public void onLeave(final DragContext context) { super.onLeave(context); for (final Widget widget : context.selectedWidgets) { if (acceptedTypes.contains(widget.getClass())) { onLeaveAllowed(this); } } } @Override public void onPreviewDrop(final DragContext context) throws VetoDragException { for (final Widget widget : context.selectedWidgets) { if (acceptedTypes.contains(widget.getClass())) { onPreviewAllowed(widget, this); } else { throw new VetoDragException(); } } super.onPreviewDrop(context); } }; dropTarget.addStyleName("k-drop-allowed"); if (dropTarget.isAttached()) { dragController.registerDropController(dropController); } dropTarget.addAttachHandler(new Handler() { @Override public void onAttachOrDetach(final AttachEvent event) { if (!event.isAttached()) { dragController.unregisterDropController(dropController); } else { dragController.registerDropController(dropController); } } }); } /** * On drop allowed. * * @param widget * the widget * @param dropController * the drop controller */ public abstract void onDropAllowed(Widget widget, final SimpleDropController dropController); /** * On enter allowed. * * @param dropController * the drop controller */ public void onEnterAllowed(final SimpleDropController dropController) { dropController.getDropTarget().addStyleName("k-drop-allowed-hover"); } /** * On group drop finished, is fired when all the widgets are dropped (at the * end). * * @param dropController * the drop controller */ public void onGroupDropFinished(final SimpleDropController dropController) { } /** * On leave allowed. * * @param dropController * the drop controller */ public void onLeaveAllowed(final SimpleDropController dropController) { dropController.getDropTarget().removeStyleName("k-drop-allowed-hover"); } /** * On preview allowed. * * @param widget * the widget * @param dropController * the drop controller * @throws VetoDragException * the veto drag exception */ public void onPreviewAllowed(final Widget widget, final SimpleDropController dropController) throws VetoDragException { dropController.getDropTarget().removeStyleName("k-drop-allowed-hover"); } /** * Register type to accept this kind of widgets to be dropped here. * * @param classType * the class type */ public void registerType(final Class<?> classType) { acceptedTypes.add(classType); } /** * Sets the target (for instance a StateToken id, to perform operations), * because with the widget we don't have all the info. * * @param target * the new target */ public void setTarget(final Object target) { this.target = target; } }