| /* |
| * Copyright (c) 2005, 2008, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code 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 General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| package javax.swing.plaf.basic; |
| |
| import java.awt.Toolkit; |
| import java.awt.event.*; |
| import java.awt.dnd.DragSource; |
| import javax.swing.*; |
| import sun.awt.dnd.SunDragSourceContextPeer; |
| import sun.awt.AppContext; |
| |
| /** |
| * Drag gesture recognition support for classes that have a |
| * <code>TransferHandler</code>. The gesture for a drag in this class is a mouse |
| * press followed by movement by <code>DragSource.getDragThreshold()</code> |
| * pixels. An instance of this class is maintained per AppContext, and the |
| * public static methods call into the appropriate instance. |
| * |
| * @author Shannon Hickey |
| */ |
| class DragRecognitionSupport { |
| private int motionThreshold; |
| private MouseEvent dndArmedEvent; |
| private JComponent component; |
| |
| /** |
| * This interface allows us to pass in a handler to mouseDragged, |
| * so that we can be notified immediately before a drag begins. |
| */ |
| public static interface BeforeDrag { |
| public void dragStarting(MouseEvent me); |
| } |
| |
| /** |
| * Returns the DragRecognitionSupport for the caller's AppContext. |
| */ |
| private static DragRecognitionSupport getDragRecognitionSupport() { |
| DragRecognitionSupport support = |
| (DragRecognitionSupport)AppContext.getAppContext(). |
| get(DragRecognitionSupport.class); |
| |
| if (support == null) { |
| support = new DragRecognitionSupport(); |
| AppContext.getAppContext().put(DragRecognitionSupport.class, support); |
| } |
| |
| return support; |
| } |
| |
| /** |
| * Returns whether or not the event is potentially part of a drag sequence. |
| */ |
| public static boolean mousePressed(MouseEvent me) { |
| return getDragRecognitionSupport().mousePressedImpl(me); |
| } |
| |
| /** |
| * If a dnd recognition has been going on, return the MouseEvent |
| * that started the recognition. Otherwise, return null. |
| */ |
| public static MouseEvent mouseReleased(MouseEvent me) { |
| return getDragRecognitionSupport().mouseReleasedImpl(me); |
| } |
| |
| /** |
| * Returns whether or not a drag gesture recognition is ongoing. |
| */ |
| public static boolean mouseDragged(MouseEvent me, BeforeDrag bd) { |
| return getDragRecognitionSupport().mouseDraggedImpl(me, bd); |
| } |
| |
| private void clearState() { |
| dndArmedEvent = null; |
| component = null; |
| } |
| |
| private int mapDragOperationFromModifiers(MouseEvent me, |
| TransferHandler th) { |
| |
| if (th == null || !SwingUtilities.isLeftMouseButton(me)) { |
| return TransferHandler.NONE; |
| } |
| |
| return SunDragSourceContextPeer. |
| convertModifiersToDropAction(me.getModifiersEx(), |
| th.getSourceActions(component)); |
| } |
| |
| /** |
| * Returns whether or not the event is potentially part of a drag sequence. |
| */ |
| private boolean mousePressedImpl(MouseEvent me) { |
| component = (JComponent)me.getSource(); |
| |
| if (mapDragOperationFromModifiers(me, component.getTransferHandler()) |
| != TransferHandler.NONE) { |
| |
| motionThreshold = DragSource.getDragThreshold(); |
| dndArmedEvent = me; |
| return true; |
| } |
| |
| clearState(); |
| return false; |
| } |
| |
| /** |
| * If a dnd recognition has been going on, return the MouseEvent |
| * that started the recognition. Otherwise, return null. |
| */ |
| private MouseEvent mouseReleasedImpl(MouseEvent me) { |
| /* no recognition has been going on */ |
| if (dndArmedEvent == null) { |
| return null; |
| } |
| |
| MouseEvent retEvent = null; |
| |
| if (me.getSource() == component) { |
| retEvent = dndArmedEvent; |
| } // else component has changed unexpectedly, so return null |
| |
| clearState(); |
| return retEvent; |
| } |
| |
| /** |
| * Returns whether or not a drag gesture recognition is ongoing. |
| */ |
| private boolean mouseDraggedImpl(MouseEvent me, BeforeDrag bd) { |
| /* no recognition is in progress */ |
| if (dndArmedEvent == null) { |
| return false; |
| } |
| |
| /* component has changed unexpectedly, so bail */ |
| if (me.getSource() != component) { |
| clearState(); |
| return false; |
| } |
| |
| int dx = Math.abs(me.getX() - dndArmedEvent.getX()); |
| int dy = Math.abs(me.getY() - dndArmedEvent.getY()); |
| if ((dx > motionThreshold) || (dy > motionThreshold)) { |
| TransferHandler th = component.getTransferHandler(); |
| int action = mapDragOperationFromModifiers(me, th); |
| if (action != TransferHandler.NONE) { |
| /* notify the BeforeDrag instance */ |
| if (bd != null) { |
| bd.dragStarting(dndArmedEvent); |
| } |
| th.exportAsDrag(component, dndArmedEvent, action); |
| clearState(); |
| } |
| } |
| |
| return true; |
| } |
| } |