/*
* $Id$
*
* Copyright 2009 Sun Microsystems, Inc., 4150 Network Circle,
* Santa Clara, California 95054, U.S.A. All rights reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
*/
package org.jdesktop.swingx.plaf.basic.core;
/*
* @(#)DragRecognitionSupport.java 1.2 05/11/17
*
* Copyright 2006 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
import java.awt.Toolkit;
import java.awt.event.*;
import java.awt.dnd.DragSource;
import javax.swing.*;
import org.jdesktop.swingx.SwingXUtilities;
//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. <p>
*
* This is a c&p of core (package private) needed for BasicXListUI. It differs from
* core in that references to sun packages have been replaced.
* <ul>
* <li> a static method of SunDragSourceContextPeer has been copied into SwingXUtilities
* and is used here
* <li> the shared instance of this class is maintained in the UIManager instead of
* per appContext.
* </ul>
*
* @author Shannon Hickey
* @version 1.2 11/17/05
*/
public 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);
// }
DragRecognitionSupport support = (DragRecognitionSupport)
UIManager.get("sharedInstance.dragRecognitionSupport");
if (support == null) {
support = new DragRecognitionSupport();
UIManager.put("sharedInstance.dragRecognitionSupport", support);
}
return support;
}
/**
* Returns whether or not the event is potentially part of a drag sequence.
*/
public static boolean mousePressed(MouseEvent me) {
return ((DragRecognitionSupport)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 ((DragRecognitionSupport)getDragRecognitionSupport()).
mouseReleasedImpl(me);
}
/**
* Returns whether or not a drag gesture recognition is ongoing.
*/
public static boolean mouseDragged(MouseEvent me, BeforeDrag bd) {
return ((DragRecognitionSupport)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;
}
// PENDING JW: c'p from SunDragSourceContextPeer
return SwingXUtilities.
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;
}
}