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org.jvnet.lafwidget.tree.dnd.TreeDragAndDropWidget Maven / Gradle / Ivy
Laf-Widget provides support for common "feel" widgets in look-and-feel libraries
/*
* Copyright (c) 2005-2006 Laf-Widget Kirill Grouchnikov. All Rights Reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* o Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* o Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* o Neither the name of Laf-Widget Kirill Grouchnikov nor the names of
* its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
* OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package org.jvnet.lafwidget.tree.dnd;
import java.awt.*;
import java.awt.datatransfer.*;
import java.awt.dnd.*;
import java.awt.image.BufferedImage;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.lang.reflect.Method;
import java.util.Enumeration;
import java.util.EventListener;
import javax.swing.JComponent;
import javax.swing.JTree;
import javax.swing.event.EventListenerList;
import javax.swing.tree.*;
import org.jvnet.lafwidget.*;
/**
* TreeWrapper is used to handle drag and drop and popup menus in any JTree.
*
* @author Antonio Vieiro ([email protected] ), $Author: kirillcool $
* @version $Revision: 1.7 $
*/
public class TreeDragAndDropWidget extends LafWidgetAdapter {
/**
* This to avoid excesive creation of objects in invocation.
*/
private static Class[] EMPTY_CLASS_ARRAY = new Class[0];
/**
* This to avoid excessive reflection to find the "getTransferable" method.
*/
private static Method getTransferableMethod = null;
/**
* This to avoid excesive creation of objects in invocation.
*/
private static Object[] EMPTY_OBJECT_ARRAY = new Object[0];
protected JTree tree;
protected DnDCellRendererProxy rendererProxy;
protected DragSource dragSource;
protected DropTarget dropTarget;
protected MutableTreeNode dropNode;
protected EventListenerList listeners;
protected PropertyChangeListener propertyChangeListener;
protected PropertyChangeListener cellRendererChangeListener;
protected TreeDropTargetListener dropListener;
protected TreeDragGestureListener gestureListener;
protected DragGestureRecognizer dragGestureRecognizer;
/*
* (non-Javadoc)
*
* @see org.jvnet.lafwidget.LafWidget#requiresCustomLafSupport()
*/
public boolean requiresCustomLafSupport() {
return false;
}
/*
* (non-Javadoc)
*
* @see org.jvnet.lafwidget.LafWidgetAdapter#setComponent(javax.swing.JComponent)
*/
public void setComponent(JComponent jcomp) {
super.setComponent(jcomp);
this.tree = (JTree) jcomp;
}
/*
* (non-Javadoc)
*
* @see org.jvnet.lafwidget.LafWidgetAdapter#installListeners()
*/
public void installListeners() {
this.listeners = new EventListenerList();
this.propertyChangeListener = new PropertyChangeListener() {
public void propertyChange(PropertyChangeEvent evt) {
if (LafWidget.TREE_AUTO_DND_SUPPORT.equals(evt
.getPropertyName())) {
Object oldValue = evt.getOldValue();
Object newValue = evt.getNewValue();
boolean hadDnd = false;
if (oldValue instanceof Boolean)
hadDnd = ((Boolean) oldValue).booleanValue();
boolean hasDnd = false;
if (newValue instanceof Boolean)
hasDnd = ((Boolean) newValue).booleanValue();
if (!hadDnd && hasDnd && TreeDragAndDropWidget.this.tree.isEnabled()) {
TreeDragAndDropWidget.this.installDnDSupport();
}
if (hadDnd && !hasDnd) {
TreeDragAndDropWidget.this.uninstallDnDSupport();
}
}
if ("enabled".equals(evt.getPropertyName())) {
boolean wasEnabled = ((Boolean) evt.getOldValue())
.booleanValue();
boolean isEnabled = ((Boolean) evt.getNewValue())
.booleanValue();
if (!wasEnabled && isEnabled) {
if (LafWidgetUtilities.hasAutomaticDnDSupport(TreeDragAndDropWidget.this.tree))
TreeDragAndDropWidget.this.installDnDSupport();
}
if (wasEnabled && !isEnabled)
TreeDragAndDropWidget.this.uninstallDnDSupport();
}
}
};
this.tree.addPropertyChangeListener(this.propertyChangeListener);
if (this.tree.isEnabled()
&& LafWidgetUtilities.hasAutomaticDnDSupport(this.tree))
this.installDnDSupport();
}
private void installDnDSupport() {
if (this.cellRendererChangeListener != null) {
// already installed.
return;
}
this.cellRendererChangeListener = new PropertyChangeListener() {
public void propertyChange(PropertyChangeEvent evt) {
String name = evt.getPropertyName();
if (name.equals(JTree.CELL_RENDERER_PROPERTY)) {
TreeCellRenderer renderer = TreeDragAndDropWidget.this.tree.getCellRenderer();
if (!(renderer instanceof DnDCellRendererProxy)) {
TreeDragAndDropWidget.this.rendererProxy = new DnDCellRendererProxy(renderer);
TreeDragAndDropWidget.this.tree.setCellRenderer(TreeDragAndDropWidget.this.rendererProxy);
TreeDragAndDropWidget.this.tree.repaint();
} else
TreeDragAndDropWidget.this.rendererProxy = (DnDCellRendererProxy) renderer;
}
}
};
this.tree.addPropertyChangeListener(this.cellRendererChangeListener);
if (this.tree.getCellRenderer() != null) {
this.tree.setCellRenderer(new DnDCellRendererProxy(this.tree
.getCellRenderer()));
}
this.dragSource = new DragSource();
this.gestureListener = new TreeDragGestureListener();
this.dragGestureRecognizer = this.dragSource
.createDefaultDragGestureRecognizer(this.tree,
DnDConstants.ACTION_COPY_OR_MOVE, this.gestureListener);
this.dropListener = new TreeDropTargetListener();
this.dropTarget = new AutoScrollingTreeDropTarget(this.tree,
this.dropListener);
}
/*
* (non-Javadoc)
*
* @see org.jvnet.lafwidget.LafWidgetAdapter#uninstallListeners()
*/
public void uninstallListeners() {
this.tree.removePropertyChangeListener(this.propertyChangeListener);
this.propertyChangeListener = null;
this.uninstallDnDSupport();
}
private void uninstallDnDSupport() {
if (this.cellRendererChangeListener != null) {
this.tree
.removePropertyChangeListener(this.cellRendererChangeListener);
this.cellRendererChangeListener = null;
}
TreeCellRenderer tcl = this.tree.getCellRenderer();
if (tcl instanceof DnDCellRendererProxy) {
TreeCellRenderer origRenderer = ((DnDCellRendererProxy) tcl)
.getOriginalTreeCellRenderer();
this.tree.setCellRenderer(origRenderer);
}
if (this.dropListener != null) {
this.dropTarget.removeDropTargetListener(this.dropListener);
this.dropListener = null;
this.tree.setDropTarget(null);
}
if (this.dragGestureRecognizer != null) {
this.dragGestureRecognizer
.removeDragGestureListener(this.gestureListener);
this.gestureListener = null;
this.dragGestureRecognizer = null;
}
}
/**
* Internal class that implements DragGestureListener.
*/
class TreeDragGestureListener implements DragGestureListener {
public void dragGestureRecognized(DragGestureEvent dge) {
// If tree is disabled then discard drag from it
if (!TreeDragAndDropWidget.this.tree.isEnabled())
return;
// Select the node that the user is trying to drag, if any.
TreePath draggedPath = TreeDragAndDropWidget.this.tree.getClosestPathForLocation(dge
.getDragOrigin().x, dge.getDragOrigin().y);
if (draggedPath == null)
return;
TreeNode node = (TreeNode) draggedPath.getLastPathComponent();
if ((node instanceof MutableTreeNode) && (node.getParent() != null)
&& (node.getParent() instanceof MutableTreeNode))
;
else
return;
// Prepare the node for transfer
TransferableTreeNode transferableNode = new TransferableTreeNode(
TreeDragAndDropWidget.this.tree, (MutableTreeNode) node, TreeDragAndDropWidget.this.tree.isExpanded(draggedPath));
TreeDragAndDropWidget.this.rendererProxy.setDraggedNode(node);
// Initialize the drag. If isDragImageSupported then build a
// transparent image
BufferedImage image = null;
Point imageOffset = null;
// Create an image with the dragged node.
TreeCellRenderer renderer = TreeDragAndDropWidget.this.rendererProxy
.getOriginalTreeCellRenderer();
Rectangle dragBounds = TreeDragAndDropWidget.this.tree.getPathBounds(draggedPath);
imageOffset = new Point(dge.getDragOrigin().x - dragBounds.x, dge
.getDragOrigin().y
- dragBounds.y);
Component component = renderer.getTreeCellRendererComponent(TreeDragAndDropWidget.this.tree,
node, false, TreeDragAndDropWidget.this.tree.isExpanded(draggedPath), node.isLeaf(),
0, false);
component.setSize(dragBounds.width, dragBounds.height);
image = new BufferedImage(dragBounds.width, dragBounds.height,
BufferedImage.TYPE_INT_ARGB);
Graphics2D g2d = image.createGraphics();
g2d.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC,
0.75f));
component.paint(g2d);
g2d.dispose();
// Initiate the drag
if (DragSource.isDragImageSupported()) {
TreeDragAndDropWidget.this.dragSource.startDrag(dge, null, image, imageOffset,
transferableNode, new TreeDragSourceListener());
} else {
TreeDragAndDropWidget.this.dragSource.startDrag(dge, null, transferableNode,
new TreeDragSourceListener());
}
}
}
/**
* Internal class that implements DragSourceListener.
*/
class TreeDragSourceListener implements DragSourceListener {
public void dragExit(DragSourceEvent dse) {
// dropNode = null;
// rendererProxy.setDropNode( null );
// tree.repaint();
}
public void dropActionChanged(DragSourceDragEvent dsde) {
}
public void dragOver(DragSourceDragEvent dsde) {
}
public void dragEnter(DragSourceDragEvent dsde) {
}
public void dragDropEnd(DragSourceDropEvent dsde) {
TreeDragAndDropWidget.this.resetDragAndDrop();
}
}
class TreeDropTargetListener implements DropTargetListener {
public void drop(DropTargetDropEvent dtde) {
TreePath dropPath = TreeDragAndDropWidget.this.tree.getClosestPathForLocation(dtde
.getLocation().x, dtde.getLocation().y);
if (!TreeDragAndDropWidget.this.tree.isEnabled() || (dropPath == null)) {
dtde.rejectDrop();
dtde.dropComplete(false);
TreeDragAndDropWidget.this.resetDragAndDrop();
return;
}
TreeDragAndDropWidget.this.dropNode = (MutableTreeNode) dropPath.getLastPathComponent();
// Handle dropping java JVM local objects (tree nodes)
try {
dtde.acceptDrop(DnDConstants.ACTION_COPY_OR_MOVE);
// Are we dropping a JVM local object?
TransferableTreeNode ttn = (TransferableTreeNode) dtde
.getTransferable().getTransferData(
TransferableTreeNode
.getJavaJVMLocalObjectFlavor());
JTree sourceTree = ttn.getSourceTree();
MutableTreeNode sourceNode = ttn.getSourceNode();
if (TreeDragAndDropWidget.this.mayDropHere(sourceTree, sourceNode, TreeDragAndDropWidget.this.dropNode)) {
dtde.dropComplete(this.dropNodes(ttn.getSourceTree(), ttn
.getSourceNode(), TreeDragAndDropWidget.this.tree, TreeDragAndDropWidget.this.dropNode, (dtde
.getDropAction() & DnDConstants.ACTION_MOVE) != 0));
if (ttn.isNodeWasExpanded()) {
DefaultTreeModel targetModel = (DefaultTreeModel) TreeDragAndDropWidget.this.tree
.getModel();
TreeDragAndDropWidget.this.tree.expandPath(new TreePath(targetModel
.getPathToRoot(ttn.getSourceNode())));
}
TreeDragAndDropWidget.this.resetDragAndDrop();
} else {
try {
dtde.rejectDrop();
} catch (Exception e) {
// An exception may be thrown here if the user leaves
// and enters the window.
// This is an exceptional case.
}
dtde.dropComplete(false);
TreeDragAndDropWidget.this.resetDragAndDrop();
return;
}
} catch (UnsupportedFlavorException ufe) {
// So this is not a JVM local object, maybe it's a String...
try {
String droppedString = (String) dtde.getTransferable()
.getTransferData(DataFlavor.stringFlavor);
if (TreeDragAndDropWidget.this.mayDropHere(droppedString, TreeDragAndDropWidget.this.tree, dropPath)) {
dtde.dropComplete(this.dropString(droppedString));
TreeDragAndDropWidget.this.resetDragAndDrop();
} else {
dtde.rejectDrop();
dtde.dropComplete(false);
TreeDragAndDropWidget.this.resetDragAndDrop();
return;
}
} catch (Exception exception) {
dtde.rejectDrop();
dtde.dropComplete(false);
TreeDragAndDropWidget.this.resetDragAndDrop();
return;
}
} catch (Exception e) {
// ClassCastException: So this is a JVM local object but not a
// TransferableTreeNode, right? Well, then just discard
// IOException: So there's a problem deserializing this, right?
// Well, then just discard
e.printStackTrace();
dtde.rejectDrop();
dtde.dropComplete(true);
TreeDragAndDropWidget.this.resetDragAndDrop();
return;
}
}
private boolean dropString(String droppedString) {
// Get the mutable TreeModel
DefaultTreeModel model = (DefaultTreeModel) TreeDragAndDropWidget.this.tree.getModel();
// Ask the listeners to handle this drop
boolean doItOurselves = true;
EventListener[] listeners = TreeDragAndDropWidget.this.listeners
.getListeners(StringTreeDnDListener.class);
if ((listeners != null) && (listeners.length > 0)) {
try {
StringTreeDnDEvent event = new StringTreeDnDEvent(
droppedString, TreeDragAndDropWidget.this.tree, TreeDragAndDropWidget.this.dropNode);
for (int i = 0; i < listeners.length; i++) {
((StringTreeDnDListener) listeners[i]).drop(event);
}
} catch (DnDVetoException exception) {
doItOurselves = true;
}
}
if (doItOurselves) {
DefaultMutableTreeNode newNode = new DefaultMutableTreeNode(
droppedString);
MutableTreeNode parent = (MutableTreeNode) TreeDragAndDropWidget.this.dropNode.getParent();
if (TreeDragAndDropWidget.this.dropNode.isLeaf()) {
int index = parent.getIndex(TreeDragAndDropWidget.this.dropNode);
model.insertNodeInto(newNode, parent, index + 1);
} else {
model.insertNodeInto(newNode, TreeDragAndDropWidget.this.dropNode, 0); // dropNode.getChildCount()
// );
}
}
return true;
}
private boolean dropNodes(JTree aSourceTree,
MutableTreeNode aSourceNode, JTree aTargetTree,
MutableTreeNode aDropNode, boolean move) {
// Get the mutable TreeModel
DefaultTreeModel sourceModel = (DefaultTreeModel) aSourceTree
.getModel();
DefaultTreeModel targetModel = (DefaultTreeModel) aTargetTree
.getModel();
boolean doItOurselves = true;
EventListener[] listeners = TreeDragAndDropWidget.this.listeners
.getListeners(TreeTreeDnDListener.class);
if ((listeners != null) && (listeners.length > 0)) {
try {
TreeTreeDnDEvent event = new TreeTreeDnDEvent(aSourceTree,
aSourceNode, aTargetTree, aDropNode);
for (int i = 0; i < listeners.length; i++) {
((TreeTreeDnDListener) listeners[i]).drop(event);
}
} catch (DnDVetoException exception) {
doItOurselves = false;
}
}
if (doItOurselves) {
MutableTreeNode sourceNodeCopy = aSourceNode;
if (move) {
sourceModel.removeNodeFromParent(aSourceNode);
} else {
sourceNodeCopy = this.recursivelyCopyNodes(targetModel,
aSourceNode);
}
// Attach the draggedNode into the new parent
MutableTreeNode parent = (MutableTreeNode) aDropNode
.getParent();
if (aDropNode.isLeaf() && (parent != null)) {
int index = parent.getIndex(aDropNode);
targetModel.insertNodeInto(sourceNodeCopy, parent,
index + 1);
} else {
targetModel.insertNodeInto(sourceNodeCopy, aDropNode, 0);// aDropNode.getChildCount()
// );
}
}
return true;
}
private DefaultMutableTreeNode recursivelyCopyNodes(
DefaultTreeModel aModel, TreeNode aNode) {
DefaultMutableTreeNode copy = new DefaultMutableTreeNode(aNode
.toString());
copy.setAllowsChildren(aNode.getAllowsChildren());
if (aNode.getChildCount() != 0) {
Enumeration children = aNode.children();
while (children.hasMoreElements()) {
TreeNode child = (TreeNode) children.nextElement();
DefaultMutableTreeNode childCopy = this.recursivelyCopyNodes(
aModel, child);
aModel
.insertNodeInto(childCopy, copy, copy
.getChildCount());
childCopy.setParent(copy);
}
}
return copy;
}
public void dragExit(DropTargetEvent dte) {
TreeDragAndDropWidget.this.dropNode = null;
TreeDragAndDropWidget.this.rendererProxy.setDropNode(null);
TreeDragAndDropWidget.this.tree.repaint();
}
public void dropActionChanged(DropTargetDragEvent dtde) {
}
private Transferable getTransferable(DropTargetDragEvent dtde) {
try {
DropTargetContext context = dtde.getDropTargetContext();
if (TreeDragAndDropWidget.getTransferableMethod == null) {
TreeDragAndDropWidget.getTransferableMethod = context.getClass()
.getDeclaredMethod("getTransferable",
TreeDragAndDropWidget.EMPTY_CLASS_ARRAY);
TreeDragAndDropWidget.getTransferableMethod.setAccessible(true);
}
return (Transferable) TreeDragAndDropWidget.getTransferableMethod.invoke(context,
TreeDragAndDropWidget.EMPTY_OBJECT_ARRAY);
} catch (Exception e) {
e.printStackTrace(System.err);
return null;
}
}
/** This node to avoid too many invocations to dragOver */
private TreeNode lastDragOverNode = null;
public void dragOver(DropTargetDragEvent dtde) {
if (!TreeDragAndDropWidget.this.tree.isEnabled()) {
dtde.rejectDrag();
return;
}
// Is this a valid node for dropping?
TreePath dropPath = TreeDragAndDropWidget.this.tree.getClosestPathForLocation(dtde
.getLocation().x, dtde.getLocation().y);
TreeNode currentDropNode = (TreeNode) dropPath
.getLastPathComponent();
if ((dropPath == null) || (currentDropNode == null)
|| currentDropNode.equals(this.lastDragOverNode)) {
return;
} else {
this.lastDragOverNode = currentDropNode;
}
Transferable transferable = this.getTransferable(dtde); // dtde.getTransferable();
boolean mayDropHere = false;
try {
// WARNING: getTransferable available only on JDK 1.5
TransferableTreeNode transferredNode = (TransferableTreeNode) transferable
.getTransferData(TransferableTreeNode
.getJavaJVMLocalObjectFlavor());
JTree sourceTree = transferredNode.getSourceTree();
MutableTreeNode sourceNode = transferredNode.getSourceNode();
if (TreeDragAndDropWidget.this.mayDropHere(sourceTree, sourceNode, dropPath)) {
TreeDragAndDropWidget.this.dropNode = (MutableTreeNode) dropPath
.getLastPathComponent();
if (!TreeDragAndDropWidget.this.tree.isExpanded(dropPath))
TreeDragAndDropWidget.this.tree.expandPath(dropPath);
mayDropHere = true;
} else {
TreeDragAndDropWidget.this.dropNode = null;
}
} catch (UnsupportedFlavorException ufe) {
// Oh, this is not a TransferableTreeNode, so maybe is a String,
// maybe?
try {
String sourceText = (String) transferable
.getTransferData(DataFlavor.stringFlavor);
if (TreeDragAndDropWidget.this.mayDropHere(sourceText, TreeDragAndDropWidget.this.tree, dropPath)) {
TreeDragAndDropWidget.this.dropNode = (MutableTreeNode) dropPath
.getLastPathComponent();
if (!TreeDragAndDropWidget.this.tree.isExpanded(dropPath))
TreeDragAndDropWidget.this.tree.expandPath(dropPath);
mayDropHere = true;
} else {
TreeDragAndDropWidget.this.dropNode = null;
}
} catch (Exception e) {
// Well, whatever, just discard
TreeDragAndDropWidget.this.dropNode = null;
}
} catch (Exception e) {
// IOException: Oh, there's a problem with serialization. Maybe
// a classloader issue? Well, ummm... just discard this and say
// no
// ClassCastException: Oh, user is transferring a JVM object but
// not a TransferableTreeNode, well, umm... just discard and say
// no
TreeDragAndDropWidget.this.dropNode = null;
}
TreeDragAndDropWidget.this.rendererProxy.setDropAllowed(mayDropHere);
TreeDragAndDropWidget.this.rendererProxy.setDropNode((TreeNode) dropPath
.getLastPathComponent());
TreeDragAndDropWidget.this.tree.repaint();
if (!mayDropHere) {
dtde.rejectDrag();
} else {
dtde.acceptDrag(dtde.getDropAction());
}
TreeDragAndDropWidget.this.tree.repaint();
}
public void dragEnter(DropTargetDragEvent dtde) {
this.dragOver(dtde);
// dtde.acceptDrag(DnDConstants.ACTION_COPY_OR_MOVE );
}
}
/**
* Invoked to decide if a given String can be dropped in the last path
* component of the given path.
*
* @param aSourceString
* the String being dragged.
* @param aPath
* the path to drop into.
* @return true to allow the drop operation, false otherwise.
*/
private boolean mayDropHere(String aSourceString, JTree aTargetTree,
TreePath aPath) {
return this.mayDropHere(aSourceString, aTargetTree, (TreeNode) aPath
.getLastPathComponent());
}
/**
* Invoked to decide if a given String can be dropped in the last path
* component of the given path.
*
* @param aSourceString
* the String being dragged.
* @param aPath
* the path to drop into.
* @return true to allow the drop operation, false otherwise.
*/
private boolean mayDropHere(String aSourceString, JTree aTargetTree,
TreeNode aNode) {
EventListener[] listeners = this.listeners
.getListeners(StringTreeDnDListener.class);
if ((listeners != null) && (listeners.length > 0)) {
try {
StringTreeDnDEvent event = new StringTreeDnDEvent(
aSourceString, aTargetTree, aNode);
for (int i = 0; i < listeners.length; i++) {
((StringTreeDnDListener) listeners[i]).mayDrop(event);
}
} catch (DnDVetoException exception) {
return false;
}
}
return true;
}
/**
* Invoked to decide if draggedNode can be dropped in the last path
* component of the given path.
*
* @param aSourceTree
* the source tree.
* @param aSourceNode
* the source node.
* @param aPath
* the path to drop into.
* @return true to allow the drop operation, false otherwise.
*/
private boolean mayDropHere(JTree aSourceTree, MutableTreeNode aSourceNode,
TreePath aPath) {
if (aPath == null)
return false;
return this.mayDropHere(aSourceTree, aSourceNode, (TreeNode) aPath
.getLastPathComponent());
}
/**
* Invoked to decide if draggedNode can be dropped into aNode.
*
* @param aSourceTree
* the source tree.
* @param aSourceNode
* the source node.
* @param aNode
* the node to drop into.
* @return true to allow the drop operation, false to avoid it.
*/
private boolean mayDropHere(JTree aSourceTree, MutableTreeNode aSourceNode,
TreeNode aNode) {
boolean mayDropHere = (aNode != aSourceNode)
&& (aNode instanceof MutableTreeNode)
&& ((aNode.getParent() == null) || (aNode.getParent() instanceof MutableTreeNode))
&& (this.tree.getModel() instanceof DefaultTreeModel)
&& !((this.tree == aSourceTree) && TreeDragAndDropWidget.isAncestorOf(aSourceNode, aNode));
if (mayDropHere) {
// Ask listeners
EventListener[] listeners = this.listeners
.getListeners(TreeTreeDnDListener.class);
if ((listeners != null) && (listeners.length > 0)) {
try {
TreeTreeDnDEvent event = new TreeTreeDnDEvent(aSourceTree,
aSourceNode, this.tree, aNode);
for (int i = 0; i < listeners.length; i++) {
((TreeTreeDnDListener) listeners[i]).mayDrop(event);
}
} catch (DnDVetoException exception) {
mayDropHere = false;
}
}
}
return mayDropHere;
}
/**
* See if aPossibleParent is ancestor of aNode
*/
private static boolean isAncestorOf(TreeNode aPossibleParent, TreeNode aNode) {
if ((aPossibleParent == null) || (aNode.getParent() == null))
return false;
else if (aNode.getParent() == aPossibleParent)
return true;
else
return TreeDragAndDropWidget.isAncestorOf(aPossibleParent, aNode.getParent());
}
private void resetDragAndDrop() {
this.dropNode = null;
this.rendererProxy.setDraggedNode(null);
this.rendererProxy.setDropAllowed(false);
this.rendererProxy.setDropNode(null);
this.tree.repaint();
}
}
