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package test;
import java.awt.*;
import java.awt.datatransfer.*;
import java.io.*;
import java.util.*;
import javax.swing.*;
import javax.swing.table.*;
import javax.swing.tree.*;
/**
* <p>Title: </p>
*
* <p>Description: </p>
*
* <p>Copyright: Copyright (c) 2005</p>
*
* <p>Company: </p>
*
* @author not attributable
* @version 1.0
*/
class TreeTransfertHandler extends TransferHandler {
/** Last imported tree node.
*/
private DefaultMutableTreeNode importedNode = null;
/** Creates a new instance.
*/
public TreeTransfertHandler() {
}
/** {@inheritDoc}
* <BR>As of Java 1.4.x and 5.0 this method does not work properly (see bug <A HREF="http://developer.java.sun.com/developer/bugParade/bugs/4816922.html">#4816922</A> at Sun's web site).
*/
@Override public Icon getVisualRepresentation(Transferable t) {
return super.getVisualRepresentation(t);
}
/** {@inheritDoc}
*/
@Override protected Transferable createTransferable(JComponent component) {
String entity = exportEntity(component);
// We could use a better transferable that could handle several dataflavors (text+image+treePath to node+....) at once.
// So far this one is good for this TransferHandler and to ANY (including non-Java) app that can receive the STRING_FLAVOR.
return new StringSelection(entity);
}
/** {@inheritDoc}
*/
@Override protected void exportDone(JComponent c, Transferable data, int action) {
cleanup(c, action == MOVE);
}
/////////////////////////////////
// TransferHelper overloading. //
/////////////////////////////////
/** {@inheritDoc}
*/
@Override public int getSourceActions(JComponent component) {
JTree tree = (JTree) component;
Object lastPathComponent = tree.getSelectionPath().getLastPathComponent();
if (lastPathComponent instanceof DefaultMutableTreeNode) {
DefaultMutableTreeNode node = (DefaultMutableTreeNode) lastPathComponent;
Object obj = node.getUserObject();
if (obj instanceof String) {
return COPY_OR_MOVE;
}
}
return NONE;
}
/** {@inheritDoc}
*/
@Override public boolean canImport(JComponent component, DataFlavor[] flavors) {
for (DataFlavor f : flavors) {
// We can only import STRING_FLAVOR (plain text) so far.
// We may add additional data flavors here in the future.
if (DataFlavor.stringFlavor.equals(f)) {
return true;
}
}
return false;
}
/** {@inheritDoc}
*/
@Override public boolean importData(JComponent component, Transferable t) {
if (canImport(component, t.getTransferDataFlavors())) {
try {
// Remember as of now, we can only deal with STRING_FLAVOR.
String text = (String) t.getTransferData(DataFlavor.stringFlavor);
// We cheat, normally we should look into the tree for the proper node.
// We could export the tree path to the node as a custom data flavor.
// We have to test this when doing DnD with 2 different trees.
return importEntity((JTree) component, importedNode);
}
catch (UnsupportedFlavorException ufe) {
System.err.println(ufe);
}
catch (IOException ioe) {
System.err.println(ioe);
}
}
return false;
}
/////////////////////////
// Convenient methods. //
/////////////////////////
/** Exports an entity from a component.
* @param component The source component.
* @return The entity to be exported.
*/
public String exportEntity(JComponent component) {
JTree tree = (JTree) component;
Object lastPathComponent = tree.getSelectionPath().getLastPathComponent();
if (lastPathComponent instanceof DefaultMutableTreeNode) {
DefaultMutableTreeNode node = (DefaultMutableTreeNode) lastPathComponent;
Object obj = node.getUserObject();
if (obj instanceof String) {
importedNode = node;
return (String) obj;
}
}
return null;
}
/** Imports a string to a component.
* @param component The target component.
* @param importedNode The node to import.
* @return <code>True</code> if import was successfull, <code>false</code> otherwise.
*/
public boolean importEntity(JComponent component, DefaultMutableTreeNode importedNode) {
JTree tree = (JTree) component;
Object lastPathComponent = tree.getSelectionPath().getLastPathComponent();
if (lastPathComponent instanceof DefaultMutableTreeNode) {
DefaultMutableTreeNode targetNode = (DefaultMutableTreeNode) lastPathComponent;
TreeNode rootNode = targetNode.getRoot();
Enumeration ancestorEnumeration = targetNode.pathFromAncestorEnumeration(rootNode);
// Verify we do not try to move the node to one of its sub-nodes.
while (ancestorEnumeration.hasMoreElements()) {
DefaultMutableTreeNode ancestorNode = (DefaultMutableTreeNode) ancestorEnumeration.nextElement();
if (ancestorNode.equals(importedNode)) {
System.err.println("Cannot import " + importedNode + " because " + ancestorNode + " is part of the path from " + targetNode + " to " + rootNode);
return false;
}
}
DefaultTreeModel model = (DefaultTreeModel) tree.getModel();
// Create a copy of the node structure.
DefaultMutableTreeNode nodeCopy = duplicateNodeStructure(importedNode);
model.insertNodeInto(nodeCopy, targetNode, 0);
return true;
}
return false;
}
/** Cleanup after export.
* @param component The source component.
* @param remove <CODE>True</CODE> if the selection should be removed from the component; <CODE>false</CODE> otherwise.
*/
protected void cleanup(JComponent component, boolean remove) {
JTree tree = (JTree) component;
// Remove string node from parent node.
if (remove) {
DefaultTreeModel model = (DefaultTreeModel) tree.getModel();
model.removeNodeFromParent(importedNode);
}
// Clean references.
importedNode = null;
}
/** Duplicate a node structure.
* @param sourceNode The source node.
* @return A copy of the given node and all its sub-nodes.
*/
private DefaultMutableTreeNode duplicateNodeStructure(DefaultMutableTreeNode sourceNode) {
if (sourceNode == null) {
return null;
}
DefaultMutableTreeNode result = new DefaultMutableTreeNode(sourceNode.getUserObject());
Enumeration childrenEnumeration = sourceNode.children();
while (childrenEnumeration.hasMoreElements()) {
DefaultMutableTreeNode child = duplicateNodeStructure((DefaultMutableTreeNode) childrenEnumeration.nextElement());
result.add(child);
}
return result;
}
} |
