Undo / Redo Feature in Swing

Question

Hi all,
Iam working on swing project which uses Undo/Redo feature for drag and drop figure and delete,cut,copy,paste and all the feature which ever want to use, and iam using multiple internal frames so the feature Undo/Redo should be specific to perticular internal frame.
Is any buddy already done such a kind of thing then pls help me, or if it's possible then pls send the code also.
Regards
Laxmikant

Answer 1

Hi,
you would have to create an UndoableEditListener for each object, undo/redo shall be perfomed. The listener then is connected to an instance of UndoManager to do the actual handling:  /** Listener for edits on a document. */
  private UndoableEditListener undoHandler = new UndoHandler();
  /** UndoManager that we add edits to. */
  private UndoManager undo = new UndoManager();
  /** inner class for handling undoable edit events */
  public class UndoHandler implements UndoableEditListener {
     * Messaged when the Document has created an edit, the edit is
     * added to <code>undo</code>, an instance of UndoManager.
    public void undoableEditHappened(UndoableEditEvent e) {
      undo.addEdit(e.getEdit());
  } This now can be registered with let's say a Document like thiseditor.getDocument().addUndoableEditListener(undoHandler); (editor is an instance of JEditorPane containing the document).
Once you have this, you only need actions to perform undo or redo by calling the respective method of your instance of UndoManager undo() and redo().
Hope that helps
Ulrich