5 Replies Latest reply on May 23, 2002 7:17 PM by 807582

Undo two or more actions at once

807582 May 23, 2002 4:30 PM

I have seen this question asked before without an answer and I have asked it with the title " HTMLDocument setInnerHTML or setOuterHTML and Undo", but without an answer as well.

I a have a few actions that use the setInnerHTML() and setOuterHTML() which actually perform an insert and then a remove element. This issue is not specific to the HTMLDocment, but to the use of an UndoManager.

How do I manipulate the data to return to its state prior to the end result of an action that is made up of more than one undoable edits? Basically, how would I group two, or possibly more, UndoableEdits as one UndoableEdit?

Although I am continueing to work on other aspects of my code, I am eventually going to be held up with this issue if I don't find a resolution.

1. Re: Undo two or more actions at once

807582 May 23, 2002 4:35 PM (in response to 807582)

In your undo method, just call undo twice, or whatever you need.
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2. Re: Undo two or more actions at once

807582 May 23, 2002 4:42 PM (in response to 807582)

Actually, not all of the actions use multiple undoable edits, i.e. bold, italic, pasting, cutting, etc. Perhaps there is a way to flag undoable edits as part of a sequence. Has anyone solve this issue before?

Thank you inadvace for your assistance.
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3. Re: Undo two or more actions at once

807582 May 23, 2002 4:42 PM (in response to 807582)

UndoableEdit.addEdit(anEdit) does what you want
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4. Re: Undo two or more actions at once

camickr May 23, 2002 6:20 PM (in response to 807582)

Here is a sample program that shows the concept of using CompoundEdits. It does not address how to programmatically start/stop a compound edit. Hope its of some help.

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.text.*;
import javax.swing.event.*;
import javax.swing.undo.*;

public class TestCompoundEdit extends JFrame
{
     private MyUndoableEditListener myUndoableEditListener;
     private UndoManager undoManager;
     private CompoundEdit compoundEdit;
     private boolean compounding;
     private JTextPane textPane;

public TestCompoundEdit()
{
          undoManager = new UndoManager();
          myUndoableEditListener = new MyUndoableEditListener();

JPanel panel = new JPanel();
panel.setLayout( new BorderLayout() );
     setContentPane( panel );

          textPane = new JTextPane();
          textPane.setPreferredSize( new Dimension(200, 200) );
          textPane.getDocument().addUndoableEditListener( myUndoableEditListener );
          panel.add( textPane, BorderLayout.CENTER );

          JPanel buttons = new JPanel();
          panel.add(buttons, BorderLayout.SOUTH);

          final JButton start = new JButton( "Start Compound Edit" );
          start.addActionListener( new ActionListener()
          {
               public void actionPerformed(ActionEvent e)
               {

                    if (isCompoundEdit())
                    {
                    compoundEdit.end();
                    undoManager.addEdit( compoundEdit );
                    setCompoundEdit( false );
                    start.setText( "Start Compound Edit" );
               }
                    else
                    {
                         compoundEdit = new CompoundEdit();
                         setCompoundEdit( true );
                    start.setText( "Stop Compound Edit" );
                    }

                    textPane.requestFocus();
               }
          });
          buttons.add( start );

          JButton undo = new JButton( "Undo" );
          undo.addActionListener( new ActionListener()
          {
               public void actionPerformed(ActionEvent e)
               {
               try
               {
                    undoManager.undo();
                         textPane.requestFocus();
               }
               catch (CannotUndoException ex)
               {
                    System.out.println("Unable to undo: " + ex);
               }
               }
          });
          buttons.add( undo );

          JButton redo = new JButton( "Redo" );
          redo.addActionListener( new ActionListener()
          {
               public void actionPerformed(ActionEvent e)
               {
               try
               {
                    undoManager.redo();
                         textPane.requestFocus();
               }
               catch (CannotRedoException ex)
               {
                    System.out.println("Unable to redo: " + ex);
               }
               }
          });
          buttons.add( redo );
     }

     public void setCompoundEdit(boolean value)
     {
          compounding = value;
     }

     public boolean isCompoundEdit()
     {
          return compounding;
     }

     class MyUndoableEditListener implements UndoableEditListener
     {
          public void undoableEditHappened(UndoableEditEvent e)
          {
               if (isCompoundEdit())
                    compoundEdit.addEdit(e.getEdit());
               else
               {
                    undoManager.addEdit(e.getEdit());
               }
          }
     }
public static void main(String[] args)
{
TestCompoundEdit frame = new TestCompoundEdit();
frame.setDefaultCloseOperation( EXIT_ON_CLOSE );
frame.pack();
frame.setVisible(true);
}
}
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5. Re: Undo two or more actions at once

807582 May 23, 2002 7:17 PM (in response to 807582)

Thanks for the lead. I researched it a little and coded the below. It works so far. Thanks for the help.

public class ExtendedHTMLDocument extends HTMLDocument {

     private boolean undoableSequence = false;
     private javax.swing.undo.CompoundEdit compoundEdit  = null;

     protected boolean isUndoableSequence() {
          return undoableSequence;
     }
     protected void startUndoableSequence() {
          endUndoableSequence();
          undoableSequence = true;
     }
     protected void endUndoableSequence() {
          if (compoundEdit != null && compoundEdit.isInProgress()) {
               compoundEdit.end();
          }
          compoundEdit = null;
          undoableSequence = false;
     }
     protected javax.swing.undo.CompoundEdit getUndoableSequence() {
          if (compoundEdit == null) {
               compoundEdit = new javax.swing.undo.CompoundEdit();
               super.fireUndoableEditUpdate(new UndoableEditEvent(this, compoundEdit));
          }
          return compoundEdit;
     }
     protected void fireUndoableEditUpdate(UndoableEditEvent _event) {
          if (isUndoableSequence()) {
               getUndoableSequence().addEdit(_event.getEdit());
          }
          else {
               super.fireUndoableEditUpdate(_event);
          }
     }
     public void setInnerHTML(Element _element, String _htmlText) throws BadLocationException, java.io.IOException {
          startUndoableSequence();
          super.setInnerHTML(_element, _htmlText);
          endUndoableSequence();
     }
     public void setOuterHTML(Element _element, String _htmlText) throws BadLocationException, java.io.IOException {
          startUndoableSequence();
          super.setOuterHTML(_element, _htmlText);
          endUndoableSequence();
     }
}

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