001    package nl.cwi.sen1.gui.plugin.editor;
002    
003    import javax.swing.event.DocumentEvent;
004    import javax.swing.text.AbstractDocument;
005    import javax.swing.undo.UndoManager;
006    import javax.swing.undo.UndoableEdit;
007    
008    public class EditorUndoManager extends UndoManager {
009        public synchronized boolean addEdit(UndoableEdit anEdit) {
010            if (anEdit instanceof AbstractDocument.DefaultDocumentEvent) {
011                AbstractDocument.DefaultDocumentEvent de = (AbstractDocument.DefaultDocumentEvent) anEdit;
012                if (de.getType() == DocumentEvent.EventType.CHANGE) {
013                    return false;
014                }
015            }
016            return super.addEdit(anEdit);
017        }
018    }