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diff --git a/libjava/classpath/javax/swing/undo/UndoableEditSupport.java b/libjava/classpath/javax/swing/undo/UndoableEditSupport.java
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+/* UndoableEditSupport.java --
+   Copyright (C) 2002, 2003, 2004, 2005, 2006,  Free Software Foundation, Inc.
+
+This file is part of GNU Classpath.
+
+GNU Classpath is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+GNU Classpath is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Classpath; see the file COPYING.  If not, write to the
+Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301 USA.
+
+Linking this library statically or dynamically with other modules is
+making a combined work based on this library.  Thus, the terms and
+conditions of the GNU General Public License cover the whole
+combination.
+
+As a special exception, the copyright holders of this library give you
+permission to link this library with independent modules to produce an
+executable, regardless of the license terms of these independent
+modules, and to copy and distribute the resulting executable under
+terms of your choice, provided that you also meet, for each linked
+independent module, the terms and conditions of the license of that
+module.  An independent module is a module which is not derived from
+or based on this library.  If you modify this library, you may extend
+this exception to your version of the library, but you are not
+obligated to do so.  If you do not wish to do so, delete this
+exception statement from your version. */
+
+
+package javax.swing.undo;
+
+import java.util.Iterator;
+import java.util.Vector;
+
+import javax.swing.event.UndoableEditEvent;
+import javax.swing.event.UndoableEditListener;
+
+/**
+ * A helper class for supporting {@link
+ * javax.swing.event.UndoableEditListener}.
+ *
+ * @author Andrew Selkirk (aselkirk@sympatico.ca)
+ * @author Sascha Brawer (brawer@dandelis.ch)
+ */
+public class UndoableEditSupport
+{
+  /**
+   * The number of times that {@link #beginUpdate()} has been called
+   * without a matching call to {@link #endUpdate()}.
+   */
+  protected int updateLevel;
+
+
+  /**
+   * compoundEdit
+   */
+  protected CompoundEdit compoundEdit;
+
+
+  /**
+   * The currently registered listeners.
+   */
+  protected Vector<UndoableEditListener> listeners =
+    new Vector<UndoableEditListener>();
+
+
+  /**
+   * The source of the broadcast UndoableEditEvents.
+   */
+  protected Object realSource;
+
+
+  /**
+   * Constructs a new helper for broadcasting UndoableEditEvents.  The
+   * events will indicate the newly constructed
+   * <code>UndoableEditSupport</code> instance as their source.
+   *
+   * @see #UndoableEditSupport(java.lang.Object)
+   */
+  public UndoableEditSupport()
+  {
+    realSource = this;
+  }
+
+
+  /**
+   * Constructs a new helper for broadcasting UndoableEditEvents.
+   *
+   * @param realSource the source of the UndoableEditEvents that will
+   * be broadcast by this helper. If <code>realSource</code> is
+   * <code>null</code>, the events will indicate the newly constructed
+   * <code>UndoableEditSupport</code> instance as their source.
+   */
+  public UndoableEditSupport(Object realSource)
+  {
+    if (realSource == null)
+      realSource = this;
+    this.realSource = realSource;
+  }
+
+
+  /**
+   * Returns a string representation of this object that may be useful
+   * for debugging.
+   */
+  public String toString()
+  {
+    // Note that often, this.realSource == this. Therefore, dumping
+    // realSource without additional checks may lead to infinite
+    // recursion. See Classpath bug #7119.
+    return super.toString() + " updateLevel: " + updateLevel
+      + " listeners: " + listeners + " compoundEdit: " + compoundEdit;
+  }
+
+
+  /**
+   * Registers a listener.
+   *
+   * @param val the listener to be added.
+   */
+  public synchronized void addUndoableEditListener(UndoableEditListener val)
+  {
+    listeners.add(val);
+  }
+
+
+  /**
+   * Unregisters a listener.
+   * @param val the listener to be removed.
+   */
+  public synchronized void removeUndoableEditListener(UndoableEditListener val)
+  {
+    listeners.removeElement(val);
+  }
+
+
+  /**
+   * Returns an array containing the currently registered listeners.
+   */
+  public synchronized UndoableEditListener[] getUndoableEditListeners()
+  {
+    UndoableEditListener[] result = new UndoableEditListener[listeners.size()];
+    return listeners.toArray(result);
+  }
+
+
+  /**
+   * Notifies all registered listeners that an {@link
+   * UndoableEditEvent} has occured.
+   *
+   * <p><b>Lack of Thread Safety:</b> It is <em>not</em> safe to call
+   * this method from concurrent threads, unless the call is protected
+   * by a synchronization on this <code>UndoableEditSupport</code>
+   * instance.
+   *
+   * @param edit the edit action to be posted.
+   */
+  protected void _postEdit(UndoableEdit edit)
+  {
+    UndoableEditEvent event;
+    Iterator<UndoableEditListener> iter;
+
+    // Do nothing if we have no listeners.
+    if (listeners.isEmpty())
+      return;
+
+    event = new UndoableEditEvent(realSource, edit);
+
+    // We clone the vector because this allows listeners to register
+    // or unregister listeners in their undoableEditHappened method.
+    // Otherwise, this would throw exceptions (in the case of
+    // Iterator, a java.util.ConcurrentModificationException; in the
+    // case of a direct loop over the Vector elements, some
+    // index-out-of-bounds exception).
+    iter = new Vector<UndoableEditListener>(listeners).iterator();
+    while (iter.hasNext())
+      iter.next().undoableEditHappened(event);
+  }
+
+
+  /**
+   * If {@link #beginUpdate} has been called (so that the current
+   * update level is greater than zero), adds the specified edit
+   * to {@link #compoundEdit}. Otherwise, notify listeners of the
+   * edit by calling {@link #_postEdit(UndoableEdit)}.
+   *
+   * <p><b>Thread Safety:</b> It is safe to call this method from any
+   * thread without external synchronization.
+   *
+   * @param edit the edit action to be posted.
+   */
+  public synchronized void postEdit(UndoableEdit edit)
+  {
+    if (compoundEdit != null)
+      compoundEdit.addEdit(edit);
+    else
+      _postEdit(edit);
+  }
+
+
+  /**
+   * Returns the current update level.
+   */
+  public int getUpdateLevel()
+  {
+    return updateLevel;
+  }
+
+
+  /**
+   * Starts a (possibly nested) update session. If the current update
+   * level is zero, {@link #compoundEdit} is set to the result of the
+   * {@link #createCompoundEdit} method. In any case, the update level
+   * is increased by one.
+   *
+   * <p><b>Thread Safety:</b> It is safe to call this method from any
+   * thread without external synchronization.
+   */
+  public synchronized void beginUpdate()
+  {
+    if (compoundEdit == null)
+      compoundEdit = createCompoundEdit();
+    ++updateLevel;
+  }
+
+
+  /**
+   * Creates a new instance of {@link CompoundEdit}. Called by {@link
+   * #beginUpdate}. If a subclass wants {@link #beginUpdate} to work
+   * on a specific {@link #compoundEdit}, it should override this
+   * method.
+   *
+   * @return a newly created instance of {@link CompoundEdit}.
+   */
+  protected CompoundEdit createCompoundEdit()
+  {
+    return new CompoundEdit();
+  }
+
+
+  /**
+   * Ends an update session. If the terminated session was the
+   * outermost session, {@link #compoundEdit} will receive an
+   * <code>end</code> message, and {@link #_postEdit} gets called in
+   * order to notify any listeners. Finally, the
+   * <code>compoundEdit</code> is discarded.
+   *
+   * <p><b>Thread Safety:</b> It is safe to call this method from any
+   * thread without external synchronization.
+   */
+  public synchronized void endUpdate()
+  {
+    if (updateLevel == 0)
+      throw new IllegalStateException();
+
+    if (--updateLevel > 0)
+      return;
+
+    compoundEdit.end();
+    _postEdit(compoundEdit);
+    compoundEdit = null;
+  }
+}