- /*
- * @(#)UndoableEditSupport.java 1.20 04/05/05
- *
- * Copyright 2004 Sun Microsystems, Inc. All rights reserved.
- * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
- */
-
- package javax.swing.undo;
-
- import javax.swing.event.*;
- import java.util.*;
-
- /**
- * A support class used for managing <code>UndoableEdit</code> listeners.
- *
- * @author Ray Ryan
- * @version 1.20 05/05/04
- */
- public class UndoableEditSupport {
- protected int updateLevel;
- protected CompoundEdit compoundEdit;
- protected Vector<UndoableEditListener> listeners;
- protected Object realSource;
-
- /**
- * Constructs an <code>UndoableEditSupport</code> object.
- */
- public UndoableEditSupport() {
- this(null);
- }
-
- /**
- * Constructs an <code>UndoableEditSupport</code> object.
- *
- * @param r an <code>Object</code>
- */
- public UndoableEditSupport(Object r) {
- realSource = r == null ? this : r;
- updateLevel = 0;
- compoundEdit = null;
- listeners = new Vector<UndoableEditListener>();
- }
-
- /**
- * Registers an <code>UndoableEditListener</code>.
- * The listener is notified whenever an edit occurs which can be undone.
- *
- * @param l an <code>UndoableEditListener</code> object
- * @see #removeUndoableEditListener
- */
- public synchronized void addUndoableEditListener(UndoableEditListener l) {
- listeners.addElement(l);
- }
-
- /**
- * Removes an <code>UndoableEditListener</code>.
- *
- * @param l the <code>UndoableEditListener</code> object to be removed
- * @see #addUndoableEditListener
- */
- public synchronized void removeUndoableEditListener(UndoableEditListener l)
- {
- listeners.removeElement(l);
- }
-
- /**
- * Returns an array of all the <code>UndoableEditListener</code>s added
- * to this UndoableEditSupport with addUndoableEditListener().
- *
- * @return all of the <code>UndoableEditListener</code>s added or an empty
- * array if no listeners have been added
- * @since 1.4
- */
- public synchronized UndoableEditListener[] getUndoableEditListeners() {
- return (UndoableEditListener[])(listeners.toArray(
- new UndoableEditListener[0]));
- }
-
- /**
- * Called only from <code>postEdit</code> and <code>endUpdate</code>. Calls
- * <code>undoableEditHappened</code> in all listeners. No synchronization
- * is performed here, since the two calling methods are synchronized.
- */
- protected void _postEdit(UndoableEdit e) {
- UndoableEditEvent ev = new UndoableEditEvent(realSource, e);
- Enumeration cursor = ((Vector)listeners.clone()).elements();
- while (cursor.hasMoreElements()) {
- ((UndoableEditListener)cursor.nextElement()).
- undoableEditHappened(ev);
- }
- }
-
- /**
- * DEADLOCK WARNING: Calling this method may call
- * <code>undoableEditHappened</code> in all listeners.
- * It is unwise to call this method from one of its listeners.
- */
- public synchronized void postEdit(UndoableEdit e) {
- if (updateLevel == 0) {
- _postEdit(e);
- } else {
- // PENDING(rjrjr) Throw an exception if this fails?
- compoundEdit.addEdit(e);
- }
- }
-
- /**
- * Returns the update level value.
- *
- * @return an integer representing the update level
- */
- public int getUpdateLevel() {
- return updateLevel;
- }
-
- /**
- *
- */
- public synchronized void beginUpdate() {
- if (updateLevel == 0) {
- compoundEdit = createCompoundEdit();
- }
- updateLevel++;
- }
-
- /**
- * Called only from <code>beginUpdate</code>.
- * Exposed here for subclasses' use.
- */
- protected CompoundEdit createCompoundEdit() {
- return new CompoundEdit();
- }
-
- /**
- * DEADLOCK WARNING: Calling this method may call
- * <code>undoableEditHappened</code> in all listeners.
- * It is unwise to call this method from one of its listeners.
- */
- public synchronized void endUpdate() {
- updateLevel--;
- if (updateLevel == 0) {
- compoundEdit.end();
- _postEdit(compoundEdit);
- compoundEdit = null;
- }
- }
-
- /**
- * Returns a string that displays and identifies this
- * object's properties.
- *
- * @return a <code>String</code> representation of this object
- */
- public String toString() {
- return super.toString() +
- " updateLevel: " + updateLevel +
- " listeners: " + listeners +
- " compoundEdit: " + compoundEdit;
- }
- }
-
-