/* * Copyright (c) 1997, 2008, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code 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 * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package javax.swing.undo; import java.util.Enumeration; import java.util.Hashtable; import java.util.Vector; /** *
StateEdit is a general edit for objects that change state. * Objects being edited must conform to the StateEditable interface.
* *This edit class works by asking an object to store it's state in * Hashtables before and after editing occurs. Upon undo or redo the * object is told to restore it's state from these Hashtables.
* * A state edit is used as follows: ** // Create the edit during the "before" state of the object * StateEdit newEdit = new StateEdit(myObject); * // Modify the object * myObject.someStateModifyingMethod(); * // "end" the edit when you are done modifying the object * newEdit.end(); ** *
Note that when a StateEdit ends, it removes redundant state from * the Hashtables - A state Hashtable is not guaranteed to contain all * keys/values placed into it when the state is stored!
* * @see StateEditable * * @author Ray Ryan */ public class StateEdit extends AbstractUndoableEdit { protected static final String RCSID = "$Id: StateEdit.java,v 1.6 1997/10/01 20:05:51 sandipc Exp $"; // // Attributes // /** * The object being edited */ protected StateEditable object; /** * The state information prior to the edit */ protected Hashtable