| /* |
| * Copyright 1997-2008 Sun Microsystems, Inc. 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. Sun designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| * CA 95054 USA or visit www.sun.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; |
| |
| /** |
| * <P>StateEdit is a general edit for objects that change state. |
| * Objects being edited must conform to the StateEditable interface.</P> |
| * |
| * <P>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.</P> |
| * |
| * A state edit is used as follows: |
| * <PRE> |
| * // 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(); |
| * </PRE> |
| * |
| * <P><EM>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!</EM></P> |
| * |
| * @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<Object,Object> preState; |
| |
| /** |
| * The state information after the edit |
| */ |
| protected Hashtable<Object,Object> postState; |
| |
| /** |
| * The undo/redo presentation name |
| */ |
| protected String undoRedoName; |
| |
| // |
| // Constructors |
| // |
| |
| /** |
| * Create and return a new StateEdit. |
| * |
| * @param anObject The object to watch for changing state |
| * |
| * @see StateEdit |
| */ |
| public StateEdit(StateEditable anObject) { |
| super(); |
| init (anObject,null); |
| } |
| |
| /** |
| * Create and return a new StateEdit with a presentation name. |
| * |
| * @param anObject The object to watch for changing state |
| * @param name The presentation name to be used for this edit |
| * |
| * @see StateEdit |
| */ |
| public StateEdit(StateEditable anObject, String name) { |
| super(); |
| init (anObject,name); |
| } |
| |
| protected void init (StateEditable anObject, String name) { |
| this.object = anObject; |
| this.preState = new Hashtable<Object, Object>(11); |
| this.object.storeState(this.preState); |
| this.postState = null; |
| this.undoRedoName = name; |
| } |
| |
| |
| // |
| // Operation |
| // |
| |
| |
| /** |
| * Gets the post-edit state of the StateEditable object and |
| * ends the edit. |
| */ |
| public void end() { |
| this.postState = new Hashtable<Object, Object>(11); |
| this.object.storeState(this.postState); |
| this.removeRedundantState(); |
| } |
| |
| /** |
| * Tells the edited object to apply the state prior to the edit |
| */ |
| public void undo() { |
| super.undo(); |
| this.object.restoreState(preState); |
| } |
| |
| /** |
| * Tells the edited object to apply the state after the edit |
| */ |
| public void redo() { |
| super.redo(); |
| this.object.restoreState(postState); |
| } |
| |
| /** |
| * Gets the presentation name for this edit |
| */ |
| public String getPresentationName() { |
| return this.undoRedoName; |
| } |
| |
| |
| // |
| // Internal support |
| // |
| |
| /** |
| * Remove redundant key/values in state hashtables. |
| */ |
| protected void removeRedundantState() { |
| Vector<Object> uselessKeys = new Vector<Object>(); |
| Enumeration myKeys = preState.keys(); |
| |
| // Locate redundant state |
| while (myKeys.hasMoreElements()) { |
| Object myKey = myKeys.nextElement(); |
| if (postState.containsKey(myKey) && |
| postState.get(myKey).equals(preState.get(myKey))) { |
| uselessKeys.addElement(myKey); |
| } |
| } |
| |
| // Remove redundant state |
| for (int i = uselessKeys.size()-1; i >= 0; i--) { |
| Object myKey = uselessKeys.elementAt(i); |
| preState.remove(myKey); |
| postState.remove(myKey); |
| } |
| } |
| |
| } // End of class StateEdit |