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Java > Open Source Codes > org > netbeans > api > java > source > transform > UndoEntry


1 /*
2  * The contents of this file are subject to the terms of the Common Development
3  * and Distribution License (the License). You may not use this file except in
4  * compliance with the License.
5  *
6  * You can obtain a copy of the License at http://www.netbeans.org/cddl.html
7  * or http://www.netbeans.org/cddl.txt.
8  *
9  * When distributing Covered Code, include this CDDL Header Notice in each file
10  * and include the License file at http://www.netbeans.org/cddl.txt.
11  * If applicable, add the following below the CDDL Header, with the fields
12  * enclosed by brackets [] replaced by your own identifying information:
13  * "Portions Copyrighted [year] [name of copyright owner]"
14  *
15  * The Original Software is NetBeans. The Initial Developer of the Original
16  * Software is Sun Microsystems, Inc. Portions Copyright 1997-2006 Sun
17  * Microsystems, Inc. All Rights Reserved.
18  */
19
20 package org.netbeans.api.java.source.transform;
21
22 /**
23  * Base class for undo list entries. Undo actions are defined by subclassing
24  * this class (usually in an anonymous inner class) and defining undo() and
25  * redo(), and possibly other methods.
26  */
27 public abstract class UndoEntry {
28     public UndoEntry prev, next;
29     
30     protected boolean endCommand;
31     
32     public void addAfter(UndoEntry e) {
33     if(e==null) return;
34     e.next = this;
35     this.prev = e;
36     }
37     
38     /** Define the action(s) to execute during an undo. */
39     public abstract void undo();
40     
41     /** Define the action(s) to execute during a redo. */
42     public abstract void redo();
43
44     /** Returns a previous version of this object, or null if none exists. */
45     public <T> T getOld(T o) {
46     return null; // subclasses may do more
47 }
48
49     /** Is this the last entry in the todo list? */
50     public boolean isEndCommand() {
51     return endCommand;
52     }
53     
54     public void setEndCommand(boolean b) {
55     endCommand = b;
56     }
57 }
58
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