001 /* UndoableEdit.java --
002 Copyright (C) 2002, 2006, Free Software Foundation, Inc.
003
004 This file is part of GNU Classpath.
005
006 GNU Classpath is free software; you can redistribute it and/or modify
007 it under the terms of the GNU General Public License as published by
008 the Free Software Foundation; either version 2, or (at your option)
009 any later version.
010
011 GNU Classpath is distributed in the hope that it will be useful, but
012 WITHOUT ANY WARRANTY; without even the implied warranty of
013 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
014 General Public License for more details.
015
016 You should have received a copy of the GNU General Public License
017 along with GNU Classpath; see the file COPYING. If not, write to the
018 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
019 02110-1301 USA.
020
021 Linking this library statically or dynamically with other modules is
022 making a combined work based on this library. Thus, the terms and
023 conditions of the GNU General Public License cover the whole
024 combination.
025
026 As a special exception, the copyright holders of this library give you
027 permission to link this library with independent modules to produce an
028 executable, regardless of the license terms of these independent
029 modules, and to copy and distribute the resulting executable under
030 terms of your choice, provided that you also meet, for each linked
031 independent module, the terms and conditions of the license of that
032 module. An independent module is a module which is not derived from
033 or based on this library. If you modify this library, you may extend
034 this exception to your version of the library, but you are not
035 obligated to do so. If you do not wish to do so, delete this
036 exception statement from your version. */
037
038 package javax.swing.undo;
039
040 /**
041 * An editing operation that supports undo/redoability.
042 *
043 * @author Andrew Selkirk
044 */
045 public interface UndoableEdit
046 {
047
048 /**
049 * Incorporates another editing action into this one, thus forming a
050 * combined action.
051 *
052 * @param edit the editing action to be incorporated.
053 *
054 * @return <code>true</code> if the edit was combined successfully, and
055 * <code>false</code> if it could not be combined.
056 */
057 boolean addEdit(UndoableEdit edit);
058
059 /**
060 * Determines whether it would be possible to redo this editing
061 * action.
062 *
063 * @return <code>true</code> to indicate that this action can be
064 * redone, <code>false</code> otherwise.
065 *
066 * @see #redo()
067 * @see #canUndo()
068 */
069 boolean canRedo();
070
071 /**
072 * Determines whether it would be possible to undo this editing
073 * action.
074 *
075 * @return <code>true</code> to indicate that this action can be
076 * undone, <code>false</code> otherwise.
077 *
078 * @see #undo()
079 * @see #canRedo()
080 */
081 boolean canUndo();
082
083 /**
084 * Informs this edit action that it will no longer be used. Some
085 * actions might use this information to release resources, for
086 * example open files. Called by {@link UndoManager} before this
087 * action is removed from the edit queue.
088 */
089 void die();
090
091 /**
092 * Returns a human-readable, localized name that describes this
093 * editing action and can be displayed to the user.
094 *
095 * @return The presentation name.
096 */
097 String getPresentationName();
098
099 /**
100 * Returns the redo presentation name.
101 *
102 * @return The redo presentation name.
103 */
104 String getRedoPresentationName();
105
106 /**
107 * Returns the undo presentation name.
108 *
109 * @return The undo presentation name.
110 */
111 String getUndoPresentationName();
112
113 /**
114 * Determines whether this editing action is significant enough for
115 * being seperately undoable by the user. A typical significant
116 * action would be the resizing of an object. However, changing the
117 * selection in a text document would usually not be considered
118 * significant.
119 *
120 * @return <code>true</code> to indicate that the action is
121 * significant enough for being separately undoable, or
122 * <code>false</code> otherwise.
123 */
124 boolean isSignificant();
125
126 /**
127 * Redoes this editing action.
128 *
129 * @throws CannotRedoException if the edit cannot be undone.
130 *
131 * @see #canRedo()
132 * @see #undo()
133 */
134 void redo() throws CannotRedoException;
135
136 /**
137 * Incorporates another editing action into this one, thus forming a
138 * combined action that replaces the argument action.
139 *
140 * @param edit the editing action to be replaced.
141 *
142 * @return <code>true</code> if the edit is successfully replaced, and
143 * <code>false</code> otherwise.
144 */
145 boolean replaceEdit(UndoableEdit edit);
146
147 /**
148 * Undoes this editing action.
149 *
150 * @throws CannotUndoException if the edit cannot be undone.
151 *
152 * @see #canUndo()
153 * @see #redo()
154 */
155 void undo() throws CannotUndoException;
156
157 }