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 }