libjava/classpath/javax/swing/undo/UndoableEdit.java

   1 /* UndoableEdit.java --
   2    Copyright (C) 2002, 2006, Free Software Foundation, Inc.
   3
   4 This file is part of GNU Classpath.
   5
   6 GNU Classpath is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU Classpath is distributed in the hope that it will be useful, but
  12 WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Classpath; see the file COPYING.  If not, write to the
  18 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19 02110-1301 USA.
  20
  21 Linking this library statically or dynamically with other modules is
  22 making a combined work based on this library.  Thus, the terms and
  23 conditions of the GNU General Public License cover the whole
  24 combination.
  25
  26 As a special exception, the copyright holders of this library give you
  27 permission to link this library with independent modules to produce an
  28 executable, regardless of the license terms of these independent
  29 modules, and to copy and distribute the resulting executable under
  30 terms of your choice, provided that you also meet, for each linked
  31 independent module, the terms and conditions of the license of that
  32 module.  An independent module is a module which is not derived from
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  35 obligated to do so.  If you do not wish to do so, delete this
  36 exception statement from your version. */
  37
  38 package javax.swing.undo;
  39
  40 /**
  41  * An editing operation that supports undo/redoability.
  42  *
  43  * @author Andrew Selkirk
  44  */
  45 public interface UndoableEdit
  46 {
  47
  48   /**
  49    * Incorporates another editing action into this one, thus forming a
  50    * combined action.
  51    *
  52    * @param edit the editing action to be incorporated.
  53    *
  54    * @return <code>true</code> if the edit was combined successfully, and
  55    *         <code>false</code> if it could not be combined.
  56    */
  57   boolean addEdit(UndoableEdit edit);
  58
  59   /**
  60    * Determines whether it would be possible to redo this editing
  61    * action.
  62    *
  63    * @return <code>true</code> to indicate that this action can be
  64    * redone, <code>false</code> otherwise.
  65    *
  66    * @see #redo()
  67    * @see #canUndo()
  68    */
  69   boolean canRedo();
  70
  71   /**
  72    * Determines whether it would be possible to undo this editing
  73    * action.
  74    *
  75    * @return <code>true</code> to indicate that this action can be
  76    * undone, <code>false</code> otherwise.
  77    *
  78    * @see #undo()
  79    * @see #canRedo()
  80    */
  81   boolean canUndo();
  82
  83   /**
  84    * Informs this edit action that it will no longer be used. Some
  85    * actions might use this information to release resources, for
  86    * example open files.  Called by {@link UndoManager} before this
  87    * action is removed from the edit queue.
  88    */
  89   void die();
  90
  91   /**
  92    * Returns a human-readable, localized name that describes this
  93    * editing action and can be displayed to the user.
  94    *
  95    * @return The presentation name.
  96    */
  97   String getPresentationName();
  98
  99   /**
 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 }