UndoActionHandler


1   /*******************************************************************************
2    * Copyright (c) 2005, 2006 IBM Corporation and others.
3    * All rights reserved. This program and the accompanying materials
4    * are made available under the terms of the Eclipse Public License v1.0
5    * which accompanies this distribution, and is available at
6    * http://www.eclipse.org/legal/epl-v10.html
7    *
8    * Contributors:
9    *     IBM Corporation - initial API and implementation
10   *******************************************************************************/
11  package org.eclipse.ui.operations;
12  
13  import org.eclipse.core.commands.ExecutionException;
14  import org.eclipse.core.commands.operations.IUndoContext;
15  import org.eclipse.core.commands.operations.IUndoableOperation;
16  import org.eclipse.core.runtime.IProgressMonitor;
17  import org.eclipse.core.runtime.IStatus;
18  import org.eclipse.ui.ISharedImages;
19  import org.eclipse.ui.IWorkbenchPartSite;
20  import org.eclipse.ui.PlatformUI;
21  import org.eclipse.ui.internal.WorkbenchMessages;
22  
23  
24  /**
25   * <p>
26   * UndoActionHandler provides common behavior for performing an undo, as
27   * well as labelling and enabling the undo menu item.  This class may be
28   * instantiated by clients.
29   * </p>
30   * 
31   * @since 3.1
32   */
33  public final class UndoActionHandler extends OperationHistoryActionHandler {
34  
35      /**
36       * Construct an action handler that handles the labelling and enabling of
37       * the undo action for the specified undo context.
38       * 
39       * @param site 
40       *            the workbench part site that created the action.
41       * @param context 
42       *            the undo context to be used for the undo
43       */
44      public UndoActionHandler(IWorkbenchPartSite site, IUndoContext context) {
45          super(site, context);
46          setImageDescriptor(PlatformUI.getWorkbench().getSharedImages()
47                  .getImageDescriptor(ISharedImages.IMG_TOOL_UNDO));
48          setDisabledImageDescriptor(PlatformUI.getWorkbench().getSharedImages()
49                  .getImageDescriptor(ISharedImages.IMG_TOOL_UNDO_DISABLED));
50      }
51  
52      void flush() {
53          getHistory().dispose(getUndoContext(), true, false, false);
54      }
55  
56      String   getCommandString() {
57          return WorkbenchMessages.Operations_undoCommand;
58      }
59      
60      String   getTooltipString() {
61          return WorkbenchMessages.Operations_undoTooltipCommand;
62      }
63      
64      String   getSimpleCommandString() {
65          return WorkbenchMessages.Workbench_undo;
66      }
67      
68      String   getSimpleTooltipString() {
69          return WorkbenchMessages.Workbench_undoToolTip;     
70      }
71  
72      IUndoableOperation getOperation() {
73          return getHistory().getUndoOperation(getUndoContext());
74  
75      }
76  
77      IStatus runCommand(IProgressMonitor pm) throws ExecutionException  {
78          return getHistory().undo(getUndoContext(), pm, this);
79      }
80  
81      boolean shouldBeEnabled() {
82          return getHistory().canUndo(getUndoContext());
83      }
84  }
85
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