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Added dwt-addons in original directory structure of eclipse.org
author Frank Benoit <benoit@tionex.de>
date Sat, 14 Mar 2009 18:23:29 +0100
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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 * Port to the D programming language:
11 * Frank Benoit <benoit@tionex.de>
12 *******************************************************************************/
13 module org.eclipse.core.commands.operations.IOperationHistory;
14
15 import org.eclipse.core.commands.ExecutionException;
16 import org.eclipse.core.internal.commands.operations.GlobalUndoContext;
17 import org.eclipse.core.runtime.IAdaptable;
18 import org.eclipse.core.runtime.IProgressMonitor;
19 import org.eclipse.core.runtime.IStatus;
20
21 import org.eclipse.core.commands.operations.IUndoContext;
22 import org.eclipse.core.commands.operations.IUndoableOperation;
23 import org.eclipse.core.commands.operations.IOperationApprover;
24 import org.eclipse.core.commands.operations.IOperationApprover2;
25 import org.eclipse.core.commands.operations.IOperationHistoryListener;
26 import org.eclipse.core.commands.operations.ICompositeOperation;
27 import org.eclipse.core.commands.operations.OperationStatus;
28
29 import java.lang.all;
30
31 static this(){
32 IOperationHistory.GLOBAL_UNDO_CONTEXT = new GlobalUndoContext();
33 IOperationHistory.NOTHING_TO_REDO_STATUS = new OperationStatus(
34 IStatus.INFO, OperationStatus.DEFAULT_PLUGIN_ID,
35 OperationStatus.NOTHING_TO_REDO, "No operation to redo", null); //$NON-NLS-1$
36 IOperationHistory.NOTHING_TO_UNDO_STATUS = new OperationStatus(
37 IStatus.INFO, OperationStatus.DEFAULT_PLUGIN_ID,
38 OperationStatus.NOTHING_TO_UNDO, "No operation to undo", null); //$NON-NLS-1$
39 IOperationHistory.OPERATION_INVALID_STATUS = new OperationStatus(
40 IStatus.ERROR, OperationStatus.DEFAULT_PLUGIN_ID,
41 OperationStatus.OPERATION_INVALID, "Operation is not valid", null); //$NON-NLS-1$
42 }
43
44 /**
45 * <p>
46 * IOperationHistory tracks a history of operations that can be undone or
47 * redone. Operations are added to the history once they have been initially
48 * executed. Clients may choose whether to have the operations history perform
49 * the initial execution or to simply add an already-executed operation to the
50 * history.
51 * </p>
52 * <p>
53 * Once operations are added to the history, the methods
54 * {@link #canRedo(IUndoContext)} and {@link #canUndo(IUndoContext)} are used to
55 * determine whether there is an operation available for undo and redo in a
56 * given undo context. The context-based protocol implies that there is only one
57 * operation that can be undone or redone at a given time in a given context.
58 * This is typical of a linear undo model, when only the most recently executed
59 * operation is available for undo. When this protocol is used, a linear model
60 * is enforced by the history.
61 * </p>
62 * <p>
63 * It is up to clients to determine how to maintain a history that is invalid or
64 * stale. For example, when the most recent operation for a context cannot be
65 * performed, clients may wish to dispose the history for that context.
66 * </p>
67 * <p>
68 * Additional protocol allows direct undo and redo of a specified operation,
69 * regardless of its position in the history. When a more flexible undo model is
70 * supported, these methods can be implemented to undo and redo directly
71 * specified operations. If an implementer of IOperationHistory does not allow
72 * direct undo and redo, these methods can return a status indicating that it is
73 * not allowed.
74 * </p>
75 * <p>
76 * Listeners ({@link IOperationHistoryListener}) can listen for notifications
77 * about changes in the history (operations added or removed), and for
78 * notification before and after any operation is executed, undone or redone.
79 * Notification of operation execution only occurs when clients direct the
80 * history to execute the operation. If the operation is added after it is
81 * executed, there can be no notification of its execution.
82 * </p>
83 * <p>
84 * {@link IOperationApprover} defines an interface for approving an undo or redo
85 * before it occurs. This is useful for injecting policy-decisions into the undo
86 * model - whether direct undo and redo are supported, or warning the user about
87 * certain kinds of operations. It can also be used when clients maintain state
88 * related to an operation and need to determine whether an undo or redo will
89 * cause any conflicts with their local state.
90 * </p>
91 *
92 * @since 3.1
93 */
94 public interface IOperationHistory {
95
96 /**
97 * An operation is to be opened or closed for execution. (value is 1).
98 */
99 public static const int EXECUTE = 1;
100
101 /**
102 * An operation is to be opened for undo. (value is 2).
103 */
104 public static const int UNDO = 2;
105
106 /**
107 * An operation is to be opened for redo. (value is 3).
108 */
109 public static const int REDO = 3;
110
111 /**
112 * An undo context that can be used to refer to the global undo history.
113 * This context is not intended to be assigned to operations. Instead, it is
114 * used for querying the history or performing an undo or redo on the entire
115 * history, regardless of each operation's undo contexts.
116 */
117 public static /+const+/ IUndoContext GLOBAL_UNDO_CONTEXT;
118
119 /**
120 * An operation info status describing the condition that there is no
121 * available operation for redo.
122 */
123 public static /+const+/ IStatus NOTHING_TO_REDO_STATUS; //$NON-NLS-1$
124
125 /**
126 * An operation info status describing the condition that there is no
127 * available operation for undo.
128 */
129 public static /+const+/ IStatus NOTHING_TO_UNDO_STATUS; //$NON-NLS-1$
130
131 /**
132 * An operation error status describing the condition that the operation
133 * available for execution, undo or redo is not in a valid state for the
134 * action to be performed.
135 */
136 public static /+const+/ IStatus OPERATION_INVALID_STATUS; //$NON-NLS-1$
137
138 /**
139 * <p>
140 * Add the specified operation to the history without executing it. The
141 * operation should have already been executed by the time it is added to
142 * the history. Listeners will be notified that the operation was added to
143 * the history (<code>OPERATION_ADDED</code>).
144 * </p>
145 *
146 * @param operation
147 * the operation to be added to the history
148 */
149 void add(IUndoableOperation operation);
150
151 /**
152 * <p>
153 * Add the specified approver to the list of operation approvers consulted
154 * by the operation history before an undo or redo is attempted.
155 * </p>
156 *
157 * @param approver
158 * the IOperationApprover to be added as an approver.the instance
159 * to remove. Must not be <code>null</code>. If an attempt is
160 * made to register an instance which is already registered with
161 * this instance, this method has no effect.
162 *
163 * @see org.eclipse.core.commands.operations.IOperationApprover
164 */
165 void addOperationApprover(IOperationApprover approver);
166
167 /**
168 * <p>
169 * Add the specified listener to the list of operation history listeners
170 * that are notified about changes in the history or operations that are
171 * executed, undone, or redone.
172 * </p>
173 *
174 * @param listener
175 * the IOperationHistoryListener to be added as a listener. Must
176 * not be <code>null</code>. If an attempt is made to register
177 * an instance which is already registered with this instance,
178 * this method has no effect.
179 *
180 * @see org.eclipse.core.commands.operations.IOperationHistoryListener
181 * @see org.eclipse.core.commands.operations.OperationHistoryEvent
182 */
183 void addOperationHistoryListener(IOperationHistoryListener listener);
184
185 /**
186 * <p>
187 * Close the current operation. If the operation has successfully completed,
188 * send listeners a <code>DONE</code>, <code>UNDONE</code>, or
189 * <code>REDONE</code> notification, depending on the mode. Otherwise send
190 * an <code>OPERATION_NOT_OK</code> notification. Add the operation to the
191 * history if specified and send an <code>OPERATION_ADDED</code>
192 * notification.
193 * </p>
194 * <p>
195 * Any operations that are executed and added after this operation is closed
196 * will no longer be considered part of this operation.
197 * </p>
198 * <p>
199 * This method has no effect if the caller has not previously called
200 * {@link #openOperation}.
201 * </p>
202 *
203 * @param operationOK
204 * <code>true</code> if the operation successfully completed.
205 * Listeners should be notified with <code>DONE</code>,
206 * <code>UNDONE</code>, or <code>REDONE</code>.
207 * <code>false</code> if the operation did not successfully
208 * complete. Listeners should be notified with
209 * <code>OPERATION_NOT_OK</code>.
210 * @param addToHistory
211 * <code>true</code> if the operation should be added to the
212 * history, <code>false</code> if it should not. If the
213 * <code>operationOK</code> parameter is <code>false</code>,
214 * the operation will never be added to the history.
215 * @param mode
216 * the mode the operation was opened in. Can be one of
217 * <code>EXECUTE</code>, <code>UNDO</code>, or
218 * <code>REDO</code>. This determines what notifications are
219 * sent.
220 */
221 void closeOperation(bool operationOK, bool addToHistory, int mode);
222
223 /**
224 * <p>
225 * Return whether there is a valid redoable operation available in the given
226 * context.
227 * </p>
228 *
229 * @param context
230 * the context to be checked
231 * @return <code>true</code> if there is a redoable operation,
232 * <code>false</code> otherwise.
233 */
234
235 bool canRedo(IUndoContext context);
236
237 /**
238 * <p>
239 * Return whether there is a valid undoable operation available in the given
240 * context
241 * </p>
242 *
243 * @param context
244 * the context to be checked
245 * @return <code>true</code> if there is an undoable operation,
246 * <code>false</code> otherwise.
247 */
248 bool canUndo(IUndoContext context);
249
250 /**
251 * <p>
252 * Dispose of the specified context in the history. All operations that have
253 * only the given context will be disposed. References to the context in
254 * operations that have more than one context will also be removed. A
255 * history notification for the removal of each operation being disposed
256 * will be sent.
257 * </p>
258 *
259 * @param context
260 * the context to be disposed
261 * @param flushUndo
262 * <code>true</code> if the context should be flushed from the
263 * undo history, <code>false</code> if it should not
264 * @param flushRedo
265 * <code>true</code> if the context should be flushed from the
266 * redo history, <code>false</code> if it should not.
267 * @param flushContext
268 * <code>true</code> if the context is no longer in use and
269 * references to it should be flushed.
270 */
271 void dispose(IUndoContext context, bool flushUndo, bool flushRedo,
272 bool flushContext);
273
274 /**
275 * <p>
276 * Execute the specified operation and add it to the operations history if
277 * successful. This method is used by clients who wish operation history
278 * listeners to receive notifications before and after the execution of the
279 * operation. Execution of the operation is subject to approval by any
280 * registered {@link IOperationApprover2}. If execution is approved,
281 * listeners will be notified before (<code>ABOUT_TO_EXECUTE</code>) and
282 * after (<code>DONE</code> or <code>OPERATION_NOT_OK</code>).
283 * </p>
284 * <p>
285 * If the operation successfully executes, an additional notification that
286 * the operation has been added to the history (<code>OPERATION_ADDED</code>)
287 * will be sent.
288 * </p>
289 *
290 * @param operation
291 * the operation to be executed and then added to the history
292 *
293 * @param monitor
294 * the progress monitor to be used (or <code>null</code>)
295 * during the operation.
296 *
297 * @param info
298 * the IAdaptable (or <code>null</code>) provided by the
299 * caller in order to supply UI information for prompting the
300 * user if necessary. When this parameter is not
301 * <code>null</code>, it should minimally contain an adapter
302 * for the org.eclipse.swt.widgets.Shell.class.
303 *
304 * @return the IStatus indicating whether the execution succeeded.
305 *
306 * <p>
307 * The severity code in the returned status describes whether the operation
308 * succeeded and whether it was added to the history. <code>OK</code>
309 * severity indicates that the execute operation was successful and that the
310 * operation has been added to the history. Listeners will receive
311 * notifications about the operation's success (<code>DONE</code>) and
312 * about the operation being added to the history (<code>OPERATION_ADDED</code>).
313 * </p>
314 * <p>
315 * <code>CANCEL</code> severity indicates that the user cancelled the
316 * operation and that the operation was not added to the history.
317 * <code>ERROR</code> severity indicates that the operation did not
318 * successfully execute and that it was not added to the history. Any other
319 * severity code is not specifically interpreted by the history, and the
320 * operation will not be added to the history. For all severities other than
321 * <code>OK</code>, listeners will receive the
322 * <code>OPERATION_NOT_OK</code> notification instead of the
323 * <code>DONE</code> notification if the execution was approved and
324 * attempted.
325 * </p>
326 *
327 * @throws ExecutionException
328 * if an exception occurred during execution.
329 *
330 */
331 IStatus execute(IUndoableOperation operation, IProgressMonitor monitor,
332 IAdaptable info);
333
334 /**
335 * <p>
336 * Return the limit on the undo and redo history for a particular context.
337 * </p>
338 *
339 * @param context
340 * the context whose limit is requested
341 *
342 * @return the undo and redo history limit for the specified context.
343 */
344 int getLimit(IUndoContext context);
345
346 /**
347 * <p>
348 * Get the array of operations in the redo history for a the specified undo
349 * context. The operations are in the order that they were added to the
350 * history, with the most recently undone operation appearing last in the
351 * array. This history is used LIFO (last in, first out) when successive
352 * "Redo" commands are invoked.
353 *
354 * </p>
355 *
356 * @param context
357 * the context for the redo
358 * @return the array of operations in the history
359 */
360 IUndoableOperation[] getRedoHistory(IUndoContext context);
361
362 /**
363 * <p>
364 * Get the operation that will next be redone in the given undo context.
365 * </p>
366 *
367 * @param context
368 * the context for the redo
369 * @return the operation to be redone or <code>null</code> if there is no
370 * operation available. There is no guarantee that the returned
371 * operation is valid for redo.
372 */
373 IUndoableOperation getRedoOperation(IUndoContext context);
374
375 /**
376 * <p>
377 * Get the array of operations in the undo history for the specified undo
378 * context. The operations are in the order that they were added to the
379 * history, with the most recently added operation appearing last in the
380 * array. This history is used LIFO (last in, first out) when successive
381 * "Undo" commands are invoked.
382 * </p>
383 *
384 * @param context
385 * the context for the undo
386 * @return the array of operations in the history
387 */
388 IUndoableOperation[] getUndoHistory(IUndoContext context);
389
390 /**
391 * <p>
392 * Open this composite operation and consider it an operation that contains
393 * other related operations. Consider all operations that are subsequently
394 * executed or added to be part of this operation. When an operation is
395 * opened, listeners will immediately receive a notification for the opened
396 * operation. The specific notification depends on the mode in which the
397 * operation is opened (<code>ABOUT_TO_EXECUTE</code>,
398 * <code>ABOUT_TO_UNDO</code>, <code>ABOUT_TO_REDO</code>).
399 * Notifications for any other execute or add while this operation is open
400 * will not occur. Instead, those operations will be added to the current
401 * operation.
402 * </p>
403 * <p>
404 * Note: This method is intended to be used by legacy undo frameworks that
405 * do not expect related undo operations to appear in the same undo history
406 * as the triggering undo operation. When an operation is open, any
407 * subsequent requests to execute, add, undo, or redo another operation will
408 * result in that operation being added to the open operation. Once the
409 * operation is closed, the composite will be considered an atomic
410 * operation. Clients should not modify the composite directly (by adding
411 * and removing children) while it is open.
412 * </p>
413 * <p>
414 * When a composite is open, operations that are added to the history will
415 * be considered part of the open operation instead. Operations that are
416 * executed while a composite is open will first be executed and then added
417 * to the composite.
418 * </p>
419 * <p>
420 * Open operations cannot be nested. If this method is called when a
421 * different operation is open, it is presumed to be an application coding
422 * error and this method will throw an IllegalStateException.
423 * </p>
424 *
425 * @param operation
426 * the composite operation to be considered as the parent for all
427 * subsequent operations.
428 * @param mode
429 * the mode the operation is executing in. Can be one of
430 * <code>EXECUTE</code>, <code>UNDO</code>, or
431 * <code>REDO</code>. This determines what notifications are
432 * sent.
433 */
434 void openOperation(ICompositeOperation operation, int mode);
435
436 /**
437 * <p>
438 * The specified operation has changed in some way since it was added to the
439 * operation history. Notify listeners with an OPERATION_CHANGED event.
440 * </p>
441 *
442 * @param operation
443 * the operation that has changed.
444 *
445 */
446 void operationChanged(IUndoableOperation operation);
447
448 /**
449 * <p>
450 * Get the operation that will next be undone in the given undo context.
451 * </p>
452 *
453 * @param context
454 * the context for the undo
455 * @return the operation to be undone or <code>null</code> if there is no
456 * operation available. There is no guarantee that the available
457 * operation is valid for the undo.
458 */
459 IUndoableOperation getUndoOperation(IUndoContext context);
460
461 /**
462 * <p>
463 * Redo the most recently undone operation in the given context. The redo of
464 * the operation is subject to approval by any registered
465 * {@link IOperationApprover} before it is attempted.
466 * </p>
467 *
468 * @param context
469 * the context to be redone
470 * @param monitor
471 * the progress monitor to be used for the redo, or
472 * <code>null</code> if no progress monitor is provided.
473 * @param info
474 * the IAdaptable (or <code>null</code>) provided by the
475 * caller in order to supply UI information for prompting the
476 * user if necessary. When this parameter is not
477 * <code>null</code>, it should minimally contain an adapter
478 * for the org.eclipse.swt.widgets.Shell.class.
479 * @return the IStatus indicating whether the redo succeeded.
480 *
481 * <p>
482 * The severity code in the returned status describes whether the operation
483 * succeeded and whether it remains in the history. <code>OK</code>
484 * severity indicates that the redo operation was successful and (since
485 * release 3.2), that the operation will be placed in the undo history.
486 * (Prior to 3.2, a successfully redone operation would not be placed on the
487 * undo history if it could not be undone. Since 3.2, this is relaxed, and
488 * all successfully redone operations are placed in the undo history.)
489 * Listeners will receive the <code>REDONE</code> notification.
490 * </p>
491 * <p>
492 * Other severity codes (<code>CANCEL</code>, <code>ERROR</code>,
493 * <code>INFO</code>, etc.) are not specifically interpreted by the
494 * history. The operation will remain in the history and the returned status
495 * is simply passed back to the caller. For all severities other than
496 * <code>OK</code>, listeners will receive the
497 * <code>OPERATION_NOT_OK</code> notification instead of the
498 * <code>REDONE</code> notification if the redo was approved and
499 * attempted.
500 * </p>
501 *
502 * @throws ExecutionException
503 * if an exception occurred during redo.
504 *
505 */
506 IStatus redo(IUndoContext context, IProgressMonitor monitor, IAdaptable info);
507
508 /**
509 * <p>
510 * Redo the specified operation. The redo of the operation is subject to
511 * approval by any registered {@link IOperationApprover} before it is
512 * attempted.
513 * </p>
514 *
515 * @param operation
516 * the operation to be redone
517 * @param monitor
518 * the progress monitor to be used for the redo, or code>null</code>
519 * if no progress monitor is provided
520 * @param info
521 * the IAdaptable (or <code>null</code>) provided by the
522 * caller in order to supply UI information for prompting the
523 * user if necessary. When this parameter is not <code>null</code>,
524 * it should minimally contain an adapter for the
525 * org.eclipse.swt.widgets.Shell.class.
526 *
527 * @return the IStatus indicating whether the redo succeeded.
528 *
529 * <p>
530 * The severity code in the returned status describes whether the operation
531 * succeeded and whether it remains in the history. <code>OK</code>
532 * severity indicates that the redo operation was successful, and (since
533 * release 3.2), that the operation will be placed in the undo history.
534 * (Prior to 3.2, a successfully redone operation would not be placed on the
535 * undo history if it could not be undone. Since 3.2, this is relaxed, and
536 * all successfully redone operations are placed in the undo history.)
537 * Listeners will receive the <code>REDONE</code> notification.
538 * </p>
539 * <p>
540 * Other severity codes (<code>CANCEL</code>, <code>ERROR</code>,
541 * <code>INFO</code>, etc.) are not specifically interpreted by the
542 * history. The operation will remain in the history and the returned status
543 * is simply passed back to the caller. For all severities other than <code>OK</code>,
544 * listeners will receive the <code>OPERATION_NOT_OK</code> notification
545 * instead of the <code>REDONE</code> notification if the redo was
546 * approved and attempted.
547 * </p>
548 *
549 * @throws ExecutionException
550 * if an exception occurred during redo.
551 */
552 IStatus redoOperation(IUndoableOperation operation,
553 IProgressMonitor monitor, IAdaptable info);
554
555 /**
556 * <p>
557 * Remove the specified operation approver from the list of operation
558 * approvers that are consulted before an operation is undone or redone.
559 * </p>
560 *
561 * @param approver
562 * the IOperationApprover to be removed. Must not be
563 * <code>null</code>. If an attempt is made to remove an
564 * instance which is not already registered with this instance,
565 * this method has no effect.
566 */
567 void removeOperationApprover(IOperationApprover approver);
568
569 /**
570 * <p>
571 * Remove the specified listener from the list of operation history
572 * listeners.
573 * </p>
574 *
575 * @param listener
576 * The IOperationHistoryListener to be removed. Must not be
577 * <code>null</code>. If an attempt is made to remove an
578 * instance which is not already registered with this instance,
579 * this method has no effect.
580 */
581 void removeOperationHistoryListener(IOperationHistoryListener listener);
582
583 /**
584 * <p>
585 * Replace the specified operation in the undo or redo history with the
586 * provided list of replacements. This protocol is typically used when a
587 * composite is broken up into its atomic parts. The replacements will be
588 * inserted so that the first replacement will be the first of the
589 * replacements to be undone or redone. Listeners will be notified about the
590 * removal of the replaced element and the addition of each replacement.
591 * </p>
592 *
593 * @param operation
594 * The IUndoableOperation to be replaced
595 * @param replacements
596 * the array of IUndoableOperation to replace the first operation
597 */
598 void replaceOperation(IUndoableOperation operation,
599 IUndoableOperation[] replacements);
600
601 /**
602 * <p>
603 * Set the limit on the undo and redo history for a particular context.
604 * </p>
605 *
606 * @param context
607 * the context whose limit is being set.
608 *
609 * @param limit
610 * the maximum number of operations that should be kept in the
611 * undo or redo history for the specified context. Must not be
612 * negative.
613 */
614 void setLimit(IUndoContext context, int limit);
615
616 /**
617 * <p>
618 * Undo the most recently executed operation in the given context. The undo
619 * of the operation is subject to approval by any registered
620 * {@link IOperationApprover} before it is attempted.
621 * </p>
622 *
623 * @param context
624 * the context to be undone
625 * @param monitor
626 * the progress monitor to be used for the undo, or
627 * <code>null</code> if no progress monitor is provided.
628 * @param info
629 * the IAdaptable (or <code>null</code>) provided by the
630 * caller in order to supply UI information for prompting the
631 * user if necessary. When this parameter is not
632 * <code>null</code>, it should minimally contain an adapter
633 * for the org.eclipse.swt.widgets.Shell.class.
634 *
635 * @return the IStatus indicating whether the undo succeeded.
636 *
637 * <p>
638 * The severity code in the returned status describes whether the operation
639 * succeeded and whether it remains in the history. <code>OK</code>
640 * severity indicates that the undo operation was successful, and (since
641 * release 3.2), that the operation will be placed on the redo history.
642 * (Prior to 3.2, a successfully undone operation would not be placed on the
643 * redo history if it could not be redone. Since 3.2, this is relaxed, and
644 * all successfully undone operations are placed in the redo history.)
645 * Listeners will receive the <code>UNDONE</code> notification.
646 * </p>
647 * <p>
648 * Other severity codes (<code>CANCEL</code>, <code>ERROR</code>,
649 * <code>INFO</code>, etc.) are not specifically interpreted by the
650 * history. The operation will remain in the history and the returned status
651 * is simply passed back to the caller. For all severities other than
652 * <code>OK</code>, listeners will receive the
653 * <code>OPERATION_NOT_OK</code> notification instead of the
654 * <code>UNDONE</code> notification if the undo was approved and
655 * attempted.
656 * </p>
657 *
658 * @throws ExecutionException
659 * if an exception occurred during undo.
660 */
661
662 IStatus undo(IUndoContext context, IProgressMonitor monitor, IAdaptable info);
663
664 /**
665 * <p>
666 * Undo the specified operation. The undo of the operation is subject to
667 * approval by any registered {@link IOperationApprover} before it is
668 * attempted.
669 * </p>
670 *
671 * @param operation
672 * the operation to be undone
673 * @param monitor
674 * the progress monitor to be used for the undo, or
675 * <code>null</code> if no progress monitor is provided
676 * @param info
677 * the IAdaptable (or <code>null</code>) provided by the
678 * caller in order to supply UI information for prompting the
679 * user if necessary. When this parameter is not
680 * <code>null</code>, it should minimally contain an adapter
681 * for the org.eclipse.swt.widgets.Shell.class.
682 *
683 * @return the IStatus indicating whether the undo succeeded.
684 *
685 * <p>
686 * The severity code in the returned status describes whether the operation
687 * succeeded and whether it remains in the history. <code>OK</code>
688 * severity indicates that the undo operation was successful, and (since
689 * release 3.2), that the operation will be placed on the redo history.
690 * (Prior to 3.2, a successfully undone operation would not be placed on the
691 * redo history if it could not be redone. Since 3.2, this is relaxed, and
692 * all successfully undone operations are placed in the redo history.)
693 * Listeners will receive the <code>UNDONE</code> notification.
694 * </p>
695 * <p>
696 * Other severity codes (<code>CANCEL</code>, <code>ERROR</code>,
697 * <code>INFO</code>, etc.) are not specifically interpreted by the
698 * history. The operation will remain in the history and the returned status
699 * is simply passed back to the caller. For all severities other than
700 * <code>OK</code>, listeners will receive the
701 * <code>OPERATION_NOT_OK</code> notification instead of the
702 * <code>UNDONE</code> notification if the undo was approved and
703 * attempted.
704 * </p>
705 *
706 * @throws ExecutionException
707 * if an exception occurred during undo.
708 */
709 IStatus undoOperation(IUndoableOperation operation,
710 IProgressMonitor monitor, IAdaptable info);
711
712 }