| /******************************************************************************* |
| * Copyright (c) 2005, 2008 IBM Corporation and others. |
| * All rights reserved. This program and the accompanying materials |
| * are made available under the terms of the Eclipse Public License v1.0 |
| * which accompanies this distribution, and is available at |
| * http://www.eclipse.org/legal/epl-v10.html |
| * |
| * Contributors: |
| * IBM Corporation - initial API and implementation |
| *******************************************************************************/ |
| package org.eclipse.core.commands.operations; |
| |
| import org.eclipse.core.commands.ExecutionException; |
| import org.eclipse.core.runtime.IAdaptable; |
| import org.eclipse.core.runtime.IProgressMonitor; |
| import org.eclipse.core.runtime.IStatus; |
| |
| /** |
| * <p> |
| * IUndoableOperation defines an operation that can be executed, undone, and |
| * redone. Operations typically have fully defined parameters. That is, they are |
| * usually created after the user has been queried for any input needed to |
| * define the operation. |
| * </p> |
| * <p> |
| * Operations determine their ability to execute, undo, or redo according to the |
| * current state of the application. They do not make decisions about their |
| * validity based on where they occur in the operation history. That is left to |
| * the particular operation history. |
| * </p> |
| * |
| * @since 3.1 |
| */ |
| public interface IUndoableOperation { |
| |
| /** |
| * <p> |
| * Add the specified context to the operation. If a context equal to the |
| * specified context is already present, do not add it again. Note that |
| * determining whether a context is already present is based on equality, |
| * not whether the context matches ({@link IUndoContext#matches(IUndoContext)}) |
| * another context. |
| * </p> |
| * |
| * @param context |
| * the context to be added |
| */ |
| void addContext(IUndoContext context); |
| |
| /** |
| * <p> |
| * Returns whether the operation can be executed in its current state. |
| * </p> |
| * |
| * <p> |
| * Note: The computation for this method must be fast, as it is called |
| * frequently. If necessary, this method can be optimistic in its |
| * computation (returning true) and later perform more time-consuming |
| * computations during the actual execution of the operation, returning the |
| * appropriate status if the operation cannot actually execute at that time. |
| * </p> |
| * |
| * @return <code>true</code> if the operation can be executed; |
| * <code>false</code> otherwise. |
| */ |
| boolean canExecute(); |
| |
| /** |
| * <p> |
| * Returns whether the operation can be redone in its current state. |
| * </p> |
| * |
| * <p> |
| * Note: The computation for this method must be fast, as it is called |
| * frequently. If necessary, this method can be optimistic in its |
| * computation (returning true) and later perform more time-consuming |
| * computations during the actual redo of the operation, returning the |
| * appropriate status if the operation cannot actually be redone at that |
| * time. |
| * </p> |
| * |
| * @return <code>true</code> if the operation can be redone; |
| * <code>false</code> otherwise. |
| */ |
| boolean canRedo(); |
| |
| /** |
| * <p> |
| * Returns whether the operation can be undone in its current state. |
| * </p> |
| * |
| * <p> |
| * Note: The computation for this method must be fast, as it is called |
| * frequently. If necessary, this method can be optimistic in its |
| * computation (returning true) and later perform more time-consuming |
| * computations during the actual undo of the operation, returning the |
| * appropriate status if the operation cannot actually be undone at that |
| * time. |
| * </p> |
| * |
| * @return <code>true</code> if the operation can be undone; |
| * <code>false</code> otherwise. |
| */ |
| boolean canUndo(); |
| |
| /** |
| * Dispose of the operation. This method is used when the operation is no |
| * longer kept in the history. Implementers of this method typically |
| * unregister any listeners. |
| * |
| */ |
| void dispose(); |
| |
| /** |
| * Execute the operation. This method should only be called the first time |
| * that an operation is executed. |
| * |
| * @param monitor |
| * the progress monitor (or <code>null</code>) to use for |
| * reporting progress to the user. |
| * @param info |
| * the IAdaptable (or <code>null</code>) provided by the |
| * caller in order to supply UI information for prompting the |
| * user if necessary. When this parameter is not |
| * <code>null</code>, it should minimally contain an adapter |
| * for the org.eclipse.swt.widgets.Shell.class. |
| * |
| * @return the IStatus of the execution. The status severity should be set |
| * to <code>OK</code> if the operation was successful, and |
| * <code>ERROR</code> if it was not. Any other status is assumed |
| * to represent an incompletion of the execution. |
| * @throws ExecutionException |
| * if an exception occurred during execution. |
| */ |
| IStatus execute(IProgressMonitor monitor, IAdaptable info) |
| throws ExecutionException; |
| |
| /** |
| * <p> |
| * Returns the array of contexts that have been assigned to the operation. |
| * </p> |
| * <p> |
| * This method may be called by the operation history from inside a |
| * synchronized block. To avoid deadlock conditions, implementers of this |
| * method must avoid dispatching and waiting on threads that modify the |
| * operation history during this method. |
| * </p> |
| * |
| * @return the array of contexts |
| */ |
| IUndoContext[] getContexts(); |
| |
| /** |
| * Return the label that should be used to show the name of the operation to |
| * the user. This label is typically combined with the command strings shown |
| * to the user in "Undo" and "Redo" user interfaces. |
| * |
| * @return the String label. Should never be <code>null</code>. |
| */ |
| String getLabel(); |
| |
| /** |
| * <p> |
| * Returns whether the operation has a matching context for the specified |
| * context. |
| * </p> |
| * <p> |
| * This method may be called by the operation history from inside a |
| * synchronized block. To avoid deadlock conditions, implementers of this |
| * method must avoid dispatching and waiting on threads that modify the |
| * operation history during this method. |
| * </p> |
| * |
| * @see IUndoContext#matches(IUndoContext) |
| * |
| * @param context |
| * the context in question |
| * @return <code>true</code> if the context is present, <code>false</code> |
| * if it is not. |
| */ |
| boolean hasContext(IUndoContext context); |
| |
| /** |
| * Redo the operation. This method should only be called after an operation |
| * has been undone. |
| * |
| * @param monitor |
| * the progress monitor (or <code>null</code>) to use for |
| * reporting progress to the user. |
| * @param info |
| * the IAdaptable (or <code>null</code>) provided by the |
| * caller in order to supply UI information for prompting the |
| * user if necessary. When this parameter is not |
| * <code>null</code>, it should minimally contain an adapter |
| * for the org.eclipse.swt.widgets.Shell.class. |
| * @return the IStatus of the redo. The status severity should be set to |
| * <code>OK</code> if the redo was successful, and |
| * <code>ERROR</code> if it was not. Any other status is assumed |
| * to represent an incompletion of the redo. |
| * @throws ExecutionException |
| * if an exception occurred during redo. |
| */ |
| |
| IStatus redo(IProgressMonitor monitor, IAdaptable info) |
| throws ExecutionException; |
| |
| /** |
| * Remove the specified context from the operation. This method has no |
| * effect if the context is not equal to another context in the context |
| * list. Note that determining whether a context is present when removing it |
| * is based on equality, not whether the context matches ({@link |
| * IUndoContext#matches(IUndoContext)}) another context. |
| * |
| * @param context |
| * the context to be removed |
| */ |
| void removeContext(IUndoContext context); |
| |
| /** |
| * Undo the operation. This method should only be called after an operation |
| * has been executed. |
| * |
| * @param monitor |
| * the progress monitor (or <code>null</code>) to use for |
| * reporting progress to the user. |
| * @param info |
| * the IAdaptable (or <code>null</code>) provided by the |
| * caller in order to supply UI information for prompting the |
| * user if necessary. When this parameter is not |
| * <code>null</code>, it should minimally contain an adapter |
| * for the org.eclipse.swt.widgets.Shell.class. |
| * @return the IStatus of the undo. The status severity should be set to |
| * <code>OK</code> if the redo was successful, and |
| * <code>ERROR</code> if it was not. Any other status is assumed |
| * to represent an incompletion of the undo. |
| * @throws ExecutionException |
| * if an exception occurred during undo. |
| */ |
| IStatus undo(IProgressMonitor monitor, IAdaptable info) |
| throws ExecutionException; |
| |
| } |