| /******************************************************************************* |
| * Copyright (c) 2005, 2006 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.runtime.IAdaptable; |
| import org.eclipse.core.runtime.IStatus; |
| import org.eclipse.core.runtime.Status; |
| |
| /** |
| * <p> |
| * An abstract class for detecting violations in a strict linear undo/redo |
| * model. Once a violation is detected, subclasses implement the specific |
| * behavior for indicating whether or not the undo/redo should proceed. |
| * </p> |
| * |
| * @since 3.1 |
| */ |
| public abstract class LinearUndoViolationDetector implements IOperationApprover { |
| |
| /** |
| * Create an instance of LinearUndoViolationDetector. |
| */ |
| public LinearUndoViolationDetector() { |
| super(); |
| } |
| |
| /** |
| * Return a status indicating whether a linear redo violation is allowable. |
| * A linear redo violation is defined as a request to redo a particular |
| * operation even if it is not the most recently added operation to the redo |
| * history. |
| * |
| * @param operation |
| * the operation for which a linear redo violation has been |
| * detected. |
| * @param context |
| * the undo context in which the linear redo violation exists |
| * @param history |
| * the operation history containing the operation |
| * @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 describing whether the redo violation is allowed. The |
| * redo will not proceed if the status severity is not |
| * <code>OK</code>, and the caller requesting the redo will be |
| * returned the status that caused the rejection. Specific status |
| * severities will not be interpreted by the history. |
| */ |
| |
| protected abstract IStatus allowLinearRedoViolation( |
| IUndoableOperation operation, IUndoContext context, |
| IOperationHistory history, IAdaptable info); |
| |
| /** |
| * Return a status indicating whether a linear undo violation is allowable. |
| * A linear undo violation is defined as a request to undo a particular |
| * operation even if it is not the most recently added operation to the undo |
| * history. |
| * |
| * @param operation |
| * the operation for which a linear undo violation has been |
| * detected. |
| * @param context |
| * the undo context in which the linear undo violation exists |
| * @param history |
| * the operation history containing the operation |
| * @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 describing whether the undo violation is allowed. The |
| * undo will not proceed if the status severity is not |
| * <code>OK</code>, and the caller requesting the undo will be |
| * returned the status that caused the rejection. Specific status |
| * severities will not be interpreted by the history. |
| */ |
| protected abstract IStatus allowLinearUndoViolation( |
| IUndoableOperation operation, IUndoContext context, |
| IOperationHistory history, IAdaptable info); |
| |
| /* |
| * (non-Javadoc) |
| * |
| * @see org.eclipse.core.commands.operations.IOperationApprover#proceedRedoing(org.eclipse.core.commands.operations.IUndoableOperation, |
| * org.eclipse.core.commands.operations.IOperationHistory, |
| * org.eclipse.core.runtime.IAdaptable) |
| */ |
| public final IStatus proceedRedoing(IUndoableOperation operation, |
| IOperationHistory history, IAdaptable info) { |
| IUndoContext[] contexts = operation.getContexts(); |
| for (int i = 0; i < contexts.length; i++) { |
| IUndoContext context = contexts[i]; |
| if (history.getRedoOperation(context) != operation) { |
| IStatus status = allowLinearRedoViolation(operation, context, |
| history, info); |
| if (!status.isOK()) { |
| return status; |
| } |
| } |
| } |
| return Status.OK_STATUS; |
| } |
| |
| /* |
| * (non-Javadoc) |
| * |
| * @see org.eclipse.core.commands.operations.IOperationApprover#proceedUndoing(org.eclipse.core.commands.operations.IUndoableOperation, |
| * org.eclipse.core.commands.operations.IOperationHistory, |
| * org.eclipse.core.runtime.IAdaptable) |
| */ |
| |
| public final IStatus proceedUndoing(IUndoableOperation operation, |
| IOperationHistory history, IAdaptable info) { |
| IUndoContext[] contexts = operation.getContexts(); |
| for (int i = 0; i < contexts.length; i++) { |
| IUndoContext context = contexts[i]; |
| if (history.getUndoOperation(context) != operation) { |
| IStatus status = allowLinearUndoViolation(operation, context, |
| history, info); |
| if (!status.isOK()) { |
| return status; |
| } |
| } |
| } |
| return Status.OK_STATUS; |
| } |
| } |