| /** |
| * <copyright> |
| * |
| * Copyright (c) 2002-2004 IBM Corporation and others. |
| * All rights reserved. This program and the accompanying materials |
| * are made available under the terms of the Common Public License v1.0 |
| * which accompanies this distribution, and is available at |
| * http://www.eclipse.org/legal/cpl-v10.html |
| * |
| * Contributors: |
| * IBM - Initial API and implementation |
| * |
| * </copyright> |
| * |
| * $Id: IdentityCommand.java,v 1.3 2005/06/06 05:36:11 david_williams Exp $ |
| */ |
| package org.eclipse.emf.common.command; |
| |
| |
| import java.util.Collection; |
| import java.util.Collections; |
| |
| |
| /** |
| * A command that always produces the same result. |
| */ |
| public class IdentityCommand extends AbstractCommand { |
| /** |
| * An empty instance of this object. |
| */ |
| public static final IdentityCommand INSTANCE = new IdentityCommand(); |
| |
| /** |
| * Keeps track of the result returned from {@link #getResult}. |
| */ |
| protected Collection result; |
| |
| { |
| // This ensures that these useless state variables at least reflect |
| // the right value. |
| // |
| isPrepared = true; |
| isExecutable = true; |
| } |
| |
| /** |
| * Creates an empty instance. |
| */ |
| public IdentityCommand() { |
| super(); |
| this.result = Collections.EMPTY_LIST; |
| } |
| |
| /** |
| * Creates an instance with a result collection containing the given |
| * result object. |
| * |
| * @param result |
| * the one object in the result collection. |
| */ |
| public IdentityCommand(Object result) { |
| super(); |
| this.result = Collections.singleton(result); |
| } |
| |
| /** |
| * Creates an instance with the given result collection. |
| * |
| * @param result |
| * the result collection. |
| */ |
| public IdentityCommand(Collection result) { |
| super(); |
| this.result = result; |
| } |
| |
| /** |
| * Creates an instance with the given label. |
| * |
| * @param label |
| * the label. |
| */ |
| public IdentityCommand(String label) { |
| this.label = label; |
| this.result = Collections.EMPTY_LIST; |
| } |
| |
| /** |
| * Creates an instance with the given label and a result collection |
| * containing the given result object. |
| * |
| * @param label |
| * the label. |
| * @param result |
| * the one object in the result collection. |
| */ |
| public IdentityCommand(String label, Object result) { |
| this.label = label; |
| this.result = Collections.singleton(result); |
| } |
| |
| /** |
| * Creates an instance with the given label the result collection. |
| * |
| * @param label |
| * the label. |
| * @param result |
| * the result collection. |
| */ |
| public IdentityCommand(String label, Collection result) { |
| this.label = label; |
| this.result = result; |
| } |
| |
| /** |
| * Creates an instance with the given label and description. |
| * |
| * @param label |
| * the label. |
| * @param description |
| * the description. |
| */ |
| public IdentityCommand(String label, String description) { |
| this.label = label; |
| this.description = description; |
| this.result = Collections.EMPTY_LIST; |
| } |
| |
| /** |
| * Creates an instance with the given label, description, and a result |
| * collection containing the given result object. |
| * |
| * @param label |
| * the label. |
| * @param description |
| * the description. |
| * @param result |
| * the one object in the result collection. |
| */ |
| public IdentityCommand(String label, String description, Object result) { |
| this.label = label; |
| this.description = description; |
| this.result = Collections.singleton(result); |
| } |
| |
| /** |
| * Creates an instance with the given label, description, result |
| * collection. |
| * |
| * @param label |
| * the label. |
| * @param description |
| * the description. |
| * @param result |
| * the result collection. |
| */ |
| public IdentityCommand(String label, String description, Collection result) { |
| this.label = label; |
| this.description = description; |
| this.result = result; |
| } |
| |
| /** |
| * Returns <code>true</code>. |
| * |
| * @return <code>true</code>. |
| */ |
| public boolean canExecute() { |
| return true; |
| } |
| |
| /** |
| * Do nothing. |
| */ |
| public void execute() { |
| } |
| |
| /** |
| * Do nothing. |
| */ |
| public void undo() { |
| } |
| |
| /** |
| * Do nothing. |
| */ |
| public void redo() { |
| } |
| |
| /* |
| * Javadoc copied from base class. |
| */ |
| public String getLabel() { |
| return label == null ? UnDoCommonMessages._UI_IdentityCommand_label : label; |
| } |
| |
| /* |
| * Javadoc copied from base class. |
| */ |
| public String getDescription() { |
| return description == null ? UnDoCommonMessages._UI_IdentityCommand_description : description; |
| } |
| |
| /** |
| * Return the identity result. |
| * |
| * @return the identity result. |
| */ |
| public Collection getResult() { |
| return result; |
| } |
| } |