| /******************************************************************************* |
| * Copyright (c) 2012 Oracle. 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: |
| * Oracle - initial API and implementation |
| ******************************************************************************/ |
| package org.eclipse.jpt.common.utility.command; |
| |
| import java.io.Serializable; |
| import org.eclipse.jpt.common.utility.internal.StringTools; |
| |
| /** |
| * This interface extends the normal command executor; it allows the client |
| * to specify when a command <em>must</em> be executed synchronously. |
| * <p> |
| * Provisional API: This interface is part of an interim API that is still |
| * under development and expected to change significantly before reaching |
| * stability. It is available at this early stage to solicit feedback from |
| * pioneering adopters on the understanding that any code that uses this API |
| * will almost certainly be broken (repeatedly) as the API evolves. |
| */ |
| public interface ExtendedCommandExecutor |
| extends CommandExecutor |
| { |
| /** |
| * Suspend the current thread until the specified command is executed. |
| * The command itself must be executed <em>after</em> any other commands |
| * previously passed to the command executor (at least when passed |
| * from clients executing on the same thread). |
| * @see #execute(Command) |
| */ |
| void waitToExecute(Command command) throws InterruptedException; |
| |
| /** |
| * Suspend the current thread until the specified command is executed |
| * or the specified time-out occurs. |
| * The time-out is specified in milliseconds. Return <code>true</code> if |
| * the command was executed in the allotted time; |
| * return <code>false</code> if a time-out occurred and the command was |
| * <em>not</em> executed. |
| * If the time-out is zero, wait indefinitely. |
| * <p> |
| * The command itself must be executed <em>after</em> any other commands |
| * previously passed to the command executor (at least when passed |
| * from clients executing on the same thread). |
| * @see #execute(Command) |
| */ |
| boolean waitToExecute(Command command, long timeout) throws InterruptedException; |
| |
| |
| /** |
| * Singleton implementation of the command executor interface |
| * that simply executes the command without any sort of enhancement. |
| */ |
| final class Default |
| implements ExtendedCommandExecutor, Serializable |
| { |
| public static final ExtendedCommandExecutor INSTANCE = new Default(); |
| public static ExtendedCommandExecutor instance() { |
| return INSTANCE; |
| } |
| // ensure single instance |
| private Default() { |
| super(); |
| } |
| public void execute(Command command) { |
| command.execute(); |
| } |
| public void waitToExecute(Command command) { |
| command.execute(); |
| } |
| public boolean waitToExecute(Command command, long timeout) { |
| command.execute(); |
| return true; |
| } |
| @Override |
| public String toString() { |
| return StringTools.buildSingletonToString(this); |
| } |
| private static final long serialVersionUID = 1L; |
| private Object readResolve() { |
| // replace this object with the singleton |
| return INSTANCE; |
| } |
| } |
| |
| |
| /** |
| * Singleton implementation of the command executor interface |
| * that ignores any commands. |
| */ |
| final class Inactive |
| implements ExtendedCommandExecutor, Serializable |
| { |
| public static final ExtendedCommandExecutor INSTANCE = new Inactive(); |
| public static ExtendedCommandExecutor instance() { |
| return INSTANCE; |
| } |
| // ensure single instance |
| private Inactive() { |
| super(); |
| } |
| public void execute(Command command) { |
| // do nothing |
| } |
| public void waitToExecute(Command command) { |
| // do nothing |
| } |
| public boolean waitToExecute(Command command, long timeout) { |
| // do nothing |
| return true; |
| } |
| @Override |
| public String toString() { |
| return StringTools.buildSingletonToString(this); |
| } |
| private static final long serialVersionUID = 1L; |
| private Object readResolve() { |
| // replace this object with the singleton |
| return INSTANCE; |
| } |
| } |
| } |