diff options
Diffstat (limited to 'common/plugins/org.eclipse.jpt.common.utility/src/org/eclipse/jpt/common/utility/internal/command/AbstractSingleUseQueueingCommandExecutor.java')
| -rw-r--r-- | common/plugins/org.eclipse.jpt.common.utility/src/org/eclipse/jpt/common/utility/internal/command/AbstractSingleUseQueueingCommandExecutor.java | 165 |
1 files changed, 0 insertions, 165 deletions
diff --git a/common/plugins/org.eclipse.jpt.common.utility/src/org/eclipse/jpt/common/utility/internal/command/AbstractSingleUseQueueingCommandExecutor.java b/common/plugins/org.eclipse.jpt.common.utility/src/org/eclipse/jpt/common/utility/internal/command/AbstractSingleUseQueueingCommandExecutor.java deleted file mode 100644 index 19dca1845d..0000000000 --- a/common/plugins/org.eclipse.jpt.common.utility/src/org/eclipse/jpt/common/utility/internal/command/AbstractSingleUseQueueingCommandExecutor.java +++ /dev/null @@ -1,165 +0,0 @@ -/******************************************************************************* - * 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.internal.command; - -import org.eclipse.jpt.common.utility.command.Command; -import org.eclipse.jpt.common.utility.command.StatefulCommandExecutor; -import org.eclipse.jpt.common.utility.internal.SimpleQueue; -import org.eclipse.jpt.common.utility.internal.StringTools; - -/** - * This is a command executor that queues up any commands that are - * {@link #execute(Command) executed} before the executor has been - * {@link #start() started} or while the executor is - * {@link #suspend() suspended}. These commands will be - * executed once the executor is {@link #start() started} or - * {@link #resume() resumed}. Once the executor is {@link #start() started}, - * all commands are executed <em>synchronously</em>. - * Once the executor is {@link #stop() stopped}, no further commands will be - * executed; and the executor can<em>not</em> be {@link #start() restarted}. - */ -public abstract class AbstractSingleUseQueueingCommandExecutor<E extends StatefulCommandExecutor> - implements StatefulCommandExecutor -{ - protected final E commandExecutor; - private State state; - private SimpleQueue<Command> queue = new SimpleQueue<Command>(); - - private enum State { - PRE_START, - ACTIVE, - SUSPENDED, - DEAD - } - - - protected AbstractSingleUseQueueingCommandExecutor(E commandExecutor) { - super(); - if (commandExecutor == null) { - throw new NullPointerException(); - } - this.commandExecutor = commandExecutor; - this.state = State.PRE_START; - } - - /** - * Start the command executor, executing all the commands that were - * queued up since the executor was first constructed. - */ - public synchronized void start() { - if (this.state != State.PRE_START) { - throw this.buildISE(); - } - this.commandExecutor.start(); - while ( ! this.queue.isEmpty()) { - this.commandExecutor.execute(this.queue.dequeue()); - } - this.state = State.ACTIVE; - } - - public void execute(Command command) { - if (this.commandIsToBeExecuted(command)) { - this.commandExecutor.execute(command); - } - } - - /** - * If the command executor is active (i.e. it has been - * {@link #start() started}), execute the specified command. - * If the command executor has not been {@link #start() started} or it is - * {@link #suspend() suspended}, queue the - * command to be executed when the executor is {@link #start() started} or - * {@link #resume() resumed}. - * If the command executor is dead (i.e. it has been - * {@link #stop() stopped}), ignore the command. - */ - private synchronized boolean commandIsToBeExecuted(Command command) { - switch (this.state) { - case ACTIVE: - // execute the command outside the lock - return true; - case PRE_START: - case SUSPENDED: - this.queue.enqueue(command); - return false; - case DEAD: - // ignore - return false; - } - throw this.buildISE(); - } - - /** - * Suspend the command executor. Any further requests to - * {@link #execute(Command) execute} a command will result in the command - * being queued up to be executed once the command executor is - * {@link #resume() resumed}. - */ - public synchronized void suspend() { - if (this.state != State.ACTIVE) { - throw this.buildISE(); - } - this.state = State.SUSPENDED; - } - - /** - * Resume the command executor, executing all the commands that were - * queued up since the executor was {@link #suspend() suspended}. - */ - public synchronized void resume() { - if (this.state != State.SUSPENDED) { - throw this.buildISE(); - } - while ( ! this.queue.isEmpty()) { - this.commandExecutor.execute(this.queue.dequeue()); - } - this.state = State.ACTIVE; - } - - /** - * Stop the command executor. Any queued commands (i.e. the commands - * {@link #execute(Command) executed} while the command executor had not - * been {@link #start() started} or was - * {@link #suspend() suspended}) will be ignored. - * Any further requests to - * {@link #execute(Command) execute} a command will be ignored. - * The command executor <em>cannot</em> be {@link #start() restarted}, - * {@link #suspend() suspended} or {@link #resume() resumed} once it has - * been stopped. - */ - public synchronized void stop() throws InterruptedException { - switch (this.state) { - case ACTIVE: - // nothing to do - break; - case SUSPENDED: - // drain the queue - while ( ! this.queue.isEmpty()) { - this.queue.dequeue(); - } - break; - case PRE_START: - case DEAD: - throw this.buildISE(); - } - - this.commandExecutor.stop(); - this.state = State.DEAD; - } - - private IllegalStateException buildISE() { - return new IllegalStateException(String.valueOf(this.state)); - } - - @Override - public String toString() { - return StringTools.buildToStringFor(this, this.state); - } -} |