All Downloads are FREE. Search and download functionalities are using the official Maven repository.

com.google.common.util.concurrent.WrappingExecutorService Maven / Gradle / Ivy

Go to download 

/*
 * Original Guava code is copyright (C) 2015 The Guava Authors.
 * Modifications from Guava are copyright (C) 2015 DiffPlug.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.google.common.util.concurrent;

import static com.google.common.base.Preconditions.checkNotNull;

import java.util.Collection;
import java.util.List;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;

import com.google.common.base.Throwables;
import com.google.common.collect.ImmutableList;

/**
 * An abstract {@code ExecutorService} that allows subclasses to
 * {@linkplain #wrapTask(Callable) wrap} tasks before they are submitted
 * to the underlying executor.
 *
 * 
Note that task wrapping may occur even if the task is never executed.
 *
 * 
For delegation without task-wrapping, see
 * {@link ForwardingExecutorService}.
 *
 * @author Chris Nokleberg
 */
abstract class WrappingExecutorService implements ExecutorService {
	private final ExecutorService delegate;

	protected WrappingExecutorService(ExecutorService delegate) {
		this.delegate = checkNotNull(delegate);
	}

	/**
	 * Wraps a {@code Callable} for submission to the underlying executor. This
	 * method is also applied to any {@code Runnable} passed to the default
	 * implementation of {@link #wrapTask(Runnable)}.
	 */
	protected abstract  Callable wrapTask(Callable callable);

	/**
	 * Wraps a {@code Runnable} for submission to the underlying executor. The
	 * default implementation delegates to {@link #wrapTask(Callable)}.
	 */
	protected Runnable wrapTask(Runnable command) {
		final Callable wrapped = wrapTask(
				Executors.callable(command, null));
		return new Runnable() {
			@Override
			public void run() {
				try {
					wrapped.call();
				} catch (Exception e) {
					Throwables.propagate(e);
				}
			}
		};
	}

	/**
	 * Wraps a collection of tasks.
	 *
	 * @throws NullPointerException if any element of {@code tasks} is null
	 */
	private final  ImmutableList> wrapTasks(
			Collection> tasks) {
		ImmutableList.Builder> builder = ImmutableList.builder();
		for (Callable task : tasks) {
			builder.add(wrapTask(task));
		}
		return builder.build();
	}

	// These methods wrap before delegating.
	@Override
	public final void execute(Runnable command) {
		delegate.execute(wrapTask(command));
	}

	@Override
	public final  Future submit(Callable task) {
		return delegate.submit(wrapTask(checkNotNull(task)));
	}

	@Override
	public final Future submit(Runnable task) {
		return delegate.submit(wrapTask(task));
	}

	@Override
	public final  Future submit(Runnable task, T result) {
		return delegate.submit(wrapTask(task), result);
	}

	@Override
	public final  List> invokeAll(
			Collection> tasks) throws InterruptedException {
		return delegate.invokeAll(wrapTasks(tasks));
	}

	@Override
	public final  List> invokeAll(
			Collection> tasks, long timeout, TimeUnit unit)
					throws InterruptedException {
		return delegate.invokeAll(wrapTasks(tasks), timeout, unit);
	}

	@Override
	public final  T invokeAny(Collection> tasks)
			throws InterruptedException, ExecutionException {
		return delegate.invokeAny(wrapTasks(tasks));
	}

	@Override
	public final  T invokeAny(
			Collection> tasks, long timeout, TimeUnit unit)
					throws InterruptedException, ExecutionException, TimeoutException {
		return delegate.invokeAny(wrapTasks(tasks), timeout, unit);
	}

	// The remaining methods just delegate.

	@Override
	public final void shutdown() {
		delegate.shutdown();
	}

	@Override
	public final List shutdownNow() {
		return delegate.shutdownNow();
	}

	@Override
	public final boolean isShutdown() {
		return delegate.isShutdown();
	}

	@Override
	public final boolean isTerminated() {
		return delegate.isTerminated();
	}

	@Override
	public final boolean awaitTermination(long timeout, TimeUnit unit)
			throws InterruptedException {
		return delegate.awaitTermination(timeout, unit);
	}
}
    

    

    

            

    

            



    
    






    
© 2015 - 2024 Weber Informatics LLC | Privacy Policy