| /* |
| * Copyright (C) 2012 The Guava Authors |
| * |
| * 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.testing; |
| |
| import com.google.common.annotations.Beta; |
| import com.google.common.collect.ImmutableList; |
| import com.google.common.primitives.Longs; |
| import com.google.common.util.concurrent.AbstractFuture; |
| import com.google.common.util.concurrent.AbstractListeningExecutorService; |
| import com.google.common.util.concurrent.ListenableScheduledFuture; |
| import com.google.common.util.concurrent.ListeningScheduledExecutorService; |
| import com.google.common.util.concurrent.MoreExecutors; |
| |
| import java.util.List; |
| import java.util.concurrent.Callable; |
| import java.util.concurrent.Delayed; |
| import java.util.concurrent.ScheduledFuture; |
| import java.util.concurrent.TimeUnit; |
| |
| /** |
| * Factory methods for {@link ExecutorService} for testing. |
| * |
| * @author Chris Nokleberg |
| * @since 14.0 |
| */ |
| @Beta |
| public final class TestingExecutors { |
| private TestingExecutors() {} |
| |
| /** |
| * Returns a {@link ScheduledExecutorService} that never executes anything. |
| * |
| * <p>The {@code shutdownNow} method of the returned executor always returns an empty list despite |
| * the fact that everything is still technically awaiting execution. |
| * The {@code getDelay} method of any {@link ScheduledFuture} returned by the executor will always |
| * return the max long value instead of the time until the user-specified delay. |
| */ |
| public static ListeningScheduledExecutorService noOpScheduledExecutor() { |
| return new NoOpScheduledExecutorService(); |
| } |
| |
| /** |
| * Creates a scheduled executor service that runs each task in the thread |
| * that invokes {@code execute/submit/schedule}, as in |
| * {@link CallerRunsPolicy}. This applies both to individually submitted |
| * tasks and to collections of tasks submitted via {@code invokeAll}, |
| * {@code invokeAny}, {@code schedule}, {@code scheduleAtFixedRate}, and |
| * {@code scheduleWithFixedDelay}. In the case of tasks submitted by |
| * {@code invokeAll} or {@code invokeAny}, tasks will run serially on the |
| * calling thread. Tasks are run to completion before a {@code Future} is |
| * returned to the caller (unless the executor has been shutdown). |
| * |
| * <p>The returned executor is backed by the executor returned by |
| * {@link MoreExecutors#newDirectExecutorService} and subject to the same |
| * constraints. |
| * |
| * <p>Although all tasks are immediately executed in the thread that |
| * submitted the task, this {@code ExecutorService} imposes a small |
| * locking overhead on each task submission in order to implement shutdown |
| * and termination behavior. |
| * |
| * <p>Because of the nature of single-thread execution, the methods |
| * {@code scheduleAtFixedRate} and {@code scheduleWithFixedDelay} are not |
| * supported by this class and will throw an UnsupportedOperationException. |
| * |
| * <p>The implementation deviates from the {@code ExecutorService} |
| * specification with regards to the {@code shutdownNow} method. First, |
| * "best-effort" with regards to canceling running tasks is implemented |
| * as "no-effort". No interrupts or other attempts are made to stop |
| * threads executing tasks. Second, the returned list will always be empty, |
| * as any submitted task is considered to have started execution. |
| * This applies also to tasks given to {@code invokeAll} or {@code invokeAny} |
| * which are pending serial execution, even the subset of the tasks that |
| * have not yet started execution. It is unclear from the |
| * {@code ExecutorService} specification if these should be included, and |
| * it's much easier to implement the interpretation that they not be. |
| * Finally, a call to {@code shutdown} or {@code shutdownNow} may result |
| * in concurrent calls to {@code invokeAll/invokeAny} throwing |
| * RejectedExecutionException, although a subset of the tasks may already |
| * have been executed. |
| * |
| * @since 15.0 |
| */ |
| public static SameThreadScheduledExecutorService sameThreadScheduledExecutor() { |
| return new SameThreadScheduledExecutorService(); |
| } |
| |
| private static final class NoOpScheduledExecutorService |
| extends AbstractListeningExecutorService implements ListeningScheduledExecutorService { |
| |
| private volatile boolean shutdown; |
| |
| @Override public void shutdown() { |
| shutdown = true; |
| } |
| |
| @Override public List<Runnable> shutdownNow() { |
| shutdown(); |
| return ImmutableList.of(); |
| } |
| |
| @Override public boolean isShutdown() { |
| return shutdown; |
| } |
| |
| @Override public boolean isTerminated() { |
| return shutdown; |
| } |
| |
| @Override public boolean awaitTermination(long timeout, TimeUnit unit) { |
| return true; |
| } |
| |
| @Override public void execute(Runnable runnable) {} |
| |
| @Override public <V> ListenableScheduledFuture<V> schedule( |
| Callable<V> callable, long delay, TimeUnit unit) { |
| return NeverScheduledFuture.create(); |
| } |
| |
| @Override public ListenableScheduledFuture<?> schedule( |
| Runnable command, long delay, TimeUnit unit) { |
| return NeverScheduledFuture.create(); |
| } |
| |
| @Override public ListenableScheduledFuture<?> scheduleAtFixedRate( |
| Runnable command, long initialDelay, long period, TimeUnit unit) { |
| return NeverScheduledFuture.create(); |
| } |
| |
| @Override public ListenableScheduledFuture<?> scheduleWithFixedDelay( |
| Runnable command, long initialDelay, long delay, TimeUnit unit) { |
| return NeverScheduledFuture.create(); |
| } |
| |
| private static class NeverScheduledFuture<V> |
| extends AbstractFuture<V> implements ListenableScheduledFuture<V> { |
| |
| static <V> NeverScheduledFuture<V> create() { |
| return new NeverScheduledFuture<V>(); |
| } |
| |
| @Override public long getDelay(TimeUnit unit) { |
| return Long.MAX_VALUE; |
| } |
| |
| @Override public int compareTo(Delayed other) { |
| return Longs.compare(getDelay(TimeUnit.NANOSECONDS), other.getDelay(TimeUnit.NANOSECONDS)); |
| } |
| } |
| } |
| } |