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/*
* 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.ListeningScheduledExecutorService;
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.
*
* 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();
}
private static final class NoOpScheduledExecutorService
extends AbstractListeningExecutorService implements ListeningScheduledExecutorService {
private volatile boolean shutdown;
@Override public void shutdown() {
shutdown = true;
}
@Override public List 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 ScheduledFuture schedule(
Callable callable, long delay, TimeUnit unit) {
return NeverScheduledFuture.create();
}
@Override public ScheduledFuture schedule(Runnable command, long delay, TimeUnit unit) {
return NeverScheduledFuture.create();
}
@Override public ScheduledFuture scheduleAtFixedRate(
Runnable command, long initialDelay, long period, TimeUnit unit) {
return NeverScheduledFuture.create();
}
@Override public ScheduledFuture scheduleWithFixedDelay(
Runnable command, long initialDelay, long delay, TimeUnit unit) {
return NeverScheduledFuture.create();
}
private static class NeverScheduledFuture
extends AbstractFuture implements ScheduledFuture {
static NeverScheduledFuture create() {
return new NeverScheduledFuture();
}
@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));
}
}
}
}