org.jboss.netty.util.internal.ExecutorUtil Maven / Gradle / Ivy
/*
* Copyright 2012 The Netty Project
*
* The Netty Project licenses this file to you 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 org.jboss.netty.util.internal;
import java.util.concurrent.Executor;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.TimeUnit;
/**
* Shuts down a list of {@link Executor}s. {@link #terminate(Executor...)} will
* shut down all specified {@link ExecutorService}s immediately and wait for
* their termination. An {@link Executor} which is not an {@link ExecutorService}
* will be ignored silently.
*/
public final class ExecutorUtil {
/**
* Try to call {@link ExecutorService#shutdownNow()}
*/
public static void shutdownNow(Executor executor) {
if (executor instanceof ExecutorService) {
ExecutorService es = (ExecutorService) executor;
try {
es.shutdownNow();
} catch (SecurityException ex) {
// Running in a restricted environment - fall back.
try {
es.shutdown();
} catch (SecurityException ex2) {
// Running in a more restricted environment.
// Can't shut down this executor - skip to the next.
} catch (NullPointerException ex2) {
// Some JDK throws NPE here, but shouldn't.
}
} catch (NullPointerException ex) {
// Some JDK throws NPE here, but shouldn't.
}
}
}
/**
* Returns {@code true} if and only if the specified {@code executor}
* is an {@link ExecutorService} and is shut down. Please note that this
* method returns {@code false} if the specified {@code executor} is not an
* {@link ExecutorService}.
*/
public static boolean isShutdown(Executor executor) {
if (executor instanceof ExecutorService) {
if (((ExecutorService) executor).isShutdown()) {
return true;
}
}
return false;
}
/**
* Shuts down the specified executors.
*/
public static void terminate(Executor... executors) {
terminate(DeadLockProofWorker.PARENT, executors);
}
/**
* Shuts down the specified executors using the given {@link ThreadLocal} to check if there is a deadlock
*/
public static void terminate(ThreadLocal deadLockChecker, Executor... executors) {
// Check nulls.
if (executors == null) {
throw new NullPointerException("executors");
}
Executor[] executorsCopy = new Executor[executors.length];
for (int i = 0; i < executors.length; i ++) {
if (executors[i] == null) {
throw new NullPointerException("executors[" + i + ']');
}
executorsCopy[i] = executors[i];
}
// Check dead lock.
final Executor currentParent = deadLockChecker.get();
if (currentParent != null) {
for (Executor e: executorsCopy) {
if (e == currentParent) {
throw new IllegalStateException(
"An Executor cannot be shut down from the thread " +
"acquired from itself. Please make sure you are " +
"not calling releaseExternalResources() from an " +
"I/O worker thread.");
}
}
}
// Shut down all executors.
boolean interrupted = false;
for (Executor e: executorsCopy) {
if (!(e instanceof ExecutorService)) {
continue;
}
ExecutorService es = (ExecutorService) e;
for (;;) {
shutdownNow(es);
try {
if (es.awaitTermination(100, TimeUnit.MILLISECONDS)) {
break;
}
} catch (InterruptedException ex) {
interrupted = true;
}
}
}
if (interrupted) {
Thread.currentThread().interrupt();
}
}
private ExecutorUtil() {
}
}