/*
* Copyright 2002-2014 the original author or 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 org.springframework.scheduling.concurrent;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.Callable;
import java.util.concurrent.Executor;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Future;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.RejectedExecutionException;
import java.util.concurrent.RejectedExecutionHandler;
import java.util.concurrent.SynchronousQueue;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
import org.springframework.core.task.AsyncListenableTaskExecutor;
import org.springframework.core.task.TaskRejectedException;
import org.springframework.scheduling.SchedulingTaskExecutor;
import org.springframework.util.Assert;
import org.springframework.util.concurrent.ListenableFuture;
import org.springframework.util.concurrent.ListenableFutureTask;
/**
* JavaBean that allows for configuring a {@link java.util.concurrent.ThreadPoolExecutor}
* in bean style (through its "corePoolSize", "maxPoolSize", "keepAliveSeconds", "queueCapacity"
* properties) and exposing it as a Spring {@link org.springframework.core.task.TaskExecutor}.
* This class is also well suited for management and monitoring (e.g. through JMX),
* providing several useful attributes: "corePoolSize", "maxPoolSize", "keepAliveSeconds"
* (all supporting updates at runtime); "poolSize", "activeCount" (for introspection only).
*
* <p>For an alternative, you may set up a ThreadPoolExecutor instance directly using
* constructor injection, or use a factory method definition that points to the
* {@link java.util.concurrent.Executors} class. To expose such a raw Executor as a
* Spring {@link org.springframework.core.task.TaskExecutor}, simply wrap it with a
* {@link org.springframework.scheduling.concurrent.ConcurrentTaskExecutor} adapter.
*
* <p><b>NOTE:</b> This class implements Spring's
* {@link org.springframework.core.task.TaskExecutor} interface as well as the
* {@link java.util.concurrent.Executor} interface, with the former being the primary
* interface, the other just serving as secondary convenience. For this reason, the
* exception handling follows the TaskExecutor contract rather than the Executor contract,
* in particular regarding the {@link org.springframework.core.task.TaskRejectedException}.
*
* <p><b>If you prefer native {@link java.util.concurrent.ExecutorService} exposure instead,
* consider {@link ThreadPoolExecutorFactoryBean} as an alternative to this class.</b>
*
* @author Juergen Hoeller
* @since 2.0
* @see org.springframework.core.task.TaskExecutor
* @see java.util.concurrent.ThreadPoolExecutor
* @see ConcurrentTaskExecutor
*/
@SuppressWarnings("serial")
public class ThreadPoolTaskExecutor extends ExecutorConfigurationSupport
implements AsyncListenableTaskExecutor, SchedulingTaskExecutor {
private final Object poolSizeMonitor = new Object();
private int corePoolSize = 1;
private int maxPoolSize = Integer.MAX_VALUE;
private int keepAliveSeconds = 60;
private int queueCapacity = Integer.MAX_VALUE;
private boolean allowCoreThreadTimeOut = false;
private ThreadPoolExecutor threadPoolExecutor;
/**
* Set the ThreadPoolExecutor's core pool size.
* Default is 1.
* <p><b>This setting can be modified at runtime, for example through JMX.</b>
*/
public void setCorePoolSize(int corePoolSize) {
synchronized (this.poolSizeMonitor) {
this.corePoolSize = corePoolSize;
if (this.threadPoolExecutor != null) {
this.threadPoolExecutor.setCorePoolSize(corePoolSize);
}
}
}
/**
* Return the ThreadPoolExecutor's core pool size.
*/
public int getCorePoolSize() {
synchronized (this.poolSizeMonitor) {
return this.corePoolSize;
}
}
/**
* Set the ThreadPoolExecutor's maximum pool size.
* Default is {@code Integer.MAX_VALUE}.
* <p><b>This setting can be modified at runtime, for example through JMX.</b>
*/
public void setMaxPoolSize(int maxPoolSize) {
synchronized (this.poolSizeMonitor) {
this.maxPoolSize = maxPoolSize;
if (this.threadPoolExecutor != null) {
this.threadPoolExecutor.setMaximumPoolSize(maxPoolSize);
}
}
}
/**
* Return the ThreadPoolExecutor's maximum pool size.
*/
public int getMaxPoolSize() {
synchronized (this.poolSizeMonitor) {
return this.maxPoolSize;
}
}
/**
* Set the ThreadPoolExecutor's keep-alive seconds.
* Default is 60.
* <p><b>This setting can be modified at runtime, for example through JMX.</b>
*/
public void setKeepAliveSeconds(int keepAliveSeconds) {
synchronized (this.poolSizeMonitor) {
this.keepAliveSeconds = keepAliveSeconds;
if (this.threadPoolExecutor != null) {
this.threadPoolExecutor.setKeepAliveTime(keepAliveSeconds, TimeUnit.SECONDS);
}
}
}
/**
* Return the ThreadPoolExecutor's keep-alive seconds.
*/
public int getKeepAliveSeconds() {
synchronized (this.poolSizeMonitor) {
return this.keepAliveSeconds;
}
}
/**
* Set the capacity for the ThreadPoolExecutor's BlockingQueue.
* Default is {@code Integer.MAX_VALUE}.
* <p>Any positive value will lead to a LinkedBlockingQueue instance;
* any other value will lead to a SynchronousQueue instance.
* @see java.util.concurrent.LinkedBlockingQueue
* @see java.util.concurrent.SynchronousQueue
*/
public void setQueueCapacity(int queueCapacity) {
this.queueCapacity = queueCapacity;
}
/**
* Specify whether to allow core threads to time out. This enables dynamic
* growing and shrinking even in combination with a non-zero queue (since
* the max pool size will only grow once the queue is full).
* <p>Default is "false".
* @see java.util.concurrent.ThreadPoolExecutor#allowCoreThreadTimeOut(boolean)
*/
public void setAllowCoreThreadTimeOut(boolean allowCoreThreadTimeOut) {
this.allowCoreThreadTimeOut = allowCoreThreadTimeOut;
}
@Override
protected ExecutorService initializeExecutor(
ThreadFactory threadFactory, RejectedExecutionHandler rejectedExecutionHandler) {
BlockingQueue<Runnable> queue = createQueue(this.queueCapacity);
ThreadPoolExecutor executor = new ThreadPoolExecutor(
this.corePoolSize, this.maxPoolSize, this.keepAliveSeconds, TimeUnit.SECONDS,
queue, threadFactory, rejectedExecutionHandler);
if (this.allowCoreThreadTimeOut) {
executor.allowCoreThreadTimeOut(true);
}
this.threadPoolExecutor = executor;
return executor;
}
/**
* Create the BlockingQueue to use for the ThreadPoolExecutor.
* <p>A LinkedBlockingQueue instance will be created for a positive
* capacity value; a SynchronousQueue else.
* @param queueCapacity the specified queue capacity
* @return the BlockingQueue instance
* @see java.util.concurrent.LinkedBlockingQueue
* @see java.util.concurrent.SynchronousQueue
*/
protected BlockingQueue<Runnable> createQueue(int queueCapacity) {
if (queueCapacity > 0) {
return new LinkedBlockingQueue<Runnable>(queueCapacity);
}
else {
return new SynchronousQueue<Runnable>();
}
}
/**
* Return the underlying ThreadPoolExecutor for native access.
* @return the underlying ThreadPoolExecutor (never {@code null})
* @throws IllegalStateException if the ThreadPoolTaskExecutor hasn't been initialized yet
*/
public ThreadPoolExecutor getThreadPoolExecutor() throws IllegalStateException {
Assert.state(this.threadPoolExecutor != null, "ThreadPoolTaskExecutor not initialized");
return this.threadPoolExecutor;
}
/**
* Return the current pool size.
* @see java.util.concurrent.ThreadPoolExecutor#getPoolSize()
*/
public int getPoolSize() {
if (this.threadPoolExecutor == null) {
// Not initialized yet: assume core pool size.
return this.corePoolSize;
}
return this.threadPoolExecutor.getPoolSize();
}
/**
* Return the number of currently active threads.
* @see java.util.concurrent.ThreadPoolExecutor#getActiveCount()
*/
public int getActiveCount() {
if (this.threadPoolExecutor == null) {
// Not initialized yet: assume no active threads.
return 0;
}
return this.threadPoolExecutor.getActiveCount();
}
@Override
public void execute(Runnable task) {
Executor executor = getThreadPoolExecutor();
try {
executor.execute(task);
}
catch (RejectedExecutionException ex) {
throw new TaskRejectedException("Executor [" + executor + "] did not accept task: " + task, ex);
}
}
@Override
public void execute(Runnable task, long startTimeout) {
execute(task);
}
@Override
public Future<?> submit(Runnable task) {
ExecutorService executor = getThreadPoolExecutor();
try {
return executor.submit(task);
}
catch (RejectedExecutionException ex) {
throw new TaskRejectedException("Executor [" + executor + "] did not accept task: " + task, ex);
}
}
@Override
public <T> Future<T> submit(Callable<T> task) {
ExecutorService executor = getThreadPoolExecutor();
try {
return executor.submit(task);
}
catch (RejectedExecutionException ex) {
throw new TaskRejectedException("Executor [" + executor + "] did not accept task: " + task, ex);
}
}
@Override
public ListenableFuture<?> submitListenable(Runnable task) {
ExecutorService executor = getThreadPoolExecutor();
try {
ListenableFutureTask<Object> future = new ListenableFutureTask<Object>(task, null);
executor.execute(future);
return future;
}
catch (RejectedExecutionException ex) {
throw new TaskRejectedException("Executor [" + executor + "] did not accept task: " + task, ex);
}
}
@Override
public <T> ListenableFuture<T> submitListenable(Callable<T> task) {
ExecutorService executor = getThreadPoolExecutor();
try {
ListenableFutureTask<T> future = new ListenableFutureTask<T>(task);
executor.execute(future);
return future;
}
catch (RejectedExecutionException ex) {
throw new TaskRejectedException("Executor [" + executor + "] did not accept task: " + task, ex);
}
}
/**
* This task executor prefers short-lived work units.
*/
@Override
public boolean prefersShortLivedTasks() {
return true;
}
}