/*
* 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.Date;
import java.util.concurrent.Callable;
import java.util.concurrent.Executor;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Future;
import java.util.concurrent.RejectedExecutionException;
import java.util.concurrent.RejectedExecutionHandler;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.ScheduledThreadPoolExecutor;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.TimeUnit;
import org.springframework.core.task.AsyncListenableTaskExecutor;
import org.springframework.core.task.TaskRejectedException;
import org.springframework.lang.UsesJava7;
import org.springframework.scheduling.SchedulingTaskExecutor;
import org.springframework.scheduling.TaskScheduler;
import org.springframework.scheduling.Trigger;
import org.springframework.scheduling.support.TaskUtils;
import org.springframework.util.Assert;
import org.springframework.util.ClassUtils;
import org.springframework.util.ErrorHandler;
import org.springframework.util.concurrent.ListenableFuture;
import org.springframework.util.concurrent.ListenableFutureTask;
/**
* Implementation of Spring's {@link TaskScheduler} interface, wrapping
* a native {@link java.util.concurrent.ScheduledThreadPoolExecutor}.
*
* @author Juergen Hoeller
* @author Mark Fisher
* @since 3.0
* @see #setPoolSize
* @see #setRemoveOnCancelPolicy
* @see #setThreadFactory
* @see #setErrorHandler
*/
@SuppressWarnings("serial")
public class ThreadPoolTaskScheduler extends ExecutorConfigurationSupport
implements AsyncListenableTaskExecutor, SchedulingTaskExecutor, TaskScheduler {
// ScheduledThreadPoolExecutor.setRemoveOnCancelPolicy(boolean) only available on JDK 7+
private static final boolean setRemoveOnCancelPolicyAvailable =
ClassUtils.hasMethod(ScheduledThreadPoolExecutor.class, "setRemoveOnCancelPolicy", boolean.class);
private volatile int poolSize = 1;
private volatile boolean removeOnCancelPolicy = false;
private volatile ScheduledExecutorService scheduledExecutor;
private volatile ErrorHandler errorHandler;
/**
* Set the ScheduledExecutorService's pool size.
* Default is 1.
* <p><b>This setting can be modified at runtime, for example through JMX.</b>
*/
public void setPoolSize(int poolSize) {
Assert.isTrue(poolSize > 0, "'poolSize' must be 1 or higher");
this.poolSize = poolSize;
if (this.scheduledExecutor instanceof ScheduledThreadPoolExecutor) {
((ScheduledThreadPoolExecutor) this.scheduledExecutor).setCorePoolSize(poolSize);
}
}
/**
* Set the remove-on-cancel mode on {@link ScheduledThreadPoolExecutor} (JDK 7+).
* <p>Default is {@code false}. If set to {@code true}, the target executor will be
* switched into remove-on-cancel mode (if possible, with a soft fallback otherwise).
* <p><b>This setting can be modified at runtime, for example through JMX.</b>
*/
@UsesJava7
public void setRemoveOnCancelPolicy(boolean removeOnCancelPolicy) {
this.removeOnCancelPolicy = removeOnCancelPolicy;
if (setRemoveOnCancelPolicyAvailable && this.scheduledExecutor instanceof ScheduledThreadPoolExecutor) {
((ScheduledThreadPoolExecutor) this.scheduledExecutor).setRemoveOnCancelPolicy(removeOnCancelPolicy);
}
else if (removeOnCancelPolicy && this.scheduledExecutor != null) {
logger.info("Could not apply remove-on-cancel policy - not a Java 7+ ScheduledThreadPoolExecutor");
}
}
/**
* Set a custom {@link ErrorHandler} strategy.
*/
public void setErrorHandler(ErrorHandler errorHandler) {
this.errorHandler = errorHandler;
}
@UsesJava7
@Override
protected ExecutorService initializeExecutor(
ThreadFactory threadFactory, RejectedExecutionHandler rejectedExecutionHandler) {
this.scheduledExecutor = createExecutor(this.poolSize, threadFactory, rejectedExecutionHandler);
if (this.removeOnCancelPolicy) {
if (setRemoveOnCancelPolicyAvailable && this.scheduledExecutor instanceof ScheduledThreadPoolExecutor) {
((ScheduledThreadPoolExecutor) this.scheduledExecutor).setRemoveOnCancelPolicy(true);
}
else {
logger.info("Could not apply remove-on-cancel policy - not a Java 7+ ScheduledThreadPoolExecutor");
}
}
return this.scheduledExecutor;
}
/**
* Create a new {@link ScheduledExecutorService} instance.
* <p>The default implementation creates a {@link ScheduledThreadPoolExecutor}.
* Can be overridden in subclasses to provide custom {@link ScheduledExecutorService} instances.
* @param poolSize the specified pool size
* @param threadFactory the ThreadFactory to use
* @param rejectedExecutionHandler the RejectedExecutionHandler to use
* @return a new ScheduledExecutorService instance
* @see #afterPropertiesSet()
* @see java.util.concurrent.ScheduledThreadPoolExecutor
*/
protected ScheduledExecutorService createExecutor(
int poolSize, ThreadFactory threadFactory, RejectedExecutionHandler rejectedExecutionHandler) {
return new ScheduledThreadPoolExecutor(poolSize, threadFactory, rejectedExecutionHandler);
}
/**
* Return the underlying ScheduledExecutorService for native access.
* @return the underlying ScheduledExecutorService (never {@code null})
* @throws IllegalStateException if the ThreadPoolTaskScheduler hasn't been initialized yet
*/
public ScheduledExecutorService getScheduledExecutor() throws IllegalStateException {
Assert.state(this.scheduledExecutor != null, "ThreadPoolTaskScheduler not initialized");
return this.scheduledExecutor;
}
/**
* Return the underlying ScheduledThreadPoolExecutor, if available.
* @return the underlying ScheduledExecutorService (never {@code null})
* @throws IllegalStateException if the ThreadPoolTaskScheduler hasn't been initialized yet
* or if the underlying ScheduledExecutorService isn't a ScheduledThreadPoolExecutor
* @see #getScheduledExecutor()
*/
public ScheduledThreadPoolExecutor getScheduledThreadPoolExecutor() throws IllegalStateException {
Assert.state(this.scheduledExecutor instanceof ScheduledThreadPoolExecutor,
"No ScheduledThreadPoolExecutor available");
return (ScheduledThreadPoolExecutor) this.scheduledExecutor;
}
/**
* Return the current pool size.
* <p>Requires an underlying {@link ScheduledThreadPoolExecutor}.
* @see #getScheduledThreadPoolExecutor()
* @see java.util.concurrent.ScheduledThreadPoolExecutor#getPoolSize()
*/
public int getPoolSize() {
if (this.scheduledExecutor == null) {
// Not initialized yet: assume initial pool size.
return this.poolSize;
}
return getScheduledThreadPoolExecutor().getPoolSize();
}
/**
* Return the current setting for the remove-on-cancel mode.
* <p>Requires an underlying {@link ScheduledThreadPoolExecutor}.
*/
@UsesJava7
public boolean isRemoveOnCancelPolicy() {
if (!setRemoveOnCancelPolicyAvailable) {
return false;
}
if (this.scheduledExecutor == null) {
// Not initialized yet: return our setting for the time being.
return this.removeOnCancelPolicy;
}
return getScheduledThreadPoolExecutor().getRemoveOnCancelPolicy();
}
/**
* Return the number of currently active threads.
* <p>Requires an underlying {@link ScheduledThreadPoolExecutor}.
* @see #getScheduledThreadPoolExecutor()
* @see java.util.concurrent.ScheduledThreadPoolExecutor#getActiveCount()
*/
public int getActiveCount() {
if (this.scheduledExecutor == null) {
// Not initialized yet: assume no active threads.
return 0;
}
return getScheduledThreadPoolExecutor().getActiveCount();
}
// SchedulingTaskExecutor implementation
@Override
public void execute(Runnable task) {
Executor executor = getScheduledExecutor();
try {
executor.execute(errorHandlingTask(task, false));
}
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 = getScheduledExecutor();
try {
return executor.submit(errorHandlingTask(task, false));
}
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 = getScheduledExecutor();
try {
Callable<T> taskToUse = task;
if (this.errorHandler != null) {
taskToUse = new DelegatingErrorHandlingCallable<T>(task, this.errorHandler);
}
return executor.submit(taskToUse);
}
catch (RejectedExecutionException ex) {
throw new TaskRejectedException("Executor [" + executor + "] did not accept task: " + task, ex);
}
}
@Override
public ListenableFuture<?> submitListenable(Runnable task) {
ExecutorService executor = getScheduledExecutor();
try {
ListenableFutureTask<Object> future = new ListenableFutureTask<Object>(task, null);
executor.execute(errorHandlingTask(future, false));
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 = getScheduledExecutor();
try {
ListenableFutureTask<T> future = new ListenableFutureTask<T>(task);
executor.execute(errorHandlingTask(future, false));
return future;
}
catch (RejectedExecutionException ex) {
throw new TaskRejectedException("Executor [" + executor + "] did not accept task: " + task, ex);
}
}
@Override
public boolean prefersShortLivedTasks() {
return true;
}
// TaskScheduler implementation
@Override
public ScheduledFuture<?> schedule(Runnable task, Trigger trigger) {
ScheduledExecutorService executor = getScheduledExecutor();
try {
ErrorHandler errorHandler =
(this.errorHandler != null ? this.errorHandler : TaskUtils.getDefaultErrorHandler(true));
return new ReschedulingRunnable(task, trigger, executor, errorHandler).schedule();
}
catch (RejectedExecutionException ex) {
throw new TaskRejectedException("Executor [" + executor + "] did not accept task: " + task, ex);
}
}
@Override
public ScheduledFuture<?> schedule(Runnable task, Date startTime) {
ScheduledExecutorService executor = getScheduledExecutor();
long initialDelay = startTime.getTime() - System.currentTimeMillis();
try {
return executor.schedule(errorHandlingTask(task, false), initialDelay, TimeUnit.MILLISECONDS);
}
catch (RejectedExecutionException ex) {
throw new TaskRejectedException("Executor [" + executor + "] did not accept task: " + task, ex);
}
}
@Override
public ScheduledFuture<?> scheduleAtFixedRate(Runnable task, Date startTime, long period) {
ScheduledExecutorService executor = getScheduledExecutor();
long initialDelay = startTime.getTime() - System.currentTimeMillis();
try {
return executor.scheduleAtFixedRate(errorHandlingTask(task, true), initialDelay, period, TimeUnit.MILLISECONDS);
}
catch (RejectedExecutionException ex) {
throw new TaskRejectedException("Executor [" + executor + "] did not accept task: " + task, ex);
}
}
@Override
public ScheduledFuture<?> scheduleAtFixedRate(Runnable task, long period) {
ScheduledExecutorService executor = getScheduledExecutor();
try {
return executor.scheduleAtFixedRate(errorHandlingTask(task, true), 0, period, TimeUnit.MILLISECONDS);
}
catch (RejectedExecutionException ex) {
throw new TaskRejectedException("Executor [" + executor + "] did not accept task: " + task, ex);
}
}
@Override
public ScheduledFuture<?> scheduleWithFixedDelay(Runnable task, Date startTime, long delay) {
ScheduledExecutorService executor = getScheduledExecutor();
long initialDelay = startTime.getTime() - System.currentTimeMillis();
try {
return executor.scheduleWithFixedDelay(errorHandlingTask(task, true), initialDelay, delay, TimeUnit.MILLISECONDS);
}
catch (RejectedExecutionException ex) {
throw new TaskRejectedException("Executor [" + executor + "] did not accept task: " + task, ex);
}
}
@Override
public ScheduledFuture<?> scheduleWithFixedDelay(Runnable task, long delay) {
ScheduledExecutorService executor = getScheduledExecutor();
try {
return executor.scheduleWithFixedDelay(errorHandlingTask(task, true), 0, delay, TimeUnit.MILLISECONDS);
}
catch (RejectedExecutionException ex) {
throw new TaskRejectedException("Executor [" + executor + "] did not accept task: " + task, ex);
}
}
private Runnable errorHandlingTask(Runnable task, boolean isRepeatingTask) {
return TaskUtils.decorateTaskWithErrorHandler(task, this.errorHandler, isRepeatingTask);
}
private static class DelegatingErrorHandlingCallable<V> implements Callable<V> {
private final Callable<V> delegate;
private final ErrorHandler errorHandler;
public DelegatingErrorHandlingCallable(Callable<V> delegate, ErrorHandler errorHandler) {
this.delegate = delegate;
this.errorHandler = errorHandler;
}
@Override
public V call() throws Exception {
try {
return this.delegate.call();
}
catch (Throwable t) {
this.errorHandler.handleError(t);
return null;
}
}
}
}