/*
* Copyright 2002-2009 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.TaskRejectedException;
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.ErrorHandler;
/**
* 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 #setThreadFactory
* @see #setErrorHandler
*/
public class ThreadPoolTaskScheduler extends ExecutorConfigurationSupport
implements TaskScheduler, SchedulingTaskExecutor {
private volatile int poolSize = 1;
private volatile ScheduledExecutorService scheduledExecutor;
private volatile ErrorHandler errorHandler;
/**
* Set the ScheduledExecutorService's pool size.
* Default is 1.
*/
public void setPoolSize(int poolSize) {
Assert.isTrue(poolSize > 0, "'poolSize' must be 1 or higher");
this.poolSize = poolSize;
}
/**
* Provide an {@link ErrorHandler} strategy.
*/
public void setErrorHandler(ErrorHandler errorHandler) {
Assert.notNull(errorHandler, "'errorHandler' must not be null");
this.errorHandler = errorHandler;
}
protected ExecutorService initializeExecutor(
ThreadFactory threadFactory, RejectedExecutionHandler rejectedExecutionHandler) {
this.scheduledExecutor = createExecutor(this.poolSize, threadFactory, rejectedExecutionHandler);
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</code>)
* @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;
}
// SchedulingTaskExecutor implementation
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);
}
}
public void execute(Runnable task, long startTimeout) {
execute(task);
}
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);
}
}
public <T> Future<T> submit(Callable<T> task) {
ExecutorService executor = getScheduledExecutor();
try {
if (this.errorHandler != null) {
task = new DelegatingErrorHandlingCallable<T>(task, this.errorHandler);
}
return executor.submit(task);
}
catch (RejectedExecutionException ex) {
throw new TaskRejectedException("Executor [" + executor + "] did not accept task: " + task, ex);
}
}
public boolean prefersShortLivedTasks() {
return true;
}
// TaskScheduler implementation
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);
}
}
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);
}
}
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);
}
}
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);
}
}
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);
}
}
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;
DelegatingErrorHandlingCallable(Callable<V> delegate, ErrorHandler errorHandler) {
this.delegate = delegate;
this.errorHandler = errorHandler;
}
public V call() throws Exception {
try {
return delegate.call();
}
catch (Throwable t) {
this.errorHandler.handleError(t);
return null;
}
}
}
}