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/*
* 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.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.RejectedExecutionHandler;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledThreadPoolExecutor;
import java.util.concurrent.ThreadFactory;
import org.springframework.beans.factory.FactoryBean;
import org.springframework.lang.UsesJava7;
import org.springframework.scheduling.support.DelegatingErrorHandlingRunnable;
import org.springframework.scheduling.support.TaskUtils;
import org.springframework.util.Assert;
import org.springframework.util.ClassUtils;
import org.springframework.util.ObjectUtils;
/**
* {@link org.springframework.beans.factory.FactoryBean} that sets up
* a {@link java.util.concurrent.ScheduledExecutorService}
* (by default: a {@link java.util.concurrent.ScheduledThreadPoolExecutor})
* and exposes it for bean references.
*
* Allows for registration of {@link ScheduledExecutorTask ScheduledExecutorTasks},
* automatically starting the {@link ScheduledExecutorService} on initialization and
* cancelling it on destruction of the context. In scenarios that only require static
* registration of tasks at startup, there is no need to access the
* {@link ScheduledExecutorService} instance itself in application code at all;
* ScheduledExecutorFactoryBean is then just being used for lifecycle integration.
*
*
Note that {@link java.util.concurrent.ScheduledExecutorService}
* uses a {@link Runnable} instance that is shared between repeated executions,
* in contrast to Quartz which instantiates a new Job for each execution.
*
*
WARNING: {@link Runnable Runnables} submitted via a native
* {@link java.util.concurrent.ScheduledExecutorService} are removed from
* the execution schedule once they throw an exception. If you would prefer
* to continue execution after such an exception, switch this FactoryBean's
* {@link #setContinueScheduledExecutionAfterException "continueScheduledExecutionAfterException"}
* property to "true".
*
* @author Juergen Hoeller
* @since 2.0
* @see #setPoolSize
* @see #setRemoveOnCancelPolicy
* @see #setThreadFactory
* @see ScheduledExecutorTask
* @see java.util.concurrent.ScheduledExecutorService
* @see java.util.concurrent.ScheduledThreadPoolExecutor
*/
@SuppressWarnings("serial")
public class ScheduledExecutorFactoryBean extends ExecutorConfigurationSupport
implements FactoryBean {
// ScheduledThreadPoolExecutor.setRemoveOnCancelPolicy(boolean) only available on JDK 7+
private static final boolean setRemoveOnCancelPolicyAvailable =
ClassUtils.hasMethod(ScheduledThreadPoolExecutor.class, "setRemoveOnCancelPolicy", boolean.class);
private int poolSize = 1;
private ScheduledExecutorTask[] scheduledExecutorTasks;
private boolean removeOnCancelPolicy = false;
private boolean continueScheduledExecutionAfterException = false;
private boolean exposeUnconfigurableExecutor = false;
private ScheduledExecutorService exposedExecutor;
/**
* 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;
}
/**
* Register a list of ScheduledExecutorTask objects with the ScheduledExecutorService
* that this FactoryBean creates. Depending on each ScheduledExecutorTask's settings,
* it will be registered via one of ScheduledExecutorService's schedule methods.
* @see java.util.concurrent.ScheduledExecutorService#schedule(java.lang.Runnable, long, java.util.concurrent.TimeUnit)
* @see java.util.concurrent.ScheduledExecutorService#scheduleWithFixedDelay(java.lang.Runnable, long, long, java.util.concurrent.TimeUnit)
* @see java.util.concurrent.ScheduledExecutorService#scheduleAtFixedRate(java.lang.Runnable, long, long, java.util.concurrent.TimeUnit)
*/
public void setScheduledExecutorTasks(ScheduledExecutorTask... scheduledExecutorTasks) {
this.scheduledExecutorTasks = scheduledExecutorTasks;
}
/**
* Set the remove-on-cancel mode on {@link ScheduledThreadPoolExecutor} (JDK 7+).
* 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).
*/
public void setRemoveOnCancelPolicy(boolean removeOnCancelPolicy) {
this.removeOnCancelPolicy = removeOnCancelPolicy;
}
/**
* Specify whether to continue the execution of a scheduled task
* after it threw an exception.
*
Default is "false", matching the native behavior of a
* {@link java.util.concurrent.ScheduledExecutorService}.
* Switch this flag to "true" for exception-proof execution of each task,
* continuing scheduled execution as in the case of successful execution.
* @see java.util.concurrent.ScheduledExecutorService#scheduleAtFixedRate
*/
public void setContinueScheduledExecutionAfterException(boolean continueScheduledExecutionAfterException) {
this.continueScheduledExecutionAfterException = continueScheduledExecutionAfterException;
}
/**
* Specify whether this FactoryBean should expose an unconfigurable
* decorator for the created executor.
*
Default is "false", exposing the raw executor as bean reference.
* Switch this flag to "true" to strictly prevent clients from
* modifying the executor's configuration.
* @see java.util.concurrent.Executors#unconfigurableScheduledExecutorService
*/
public void setExposeUnconfigurableExecutor(boolean exposeUnconfigurableExecutor) {
this.exposeUnconfigurableExecutor = exposeUnconfigurableExecutor;
}
@Override
@UsesJava7
protected ExecutorService initializeExecutor(
ThreadFactory threadFactory, RejectedExecutionHandler rejectedExecutionHandler) {
ScheduledExecutorService executor =
createExecutor(this.poolSize, threadFactory, rejectedExecutionHandler);
if (this.removeOnCancelPolicy) {
if (setRemoveOnCancelPolicyAvailable && executor instanceof ScheduledThreadPoolExecutor) {
((ScheduledThreadPoolExecutor) executor).setRemoveOnCancelPolicy(true);
}
else {
logger.info("Could not apply remove-on-cancel policy - not a Java 7+ ScheduledThreadPoolExecutor");
}
}
// Register specified ScheduledExecutorTasks, if necessary.
if (!ObjectUtils.isEmpty(this.scheduledExecutorTasks)) {
registerTasks(this.scheduledExecutorTasks, executor);
}
// Wrap executor with an unconfigurable decorator.
this.exposedExecutor = (this.exposeUnconfigurableExecutor ?
Executors.unconfigurableScheduledExecutorService(executor) : executor);
return executor;
}
/**
* Create a new {@link ScheduledExecutorService} instance.
*
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);
}
/**
* Register the specified {@link ScheduledExecutorTask ScheduledExecutorTasks}
* on the given {@link ScheduledExecutorService}.
* @param tasks the specified ScheduledExecutorTasks (never empty)
* @param executor the ScheduledExecutorService to register the tasks on.
*/
protected void registerTasks(ScheduledExecutorTask[] tasks, ScheduledExecutorService executor) {
for (ScheduledExecutorTask task : tasks) {
Runnable runnable = getRunnableToSchedule(task);
if (task.isOneTimeTask()) {
executor.schedule(runnable, task.getDelay(), task.getTimeUnit());
}
else {
if (task.isFixedRate()) {
executor.scheduleAtFixedRate(runnable, task.getDelay(), task.getPeriod(), task.getTimeUnit());
}
else {
executor.scheduleWithFixedDelay(runnable, task.getDelay(), task.getPeriod(), task.getTimeUnit());
}
}
}
}
/**
* Determine the actual Runnable to schedule for the given task.
*
Wraps the task's Runnable in a
* {@link org.springframework.scheduling.support.DelegatingErrorHandlingRunnable}
* that will catch and log the Exception. If necessary, it will suppress the
* Exception according to the
* {@link #setContinueScheduledExecutionAfterException "continueScheduledExecutionAfterException"}
* flag.
* @param task the ScheduledExecutorTask to schedule
* @return the actual Runnable to schedule (may be a decorator)
*/
protected Runnable getRunnableToSchedule(ScheduledExecutorTask task) {
return (this.continueScheduledExecutionAfterException ?
new DelegatingErrorHandlingRunnable(task.getRunnable(), TaskUtils.LOG_AND_SUPPRESS_ERROR_HANDLER) :
new DelegatingErrorHandlingRunnable(task.getRunnable(), TaskUtils.LOG_AND_PROPAGATE_ERROR_HANDLER));
}
@Override
public ScheduledExecutorService getObject() {
return this.exposedExecutor;
}
@Override
public Class getObjectType() {
return (this.exposedExecutor != null ? this.exposedExecutor.getClass() : ScheduledExecutorService.class);
}
@Override
public boolean isSingleton() {
return true;
}
}