/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF 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.apache.camel.util.concurrent;
import java.util.Collection;
import java.util.List;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
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 java.util.concurrent.TimeoutException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* A sized {@link ScheduledExecutorService} which will reject executing tasks if the task queue is full.
* <p/>
* The {@link ScheduledThreadPoolExecutor} which is the default implementation of the {@link ScheduledExecutorService}
* has unbounded task queue, which mean you can keep scheduling tasks which may cause the system to run out of memory.
* <p/>
* This class is a wrapped for {@link ScheduledThreadPoolExecutor} to reject executing tasks if an upper limit
* of the task queue has been reached.
*/
public class SizedScheduledExecutorService implements ScheduledExecutorService {
private static final Logger LOG = LoggerFactory.getLogger(SizedScheduledExecutorService.class);
private final ScheduledThreadPoolExecutor delegate;
private final long queueSize;
/**
* Creates a new sized {@link ScheduledExecutorService} with the given queue size as upper task limit.
*
* @param delegate the delegate of the actual thread pool implementation
* @param queueSize the upper queue size, use 0 or negative value for unlimited
*/
public SizedScheduledExecutorService(ScheduledThreadPoolExecutor delegate, long queueSize) {
this.delegate = delegate;
this.queueSize = queueSize;
}
/**
* Gets the wrapped {@link ScheduledThreadPoolExecutor}
*/
public ScheduledThreadPoolExecutor getScheduledThreadPoolExecutor() {
return delegate;
}
@Override
public <V> ScheduledFuture<V> schedule(Callable<V> task, long delay, TimeUnit timeUnit) {
if (canScheduleOrExecute()) {
return delegate.schedule(task, delay, timeUnit);
} else {
throw new RejectedExecutionException("Task rejected due queue size limit reached");
}
}
@Override
public ScheduledFuture<?> schedule(Runnable task, long delay, TimeUnit timeUnit) {
if (canScheduleOrExecute()) {
return delegate.schedule(task, delay, timeUnit);
} else {
throw new RejectedExecutionException("Task rejected due queue size limit reached");
}
}
@Override
public ScheduledFuture<?> scheduleAtFixedRate(Runnable task, long initialDelay, long period, TimeUnit timeUnit) {
if (canScheduleOrExecute()) {
return delegate.scheduleAtFixedRate(task, initialDelay, period, timeUnit);
} else {
throw new RejectedExecutionException("Task rejected due queue size limit reached");
}
}
@Override
public ScheduledFuture<?> scheduleWithFixedDelay(Runnable task, long initialDelay, long period, TimeUnit timeUnit) {
if (canScheduleOrExecute()) {
return delegate.scheduleWithFixedDelay(task, initialDelay, period, timeUnit);
} else {
throw new RejectedExecutionException("Task rejected due queue size limit reached");
}
}
@Override
public boolean awaitTermination(long timeout, TimeUnit timeUnit) throws InterruptedException {
return delegate.awaitTermination(timeout, timeUnit);
}
public int getActiveCount() {
return delegate.getActiveCount();
}
public long getCompletedTaskCount() {
return delegate.getCompletedTaskCount();
}
public int getCorePoolSize() {
return delegate.getCorePoolSize();
}
public long getKeepAliveTime(TimeUnit timeUnit) {
return delegate.getKeepAliveTime(timeUnit);
}
public int getLargestPoolSize() {
return delegate.getLargestPoolSize();
}
public int getMaximumPoolSize() {
return delegate.getMaximumPoolSize();
}
public int getPoolSize() {
return delegate.getPoolSize();
}
public RejectedExecutionHandler getRejectedExecutionHandler() {
return delegate.getRejectedExecutionHandler();
}
public long getTaskCount() {
return delegate.getTaskCount();
}
public ThreadFactory getThreadFactory() {
return delegate.getThreadFactory();
}
@Override
public <T> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks) throws InterruptedException {
if (canScheduleOrExecute()) {
return delegate.invokeAll(tasks);
} else {
throw new RejectedExecutionException("Task rejected due queue size limit reached");
}
}
@Override
public <T> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks, long timeout, TimeUnit timeUnit) throws InterruptedException {
if (canScheduleOrExecute()) {
return delegate.invokeAll(tasks, timeout, timeUnit);
} else {
throw new RejectedExecutionException("Task rejected due queue size limit reached");
}
}
@Override
public <T> T invokeAny(Collection<? extends Callable<T>> tasks) throws InterruptedException, ExecutionException {
if (canScheduleOrExecute()) {
return delegate.invokeAny(tasks);
} else {
throw new RejectedExecutionException("Task rejected due queue size limit reached");
}
}
@Override
public <T> T invokeAny(Collection<? extends Callable<T>> tasks, long timeout, TimeUnit timeUnit) throws InterruptedException, ExecutionException, TimeoutException {
if (canScheduleOrExecute()) {
return delegate.invokeAny(tasks, timeout, timeUnit);
} else {
throw new RejectedExecutionException("Task rejected due queue size limit reached");
}
}
@Override
public boolean isShutdown() {
return delegate.isShutdown();
}
@Override
public boolean isTerminated() {
return delegate.isTerminated();
}
public boolean isTerminating() {
return delegate.isTerminating();
}
public int prestartAllCoreThreads() {
return delegate.prestartAllCoreThreads();
}
public boolean prestartCoreThread() {
return delegate.prestartCoreThread();
}
public void purge() {
delegate.purge();
}
public void setCorePoolSize(int corePoolSize) {
delegate.setCorePoolSize(corePoolSize);
}
public void setKeepAliveTime(long keepAliveTime, TimeUnit timeUnit) {
delegate.setKeepAliveTime(keepAliveTime, timeUnit);
}
public void setMaximumPoolSize(int maximumPoolSize) {
delegate.setMaximumPoolSize(maximumPoolSize);
}
public void setRejectedExecutionHandler(RejectedExecutionHandler rejectedExecutionHandler) {
delegate.setRejectedExecutionHandler(rejectedExecutionHandler);
}
public void setThreadFactory(ThreadFactory threadFactory) {
delegate.setThreadFactory(threadFactory);
}
@Override
public void shutdown() {
delegate.shutdown();
}
@Override
public List<Runnable> shutdownNow() {
return delegate.shutdownNow();
}
@Override
public <T> Future<T> submit(Callable<T> task) {
if (canScheduleOrExecute()) {
return delegate.submit(task);
} else {
throw new RejectedExecutionException("Task rejected due queue size limit reached");
}
}
@Override
public Future<?> submit(Runnable task) {
if (canScheduleOrExecute()) {
return delegate.submit(task);
} else {
throw new RejectedExecutionException("Task rejected due queue size limit reached");
}
}
@Override
public <T> Future<T> submit(Runnable task, T result) {
if (canScheduleOrExecute()) {
return delegate.submit(task, result);
} else {
throw new RejectedExecutionException("Task rejected due queue size limit reached");
}
}
@Override
public void execute(Runnable task) {
if (canScheduleOrExecute()) {
delegate.execute(task);
} else {
throw new RejectedExecutionException("Task rejected due queue size limit reached");
}
}
public void allowCoreThreadTimeOut(boolean value) {
delegate.allowCoreThreadTimeOut(value);
}
public boolean allowsCoreThreadTimeOut() {
return delegate.allowsCoreThreadTimeOut();
}
/**
* Can the task be scheduled or executed?
*
* @return <tt>true</tt> to accept, <tt>false</tt> to not accept
*/
protected boolean canScheduleOrExecute() {
if (queueSize <= 0) {
return true;
}
int size = delegate.getQueue().size();
boolean answer = size < queueSize;
if (LOG.isTraceEnabled()) {
LOG.trace("canScheduleOrExecute {} < {} -> {}", new Object[]{size, queueSize, answer});
}
return answer;
}
@Override
public String toString() {
// the thread factory often have more precise details what the thread pool is used for
if (delegate.getThreadFactory() instanceof CamelThreadFactory) {
String name = ((CamelThreadFactory) delegate.getThreadFactory()).getName();
return super.toString() + "[" + name + "]";
} else {
return super.toString();
}
}
}