001 /**
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017 package org.apache.camel.util.concurrent;
018
019 import java.util.Collection;
020 import java.util.List;
021 import java.util.concurrent.Callable;
022 import java.util.concurrent.ExecutionException;
023 import java.util.concurrent.Future;
024 import java.util.concurrent.RejectedExecutionException;
025 import java.util.concurrent.RejectedExecutionHandler;
026 import java.util.concurrent.ScheduledExecutorService;
027 import java.util.concurrent.ScheduledFuture;
028 import java.util.concurrent.ScheduledThreadPoolExecutor;
029 import java.util.concurrent.ThreadFactory;
030 import java.util.concurrent.TimeUnit;
031 import java.util.concurrent.TimeoutException;
032
033 import org.slf4j.Logger;
034 import org.slf4j.LoggerFactory;
035
036 /**
037 * A sized {@link ScheduledExecutorService} which will reject executing tasks if the task queue is full.
038 * <p/>
039 * The {@link ScheduledThreadPoolExecutor} which is the default implementation of the {@link ScheduledExecutorService}
040 * has unbounded task queue, which mean you can keep scheduling tasks which may cause the system to run out of memory.
041 * <p/>
042 * This class is a wrapped for {@link ScheduledThreadPoolExecutor} to reject executing tasks if an upper limit
043 * of the task queue has been reached.
044 */
045 public class SizedScheduledExecutorService implements ScheduledExecutorService {
046
047 private static final Logger LOG = LoggerFactory.getLogger(SizedScheduledExecutorService.class);
048 private final ScheduledThreadPoolExecutor delegate;
049 private final long queueSize;
050
051 /**
052 * Creates a new sized {@link ScheduledExecutorService} with the given queue size as upper task limit.
053 *
054 * @param delegate the delegate of the actual thread pool implementation
055 * @param queueSize the upper queue size, use 0 or negative value for unlimited
056 */
057 public SizedScheduledExecutorService(ScheduledThreadPoolExecutor delegate, long queueSize) {
058 this.delegate = delegate;
059 this.queueSize = queueSize;
060 }
061
062 /**
063 * Gets the wrapped {@link ScheduledThreadPoolExecutor}
064 */
065 public ScheduledThreadPoolExecutor getScheduledThreadPoolExecutor() {
066 return delegate;
067 }
068
069 @Override
070 public <V> ScheduledFuture<V> schedule(Callable<V> task, long delay, TimeUnit timeUnit) {
071 if (canScheduleOrExecute()) {
072 return delegate.schedule(task, delay, timeUnit);
073 } else {
074 throw new RejectedExecutionException("Task rejected due queue size limit reached");
075 }
076 }
077
078 @Override
079 public ScheduledFuture<?> schedule(Runnable task, long delay, TimeUnit timeUnit) {
080 if (canScheduleOrExecute()) {
081 return delegate.schedule(task, delay, timeUnit);
082 } else {
083 throw new RejectedExecutionException("Task rejected due queue size limit reached");
084 }
085 }
086
087 @Override
088 public ScheduledFuture<?> scheduleAtFixedRate(Runnable task, long initialDelay, long period, TimeUnit timeUnit) {
089 if (canScheduleOrExecute()) {
090 return delegate.scheduleAtFixedRate(task, initialDelay, period, timeUnit);
091 } else {
092 throw new RejectedExecutionException("Task rejected due queue size limit reached");
093 }
094 }
095
096 @Override
097 public ScheduledFuture<?> scheduleWithFixedDelay(Runnable task, long initialDelay, long period, TimeUnit timeUnit) {
098 if (canScheduleOrExecute()) {
099 return delegate.scheduleWithFixedDelay(task, initialDelay, period, timeUnit);
100 } else {
101 throw new RejectedExecutionException("Task rejected due queue size limit reached");
102 }
103 }
104
105 @Override
106 public boolean awaitTermination(long timeout, TimeUnit timeUnit) throws InterruptedException {
107 return delegate.awaitTermination(timeout, timeUnit);
108 }
109
110 public int getActiveCount() {
111 return delegate.getActiveCount();
112 }
113
114 public long getCompletedTaskCount() {
115 return delegate.getCompletedTaskCount();
116 }
117
118 public int getCorePoolSize() {
119 return delegate.getCorePoolSize();
120 }
121
122 public long getKeepAliveTime(TimeUnit timeUnit) {
123 return delegate.getKeepAliveTime(timeUnit);
124 }
125
126 public int getLargestPoolSize() {
127 return delegate.getLargestPoolSize();
128 }
129
130 public int getMaximumPoolSize() {
131 return delegate.getMaximumPoolSize();
132 }
133
134 public int getPoolSize() {
135 return delegate.getPoolSize();
136 }
137
138 public RejectedExecutionHandler getRejectedExecutionHandler() {
139 return delegate.getRejectedExecutionHandler();
140 }
141
142 public long getTaskCount() {
143 return delegate.getTaskCount();
144 }
145
146 public ThreadFactory getThreadFactory() {
147 return delegate.getThreadFactory();
148 }
149
150 @Override
151 public <T> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks) throws InterruptedException {
152 if (canScheduleOrExecute()) {
153 return delegate.invokeAll(tasks);
154 } else {
155 throw new RejectedExecutionException("Task rejected due queue size limit reached");
156 }
157 }
158
159 @Override
160 public <T> List<Future<T>> invokeAll(Collection<? extends Callable<T>> tasks, long timeout, TimeUnit timeUnit) throws InterruptedException {
161 if (canScheduleOrExecute()) {
162 return delegate.invokeAll(tasks, timeout, timeUnit);
163 } else {
164 throw new RejectedExecutionException("Task rejected due queue size limit reached");
165 }
166 }
167
168 @Override
169 public <T> T invokeAny(Collection<? extends Callable<T>> tasks) throws InterruptedException, ExecutionException {
170 if (canScheduleOrExecute()) {
171 return delegate.invokeAny(tasks);
172 } else {
173 throw new RejectedExecutionException("Task rejected due queue size limit reached");
174 }
175 }
176
177 @Override
178 public <T> T invokeAny(Collection<? extends Callable<T>> tasks, long timeout, TimeUnit timeUnit) throws InterruptedException, ExecutionException, TimeoutException {
179 if (canScheduleOrExecute()) {
180 return delegate.invokeAny(tasks, timeout, timeUnit);
181 } else {
182 throw new RejectedExecutionException("Task rejected due queue size limit reached");
183 }
184 }
185
186 @Override
187 public boolean isShutdown() {
188 return delegate.isShutdown();
189 }
190
191 @Override
192 public boolean isTerminated() {
193 return delegate.isTerminated();
194 }
195
196 public boolean isTerminating() {
197 return delegate.isTerminating();
198 }
199
200 public int prestartAllCoreThreads() {
201 return delegate.prestartAllCoreThreads();
202 }
203
204 public boolean prestartCoreThread() {
205 return delegate.prestartCoreThread();
206 }
207
208 public void purge() {
209 delegate.purge();
210 }
211
212 public void setCorePoolSize(int corePoolSize) {
213 delegate.setCorePoolSize(corePoolSize);
214 }
215
216 public void setKeepAliveTime(long keepAliveTime, TimeUnit timeUnit) {
217 delegate.setKeepAliveTime(keepAliveTime, timeUnit);
218 }
219
220 public void setMaximumPoolSize(int maximumPoolSize) {
221 delegate.setMaximumPoolSize(maximumPoolSize);
222 }
223
224 public void setRejectedExecutionHandler(RejectedExecutionHandler rejectedExecutionHandler) {
225 delegate.setRejectedExecutionHandler(rejectedExecutionHandler);
226 }
227
228 public void setThreadFactory(ThreadFactory threadFactory) {
229 delegate.setThreadFactory(threadFactory);
230 }
231
232 @Override
233 public void shutdown() {
234 delegate.shutdown();
235 }
236
237 @Override
238 public List<Runnable> shutdownNow() {
239 return delegate.shutdownNow();
240 }
241
242 @Override
243 public <T> Future<T> submit(Callable<T> task) {
244 if (canScheduleOrExecute()) {
245 return delegate.submit(task);
246 } else {
247 throw new RejectedExecutionException("Task rejected due queue size limit reached");
248 }
249 }
250
251 @Override
252 public Future<?> submit(Runnable task) {
253 if (canScheduleOrExecute()) {
254 return delegate.submit(task);
255 } else {
256 throw new RejectedExecutionException("Task rejected due queue size limit reached");
257 }
258 }
259
260 @Override
261 public <T> Future<T> submit(Runnable task, T result) {
262 if (canScheduleOrExecute()) {
263 return delegate.submit(task, result);
264 } else {
265 throw new RejectedExecutionException("Task rejected due queue size limit reached");
266 }
267 }
268
269 @Override
270 public void execute(Runnable task) {
271 if (canScheduleOrExecute()) {
272 delegate.execute(task);
273 } else {
274 throw new RejectedExecutionException("Task rejected due queue size limit reached");
275 }
276 }
277
278 public void allowCoreThreadTimeOut(boolean value) {
279 delegate.allowCoreThreadTimeOut(value);
280 }
281
282 public boolean allowsCoreThreadTimeOut() {
283 return delegate.allowsCoreThreadTimeOut();
284 }
285
286 /**
287 * Can the task be scheduled or executed?
288 *
289 * @return <tt>true</tt> to accept, <tt>false</tt> to not accept
290 */
291 protected boolean canScheduleOrExecute() {
292 if (queueSize <= 0) {
293 return true;
294 }
295
296 int size = delegate.getQueue().size();
297 boolean answer = size < queueSize;
298 if (LOG.isTraceEnabled()) {
299 LOG.trace("canScheduleOrExecute {} < {} -> {}", new Object[]{size, queueSize, answer});
300 }
301 return answer;
302 }
303
304 @Override
305 public String toString() {
306 // the thread factory often have more precise details what the thread pool is used for
307 if (delegate.getThreadFactory() instanceof CamelThreadFactory) {
308 String name = ((CamelThreadFactory) delegate.getThreadFactory()).getName();
309 return super.toString() + "[" + name + "]";
310 } else {
311 return super.toString();
312 }
313 }
314 }