64 lines
2.5 KiB
Java
64 lines
2.5 KiB
Java
/**
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*
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* Copyright 2015 Florian Schmaus
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package org.jivesoftware.smack.util;
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import java.util.concurrent.ArrayBlockingQueue;
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import java.util.concurrent.RejectedExecutionException;
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import java.util.concurrent.Semaphore;
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import java.util.concurrent.ThreadFactory;
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import java.util.concurrent.ThreadPoolExecutor;
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import java.util.concurrent.TimeUnit;
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public class BoundedThreadPoolExecutor extends ThreadPoolExecutor {
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private final Semaphore semaphore;
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public BoundedThreadPoolExecutor(int corePoolSize, int maximumPoolSize, long keepAliveTime,
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TimeUnit unit, int bound, ThreadFactory threadFactory) {
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// One could think that the array blocking queue bound should be "bound - 1" because the bound protected by the
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// Semaphore also includes the "slot" in the worker thread executing the Runnable. But using that as bound could
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// actually cause a RejectedExecutionException as the queue could fill up while the worker thread remains
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// unscheduled and is thus not removing any entries.
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super(corePoolSize, maximumPoolSize, keepAliveTime,
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unit, new ArrayBlockingQueue<Runnable>(bound), threadFactory);
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semaphore = new Semaphore(bound);
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}
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public void executeBlocking(final Runnable command) throws InterruptedException {
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semaphore.acquire();
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try {
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execute(new Runnable() {
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@Override
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public void run() {
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try {
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command.run();
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} finally {
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semaphore.release();
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}
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}
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});
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} catch (Exception e) {
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semaphore.release();
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if (e instanceof RejectedExecutionException) {
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throw (RejectedExecutionException) e;
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} else {
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throw new RuntimeException(e);
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}
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}
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}
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}
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