com.pdd.pop.ext.glassfish.grizzly.threadpool.QueueLimitedThreadPool Maven / Gradle / Ivy
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package com.pdd.pop.ext.glassfish.grizzly.threadpool;
import java.util.concurrent.RejectedExecutionException;
import java.util.concurrent.Semaphore;
/**
* Need to evaluate queue size limit perf implications on this fixedpool variant.
* The atomic counter can in theory approach synchronized (lack of) scalability
* in heavy load situations.
*
* @author gustav trede
* @author Tigran Mkrtchyan
*/
final class QueueLimitedThreadPool extends FixedThreadPool {
private final Semaphore queuePermits;
/**
* @param config the {@link ThreadPoolConfig} to configure this pool.
*/
QueueLimitedThreadPool(ThreadPoolConfig config) {
super(config);
if (config.getQueueLimit() < 0) {
throw new IllegalArgumentException("maxQueuedTasks < 0");
}
queuePermits = new Semaphore(config.getQueueLimit());
}
@Override
public final void execute(Runnable command) {
if (command == null) { // must nullcheck to ensure queuesize is valid
throw new IllegalArgumentException("Runnable task is null");
}
if (!running) {
throw new RejectedExecutionException("ThreadPool is not running");
}
if (!queuePermits.tryAcquire()) {
onTaskQueueOverflow();
}
if (!workQueue.offer(command)) {
queuePermits.release();
onTaskQueueOverflow();
}
onTaskQueued(command);
}
@Override
protected final void beforeExecute(final Worker worker, final Thread t,
final Runnable r) {
super.beforeExecute(worker, t, r);
queuePermits.release();
}
}