如何检查线程是否在线程ExecutorService池中运行?
背景:
我想在线程池中的线程之间进行同步,如果设置了标志。
因此,如果标志设置为true以进行同步,则必须检查其他线程是否正在运行,或者等待其完成,然后使用同步调用阻塞线程,以便其他线程将等待该阻塞线程完成。
如果未设置标志,则无需同步,并且可以并行执行线程。
谢谢!
如何检查线程是否在线程ExecutorService池中运行?
背景:
我想在线程池中的线程之间进行同步,如果设置了标志。
因此,如果标志设置为true以进行同步,则必须检查其他线程是否正在运行,或者等待其完成,然后使用同步调用阻塞线程,以便其他线程将等待该阻塞线程完成。
如果未设置标志,则无需同步,并且可以并行执行线程。
谢谢!
你需要使用一个Semaphore
。
这允许你拥有一定数量的"许可证"来完成工作。如果你只想同时运行一个任务,那么就使用一个带有一个许可证的Semaphore
,否则就使用一个许可证数大于线程池中Thread
数量的Semaphore
。
static class Worker implements Runnable {
final Semaphore semaphore;
public Worker(Semaphore semaphore) {
this.semaphore = semaphore;
}
@Override
public void run() {
try {
semaphore.acquire();
try {
//do stuff
} finally {
semaphore.release();
}
} catch (InterruptedException ex) {
Thread.currentThread().interrupt();
}
}
}
public static void main(String[] args) {
final int numThreads = 10;
final ExecutorService executorService = Executors.newFixedThreadPool(10);
final Semaphore semaphore;
boolean myflag = true;
if (myflag) {
semaphore = new Semaphore(1);
} else {
semaphore = new Semaphore(numThreads);
}
final Worker worker = new Worker(semaphore);
executorService.submit(worker);
}
newSingleThreadExecutor()
- 但我假设你知道这一点,由于某种原因不能使用它。static interface TaskBlocker {
void acquire();
void release();
}
static class Worker implements Runnable {
final TaskBlocker taskBlocker;
public Worker(TaskBlocker taskBlocker) {
this.taskBlocker = taskBlocker;
}
@Override
public void run() {
taskBlocker.acquire();
try {
//do stuff
} finally {
taskBlocker.release();
}
}
}
public static void main(String[] args) {
final int numThreads = 10;
final ExecutorService executorService = Executors.newFixedThreadPool(numThreads);
final TaskBlocker taskBlocker;
boolean myflag = true;
if (myflag) {
taskBlocker = new TaskBlocker() {
final Lock lock = new ReentrantLock();
@Override
public void acquire() {
lock.lock();
}
@Override
public void release() {
lock.unlock();
}
};
} else {
taskBlocker = new TaskBlocker() {
@Override
public void acquire() {
}
@Override
public void release() {
}
};
}
final Worker worker = new Worker(taskBlocker);
executorService.submit(worker);
}
Thread
,它怎么会做其他事情呢? - Boris the Spiderprivate static final String EXECUTOR_THREADNAME_PREFIX = "ExecutorThread";
ThreadFactory threadFactory = new ThreadFactory() {
private final AtomicInteger id = new AtomicInteger(0);
@Override
public Thread newThread(Runnable r) {
Thread thread = new Thread(r);
thread.setName(EXECUTOR_THREADNAME_PREFIX + "_" + id.incrementAndGet());
return thread;
}
};
myExecutor = Executors.newCachedThreadPool(threadFactory);
然后,在线程中,您只需检查名称是否以您的前缀开头:
if (Thread.currentThread().getName().startsWith(EXECUTOR_THREADNAME_PREFIX)) {
// In executor.
} else {
// Not in executor.
}