如何实现阻塞线程池执行器?:How to implement blocking thread pool executor?

我们有一个很大的文本文件，其中每一行都需要大量的 process .该设计将具有一个 class ，该类读取文件并通过 thread pool 将每一行的处理委托给 thread .一旦池中没有空闲线程可以进行处理，则应阻止文件读取器类读取下一行.所以我需要一个阻塞线程池

We have a large text file in which each line requires intensive process. The design is to have a class that reads the file and delegates the processing of each line to a thread, via thread pool. The file reader class should be blocked from reading the next line once there is no free thread in the pool to do the processing. So i need a blocking thread pool

在当前实现中， ThreadPoolExecutor.submit()和 ThreadPoolExecutor.execute()方法在配置的线程数获取后抛出 RejectedExecutionException 异常如下面的代码片段所示，我很忙.

In the current implementation ThreadPoolExecutor.submit() and ThreadPoolExecutor.execute() methods throw RejectedExecutionException exception after the configured # of threads get busy as i showed in code snippet below.

public class BlockingTp { public static void main(String[] args) { ArrayBlockingQueue arrayBlockingQueue = new ArrayBlockingQueue(3); ThreadPoolExecutor executorService= new ThreadPoolExecutor(1, 3, 30, TimeUnit.SECONDS, arrayBlockingQueue); int Jobs = 10; System.out.println("Starting application with " + Jobs + " jobs"); for (int i = 1; i <= Jobs; i++) try { executorService.submit(new WorkerThread(i)); System.out.println("job added " + (i)); } catch (RejectedExecutionException e) { System.err.println("RejectedExecutionException"); } } } class WorkerThread implements Runnable { int job; public WorkerThread(int job) { this.job = job; } public void run() { try { Thread.sleep(1000); } catch (Exception excep) { } } } 

以上程序的输出为

Starting application to add 10 jobs Added job #1 Added job #2 Added job #3 Added job #4 Added job #5 Added job #6 RejectedExecutionException RejectedExecutionException RejectedExecutionException RejectedExecutionException 

有人可以说点什么，就是说我如何实现阻塞线程池.

Can some one throw some light i.e how i can implement blocking thread pool.

问题解答

有人可以提供一些启示，即我如何实现阻塞线程池.

Can some one throw some light i.e how i can implement blocking thread pool.

您需要在执行程序服务上设置拒绝执行处理程序.

You need to set a rejection execution handler on your executor service.

BlockingQueue arrayBlockingQueue = new ArrayBlockingQueue(3); ThreadPoolExecutor executorService = new ThreadPoolExecutor(1, 3, 30, TimeUnit.SECONDS, arrayBlockingQueue); // when the blocking queue is full, this tries to put into the queue which blocks executorService.setRejectedExecutionHandler(new RejectedExecutionHandler() { @Override public void rejectedExecution(Runnable r, ThreadPoolExecutor executor) { try { // block until there's room executor.getQueue().put(r); } catch (InterruptedException e) { Thread.currentThread().interrupt(); throw new RejectedExecutionException("Producer thread interrupted", e); } } }); 

因此，它不会调用TRE抛出 RejectedExecutionException ，而是将调用拒绝处理程序，该处理程序将依次尝试将作业放回队列.这会阻止呼叫者.

So instead of the TRE throwing a RejectedExecutionException, it will call the rejection handler which will in turn try to put the job back on the queue. This blocks the caller.

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