Java运行线程cykllu，等待线程完成

Question

I need to run in a cycle of four parallel threads that will be something to process and thread of late, so the cycle began Dasle 4 parallel threads. I have tried to implement, but the cycle starts over 4 threads. I miss checking if there threads they are completed or not. Can you advise me please? Thank you.

Answer 1

1. Create List with your jobs.
2. Wrap your jobs in some class that implements Runnable interface.
3. Create Thread that will execute your jobs from queue

Something like:

// This will run your jobs in threads
ExecutorService threadPoolExecutor = Executors.newFixedThreadPool(NUMBER_OF_THREADS);

// Adding new jobs to list
List<Job> processingList= Collections.synchronizedList(new ArrayList<Job>());
processingList.add(someJob1);
processingList.add(someJob2);
processingList.add(someJob3);
processingList.add(someJob4);

...

Runnable processor = new Runnable() {
    public void run() {
        // Run all jobs from List in threads
        for (Job job : processingList) {
            threadPoolExecutor.execute(job);
        }

        // wait till jobs are completed
        boolean areJobsCompleted = false;
        while(!areJobsCompleted) {
            boolean areJobsCompleted = true;

            for (Job job : processingList) {
                areJobsCompleted = areJobsCompleted && job.isComplete();
            }
        }
    }
};

Executors.newSingleThreadExecutor().execute(processor);