（一）線程管理_9---線程分組( Thread Group )

線程分組( Thread Group ) 

Java Concurrent API中提供了對線程進行分組管理的ThreadGroup，使得咱們能夠將多個線程看做一個單元，對這些線程執行操做，如中斷一組線程等；

下面實現一個例子，建立十個線程，每一個線程在運行期間隨機睡眠一段時間，當其中一個線程執行結束，主線成中斷其它全部線程；

動手實現

public class SearchTask implements Runnable {
    @Override
    public void run() {
        String name = Thread.currentThread().getName();
        System.out.printf("Thread_%s: Start\n", name);
        try {
            doTask();
        } catch (InterruptedException e) {
            System.out.printf("Thread %s: Interrupted\n", name);
        }
        System.out.printf("Thread %s: End\n", name);
    }

    private void doTask() throws InterruptedException {
        Random random = new Random((new Date()).getTime());
        int value = (int) (random.nextDouble() * 100);
        System.out.printf("Thread_%s: %d\n", Thread.currentThread().getName(), value);
        TimeUnit.SECONDS.sleep(value);
    }

    public static void main(String[] args) {
        ThreadGroup threadGroup = new ThreadGroup("Searcher");
        SearchTask searchTask=new SearchTask();
        for (int i = 0; i < 10; i++) {
            Thread thread = new Thread(threadGroup,searchTask);
            thread.start();
            try {
                TimeUnit.SECONDS.sleep(1);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }

        System.out.printf("Number of Threads:%d\n", threadGroup.activeCount());
        System.out.printf("Information of the Thread Group\n");
        threadGroup.list();
        Thread[] threads = new Thread[threadGroup.activeCount()];
        threadGroup.enumerate(threads);
        for (Thread thread : threads) {
            System.out.printf("Thread ====%s: %s\n", thread.getName(), thread.getState());
        }

        // Wait unit one of the threads fo ThreadGroup objects ends.
        waitFinish(threadGroup);

        threadGroup.interrupt();

    }

    private static void waitFinish(ThreadGroup threadGroup) {
        while (threadGroup.activeCount() > 9) {
            try {
                TimeUnit.SECONDS.sleep(1);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
    }
}

一次運行結果

Thread_Thread-0: Start
Thread_Thread-0: 1
Thread_Thread-1: Start
Thread_Thread-1: 82
Thread Thread-0: End
Thread_Thread-2: Start
Thread_Thread-2: 73
Thread_Thread-3: Start
Thread_Thread-3: 1
Thread_Thread-4: Start
Thread_Thread-4: 91
Thread Thread-3: End
Thread_Thread-5: Start
Thread_Thread-5: 17
Thread_Thread-6: Start
Thread_Thread-6: 8
Thread_Thread-7: Start
Thread_Thread-7: 36
Thread_Thread-8: Start
Thread_Thread-8: 27
Thread_Thread-9: Start
Thread_Thread-9: 7
Number of Threads:8
Information of the Thread Group
java.lang.ThreadGroup[name=Searcher,maxpri=10]
    Thread[Thread-1,5,Searcher]
    Thread[Thread-2,5,Searcher]
    Thread[Thread-4,5,Searcher]
    Thread[Thread-5,5,Searcher]
    Thread[Thread-6,5,Searcher]
    Thread[Thread-7,5,Searcher]
    Thread[Thread-8,5,Searcher]
    Thread[Thread-9,5,Searcher]
Thread ====Thread-1: TIMED_WAITING
Thread ====Thread-2: TIMED_WAITING
Thread ====Thread-4: TIMED_WAITING
Thread ====Thread-5: TIMED_WAITING
Thread ====Thread-6: TIMED_WAITING
Thread ====Thread-7: TIMED_WAITING
Thread ====Thread-8: TIMED_WAITING
Thread ====Thread-9: TIMED_WAITING
Thread Thread-4: Interrupted
Thread Thread-9: Interrupted
Thread Thread-9: End
Thread Thread-2: Interrupted
Thread Thread-2: End
Thread Thread-8: Interrupted
Thread Thread-8: End
Thread Thread-7: Interrupted
Thread Thread-6: Interrupted
Thread Thread-6: End
Thread Thread-5: Interrupted
Thread Thread-1: Interrupted
Thread Thread-1: End
Thread Thread-5: End
Thread Thread-7: End
Thread Thread-4: End

要點

ThreadGroup中還有許多其餘的方法，具體詳見JAVA API