Java ThreadGroup enumerate()方法

ThreadGroup類的enumerate()方法用於將每個活動執行緒的執行緒組及其子組複製到指定的陣列中。 此方法使用tarray引數呼叫`enumerate()方法。

語法

public int enumerate(Thread[] tarray)

引數

• tarray:它是要複製到的Thread物件陣列。

返回

此方法返回放入陣列的執行緒數。

package com.yiibai.threadgroup;

class NewThread extends Thread {
    NewThread(String threadname, ThreadGroup tg) {
        super(tg, threadname);
    }

    public void run() {
        for (int i = 0; i < 10; i++) {
            try {
                Thread.sleep(10);
            } catch (InterruptedException ex) {
                System.out.println(Thread.currentThread().getName() + " interrupted");
            }
        }
        System.out.println(Thread.currentThread().getName() + " completed executing");
    }
}

public class ThreadGroupEnumerateExp {
    public static void main(String arg[]) {
        // creating the ThreadGroup
        ThreadGroup g1 = new ThreadGroup("Parent thread");
        // creating a child ThreadGroup for parent ThreadGroup
        ThreadGroup g2 = new ThreadGroup(g1, "child thread");

        // creating a thread
        NewThread t1 = new NewThread("Thread-1", g1);
        System.out.println("Starting of Thread-1");
        t1.start();
        // creating another thread
        NewThread t2 = new NewThread("Thread-2", g1);
        System.out.println("Starting of Thread-2");
        t2.start();

        // returns the number of threads put into the array
        Thread[] tarray = new Thread[g1.activeCount()];
        int count = g1.enumerate(tarray);

        // prints active threads
        for (int i = 0; i < count; i++)
            System.out.println(tarray[i].getName() + " found");
    }
}

執行上面範例程式碼，得到以下結果:

Starting of Thread-1
Starting of Thread-2
Thread-1 found
Thread-2 found
Thread-1 completed executing
Thread-2 completed executing