java.lang.ThreadGroup.activeGroupCount()%uA0方法返回活动线程组的数目估计值。
声明
以下是java.lang.ThreadGroup.activeGroupCount()方法的声明
public int activeGroupCount()
参数
-
NA
返回值
此方法返回活动线程组的数量与该线程组作为祖先。
异常
-
NA
例子
下面的例子显示java.lang.ThreadGroup.activeGroupCount()方法的使用。
package com.yiibai import java.lang.* public class ThreadGroupDemo implements Runnable { public static void main(String[] args) { ThreadGroupDemo tg = new ThreadGroupDemo() tg.func() } public void func() { try { // create a parent ThreadGroup ThreadGroup pGroup = new ThreadGroup("Parent ThreadGroup") // create a child ThreadGroup for parent ThreadGroup ThreadGroup cGroup = new ThreadGroup(pGroup, "Child ThreadGroup") // create a thread Thread t1 = new Thread(pGroup, this) System.out.println("Starting " + t1.getName() + "...") t1.start() // create another thread Thread t2 = new Thread(cGroup, this) System.out.println("Starting " + t2.getName() + "...") t2.start() /* returns the number of active thread groups with this thread group as an ancestor */ System.out.println("Active group(child) threads in "" + pGroup.getName() + "" = " + pGroup.activeCount()) // block until the other threads finish t1.join() t2.join() } catch (InterruptedException ex) { System.out.println(ex.toString()) } } // implements run() public void run() { for(int i=0i<1000i++) { i++ } System.out.println(Thread.currentThread().getName() + " finished executing.") } }
让我们来编译和运行上面的程序，这将产生以下结果：
Starting Thread-0... Starting Thread-1... Active group(child) threads in "Parent ThreadGroup" = 1 Thread-0 finished executing Thread-1 finished executing