package book.thread;

public class ListAllRunningThread {
	/**
	 * 列出所有線程的信息
	 */
	public static void list(){
		//獲取當(dāng)前線程所屬線程組的父線程組
	    ThreadGroup root = Thread.currentThread().getThreadGroup().getParent();
	    //不斷循環(huán)，直到找到根線程組
	    while (root.getParent() != null) {
	        root = root.getParent();
	    }
	    //訪問(wèn)根線程組下的線程
	    visit(root, 0);
	}
    /**
     * 遞歸的顯示線程組中的線程
     * @param group
     * @param level
     */
    private static void visit(ThreadGroup group, int level) {
        // 獲取group線程組中活動(dòng)線程的估計(jì)數(shù)
        int numThreads = group.activeCount();
        Thread[] threads = new Thread[numThreads];
        // 把此線程組中的所有活動(dòng)線程復(fù)制到指定數(shù)組中。
        // false表示不包括作為此線程組的子組的線程組中的線程。
        numThreads = group.enumerate(threads, false);
    
        // 遍歷活動(dòng)線程數(shù)組，打印它們的名字
        for (int i=0; i<numThreads; i++) {
            // Get thread
            Thread thread = threads[i];
            for (int j=0; j<level; j++){
                System.out.print("  ");
            }
            System.out.println("" + thread.getName());
        }
    
        // 獲取group線程組中活動(dòng)子線程組的估計(jì)數(shù)
        int numGroups = group.activeGroupCount();
        ThreadGroup[] groups = new ThreadGroup[numGroups];
        // 把對(duì)此線程組中的所有活動(dòng)子組的引用復(fù)制到指定數(shù)組中。
        numGroups = group.enumerate(groups, false);
    
        // 遞歸的訪問(wèn)子線程組中的線程
        for (int i=0; i<numGroups; i++) {
            visit(groups[i], level+1);
        }
    }
	/**
	 * @param args
	 */
	public static void main(String[] args) {
		//建立一個(gè)線程組
		ThreadGroup group1 = new ThreadGroup("ThreadGroup-1");
		//建立3個(gè)線程并啟動(dòng)
		Thread[] threads1 = new Thread[3];
		for (int i=1; i<4; i++){
			//新的線程屬于group1線程組，以ThreadA為運(yùn)行對(duì)象，名字為"group1-ThreadA-i"
			threads1[i-1] = new Thread(group1, new ThreadA(i*2000), "group1-ThreadA-" + i);
			threads1[i-1].start();
		}
		//建立另一個(gè)線程組，屬于group1線程組
		ThreadGroup group2 = new ThreadGroup(group1, "ThreadGroup-2");
		//建立3個(gè)線程并啟動(dòng)
		Thread[] threads2 = new Thread[3];
		for (int i=1; i<4; i++){
			//新的線程屬于group2線程組，以ThreadA為運(yùn)行對(duì)象，名字為"group2-ThreadA-i"
			threads2[i-1] = new Thread(group2, new ThreadA(i*1000), "group2-ThreadA-" + i);
			threads2[i-1].start();
		}
		//列出所有活動(dòng)的線程的名字
	    System.out.println("當(dāng)前虛擬機(jī)中所有正在運(yùn)行的線程：");
		ListAllRunningThread.list();
	}
	
	static class ThreadA extends Thread{
		private long sleepTime = 100;
		public ThreadA(long time){
			this.sleepTime = time;
		}
		public void run(){
			try {
				Thread.sleep(this.sleepTime);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
		}
	}
}