package book.thread;

/**
 * Daemon(守護)線程 
 * Daemon線程區別一般線程之處是： 
 * 只有虛擬機中的用戶線程（非Daimon線程）全部結束，Daemon線程就會立即結束,并且也不會調用finally里的語句。
 * daemon線程所產生的所有線程都是daemon的
 */
public class Daemon {

	static class MainThread extends Thread {

		public void run() {
			System.out.println("MainThread is daemon? " + this.isDaemon());
			System.out.println("MainThread begin!");
			//啟動子線程
			Thread sub1 = new SubThread();
			//sub1線程為守護線程
			sub1.setDaemon(true);
			sub1.start();
			try {
				Thread.sleep(1000);
			}catch (InterruptedException e) {
				e.printStackTrace();
			} finally {
				System.out.println("MainThread" + " finally");
			}
			System.out.println("MainThread end!");
		}
	}

	static class SubThread extends Thread {

		public void run() {
			System.out.println("SubThread is daemon? " + this.isDaemon());
			System.out.println("SubThread begin!");
			int i = 0;
			try {
				while (i < 10) {
					System.out.println("SubThread  " + i++);
					Thread.sleep(200);
				}
			} catch (InterruptedException e) {
				e.printStackTrace();
			} finally {
				System.out.println("SubThread finally");
			}
			System.out.println("SubThread end!");
		}
	}

	public static void main(String[] args) {
		System.out.println("Main begin!");
		//默認情況下mainThread是普通線程
		Thread mainThread = new MainThread();
		//啟動mainThread線程
		mainThread.start();
		try {
			Thread.sleep(500);
		} catch (InterruptedException e1) {
			e1.printStackTrace();
		}
		System.out.println("Main end!");
	}
}