package test;

import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
//学习 tryLock
//tryLock()方法是有返回值的，它表示用来尝试获取锁，如果获取成功，则返回true，如果获取失败（即锁已被其他线程获取），则返回false，这个方法无论如何都会立即返回。在拿不到锁时不会一直在那等待。
public class tryLock {

	public static void main(String[] args) {
		
		System.out.println("开始");
		final Lock lock = new ReentrantLock();
		new Thread() {
			@Override
			public void run() {
				String tName = Thread.currentThread().getName();
				if (lock.tryLock()) {
					System.out.println(tName + "获取到锁！");
				} else {
					System.out.println(tName + "获取不到锁！");
					return;
				}
				try {
					for (int i = 0; i < 5; i++) {
						System.out.println(tName + ":" + i);
					}
					Thread.sleep(5000);
				} catch (Exception e) {
					System.out.println(tName + "出错了！！！");
				} finally {
					System.out.println(tName + "释放锁！！");
					lock.unlock();
				}

			}
		}.start();

		new Thread() {
			@Override
			public void run() {
				String tName = Thread.currentThread().getName();

				if (lock.tryLock()) {
					System.out.println(tName + "获取到锁！");
				} else {
					System.out.println(tName + "获取不到锁！");
					return;
				}

				try {
					for (int i = 0; i < 5; i++) {
						System.out.println(tName + ":" + i);
					}

				} catch (Exception e) {
					System.out.println(tName + "出错了！！！");
				} finally {
					System.out.println(tName + "释放锁！！");
					lock.unlock();
				}
			}
		}.start();
		
		System.out.println("结束");
	}
}