java并发编程中的ReentrantLock（一）

package com.wangan.logistic;

import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;

public class WanganReentrantLockService {
    private Lock lock = new ReentrantLock();
    private Condition condition = lock.newCondition();
    
    private void await() {
        try {
            lock.lock();
            System.out.println(Thread.currentThread().getName() + "线程获得了lock");
            System.out.println(Thread.currentThread().getName() + "线程await,暂交出锁，并进入等待队列");
            condition.await();
            System.out.println(Thread.currentThread().getName() + "线程被从await唤醒，获得之前交出的锁并继续执行");
        } catch (InterruptedException e) {
            e.printStackTrace();
        }finally {
            lock.unlock();
            System.out.println(Thread.currentThread().getName() + "线程释放了lock");
        }
    }
    
    private void signal() {
        try {
            lock.lock();
            System.out.println(Thread.currentThread().getName() + "线程获得了lock");
            condition.signal();
            System.out.println(Thread.currentThread().getName() + "线程发出signal，非公平唤醒等待队列中的其他线程");
        } catch (Exception e) {
            e.printStackTrace();
        }finally {
            lock.unlock();
            System.out.println(Thread.currentThread().getName() + "线程释放了锁");
        }
    }
    
    
    public static void main(String[] args) {
        WanganReentrantLockService service = new WanganReentrantLockService();
        new Thread(new Runnable() {
            @Override
            public void run() {
                /*
                 * 这块可以模拟一下如果这个线程比main线程跑的慢，会发生什么
                    try {
                        Thread.sleep(5000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                */
                service.await();
            }
        }).start();
        try {
            Thread.sleep(3000);    //防止main线程跑得比Thread-0还快
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        service.signal();
    }
}

Thread-0线程获得了lock
Thread-0线程await,暂交出锁，并进入等待队列
main线程获得了lock
main线程发出signal，非公平唤醒等待队列中的其他线程
main线程释放了锁
Thread-0线程被从await唤醒，获得之前交出的锁并继续执行
Thread-0线程释放了lock

main线程获得了lock
main线程发出signal，非公平唤醒等待队列中的其他线程
main线程释放了锁
Thread-0线程获得了lock
Thread-0线程await,暂交出锁，并进入等待队列