Java concurrency之Condition条件_动力节点Java学院整理

// 造成当前线程在接到信号或被中断之前一直处于等待状态。
void await()
// 造成当前线程在接到信号、被中断或到达指定等待时间之前一直处于等待状态。
boolean await(long time, TimeUnit unit)
// 造成当前线程在接到信号、被中断或到达指定等待时间之前一直处于等待状态。
long awaitNanos(long nanosTimeout)
// 造成当前线程在接到信号之前一直处于等待状态。
void awaitUninterruptibly()
// 造成当前线程在接到信号、被中断或到达指定最后期限之前一直处于等待状态。
boolean awaitUntil(Date deadline)
// 唤醒一个等待线程。
void signal()
// 唤醒所有等待线程。
void signalAll()

public class WaitTest1 {
  public static void main(String[] args) {
    ThreadA ta = new ThreadA("ta");
    synchronized(ta) { // 通过synchronized(ta)获取“对象ta的同步锁”
      try {
        System.out.println(Thread.currentThread().getName()+" start ta");
        ta.start();
        System.out.println(Thread.currentThread().getName()+" block");
        ta.wait();  // 等待
        System.out.println(Thread.currentThread().getName()+" continue");
      } catch (InterruptedException e) {
        e.printStackTrace();
      }
    }
  }
  static class ThreadA extends Thread{
    public ThreadA(String name) {
      super(name);
    }
    public void run() {
      synchronized (this) { // 通过synchronized(this)获取“当前对象的同步锁”
        System.out.println(Thread.currentThread().getName()+" wakup others");
        notify();  // 唤醒“当前对象上的等待线程”
      }
    }
  }
}

import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.ReentrantLock;
public class ConditionTest1 {
  private static Lock lock = new ReentrantLock();
  private static Condition condition = lock.newCondition();
  public static void main(String[] args) {
    ThreadA ta = new ThreadA("ta");
    lock.lock(); // 获取锁
    try {
      System.out.println(Thread.currentThread().getName()+" start ta");
      ta.start();
      System.out.println(Thread.currentThread().getName()+" block");
      condition.await();  // 等待
      System.out.println(Thread.currentThread().getName()+" continue");
    } catch (InterruptedException e) {
      e.printStackTrace();
    } finally {
      lock.unlock();  // 释放锁
    }
  }
  static class ThreadA extends Thread{
    public ThreadA(String name) {
      super(name);
    }
    public void run() {
      lock.lock();  // 获取锁
      try {
        System.out.println(Thread.currentThread().getName()+" wakup others");
        condition.signal();  // 唤醒“condition所在锁上的其它线程”
      } finally {
        lock.unlock();  // 释放锁
      }
    }
  }
}

main start ta
main block
ta wakup others
main continue

import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.ReentrantLock;
class BoundedBuffer {
  final Lock lock = new ReentrantLock();
  final Condition notFull = lock.newCondition(); 
  final Condition notEmpty = lock.newCondition(); 
  final Object[] items = new Object[5];
  int putptr, takeptr, count;
  public void put(Object x) throws InterruptedException {
    lock.lock();  //获取锁
    try {
      // 如果“缓冲已满”，则等待；直到“缓冲”不是满的，才将x添加到缓冲中。
      while (count == items.length)
        notFull.await();
      // 将x添加到缓冲中
      items[putptr] = x; 
      // 将“put统计数putptr+1”；如果“缓冲已满”，则设putptr为0。
      if (++putptr == items.length) putptr = 0;
      // 将“缓冲”数量+1
      ++count;
      // 唤醒take线程，因为take线程通过notEmpty.await()等待
      notEmpty.signal();
      // 打印写入的数据
      System.out.println(Thread.currentThread().getName() + " put "+ (Integer)x);
    } finally {
      lock.unlock();  // 释放锁
    }
  }
  public Object take() throws InterruptedException {
    lock.lock();  //获取锁
    try {
      // 如果“缓冲为空”，则等待；直到“缓冲”不为空，才将x从缓冲中取出。
      while (count == 0) 
        notEmpty.await();
      // 将x从缓冲中取出
      Object x = items[takeptr]; 
      // 将“take统计数takeptr+1”；如果“缓冲为空”，则设takeptr为0。
      if (++takeptr == items.length) takeptr = 0;
      // 将“缓冲”数量-1
      --count;
      // 唤醒put线程，因为put线程通过notFull.await()等待
      notFull.signal();
      // 打印取出的数据
      System.out.println(Thread.currentThread().getName() + " take "+ (Integer)x);
      return x;
    } finally {
      lock.unlock();  // 释放锁
    }
  } 
}
public class ConditionTest2 {
  private static BoundedBuffer bb = new BoundedBuffer();
  public static void main(String[] args) {
    // 启动10个“写线程”，向BoundedBuffer中不断的写数据(写入0-9)；
    // 启动10个“读线程”，从BoundedBuffer中不断的读数据。
    for (int i=0; i<10; i++) {
      new PutThread("p"+i, i).start();
      new TakeThread("t"+i).start();
    }
  }
  static class PutThread extends Thread {
    private int num;
    public PutThread(String name, int num) {
      super(name);
      this.num = num;
    }
    public void run() {
      try {
        Thread.sleep(1);  // 线程休眠1ms
        bb.put(num);    // 向BoundedBuffer中写入数据
      } catch (InterruptedException e) {
      }
    }
  }
  static class TakeThread extends Thread {
    public TakeThread(String name) {
      super(name);
    }
    public void run() {
      try {
        Thread.sleep(10);          // 线程休眠1ms
        Integer num = (Integer)bb.take();  // 从BoundedBuffer中取出数据
      } catch (InterruptedException e) {
      }
    }
  }
}