Lock和ReentrantLock

Posted on 2017-07-20 Edited on 2019-05-16

Lock

特征：

提供无条件的、可轮询的、定时的、可中断的锁获取操作
显式的加锁、解锁

实现类：

ReentrantLock
ReentrantReadWriteLock.ReadLock
ReentrantReadWriteLock.WriteLock

API：

public abstract interface Lock{
  //获取锁
  //如获取失败,禁用当前线程,知道得到锁之前,线程将一直处于休眠
  public abstract void lock();
  
  //获取锁
  //如获取失败，【同上】
  //线程在获取锁时被中断,抛出异常,清除当前线程的已中断状态
  //question: 锁中断如何使用
  public abstract void lockInterruptibly() throws InterruptedException;
  
  //仅在调用时，锁为空闲状态才获取该锁
  //可用，则获取，返回true
  //否则，返回false
  public abstract boolean tryLock();
  
  //一定时间内尝试获取锁，否则抛出异常
  public abstract boolean tryLock(long paramLong, TimeUnit paramTimeUnit) throws InterruptedException;
  
  //解锁
  public abstract void unlock();
  
  //返回锁的条件对象
  public abstract Condition newCondition();
}