cn.ponfee.disjob.common.lock

类 RedisLock

java.lang.Object

cn.ponfee.disjob.common.lock.RedisLock

所有已实现的接口:

Serializable, Lock

public class RedisLock
extends Object
implements Lock, Serializable

 Distributes lock based redis(unlock使用redis lua script)
 可重入锁的一般场景：当前线程多次调用含有锁操作的函数、当前线程含有锁操作的函数自身调用
 待完善:
   1、获取锁成功的线程 A 定时续期锁：WatchDog
   2、获取锁失败的线程 B 阻塞等待并监听(订阅)事件：subscribe
   3、线程 A 释放锁时发送消息事件通知等待锁的线程B：publish

 
 RedisLockFactory factory = new RedisLockFactory(redisTemplate);

 class X {
   public void m() {
     Lock lock = factory.create("lockKey", 3000);
     lock.lock();  // block until acquire lock or timeout
     try {
       // ... method body
     } finally {
       lock.unlock()
     }
   }
 }

 class Y {
   public void m() {
     Lock lock = factory.create("lockKey", 3000);
     if (!lock.tryLock()) return;
     try {
       // ... method body
     } finally {
       lock.unlock();
     }
   }
 }

 class Z {
   public void m() {
     Lock lock = factory.create("lockKey", 3000);
     // auto timeout release lock
     if (!lock.tryLock(100, TimeUnit.MILLISECONDS)) return;
     try {
       // ... method body
     } finally {
       lock.unlock();
     }
   }
 }
 

作者:

Ponfee

另请参阅:

better implementation: redisson, 序列化表格

方法概要

限定符和类型	方法和说明
void	forceUnlock() Force unlock
boolean	isHeldByCurrentThread() 当前线程是否持有锁 {@code class X { Lock lock = new RedisLock(redisTemplate, "lockKey", 100); // ...
boolean	isLocked() 是否已锁（任何线程）
void	lock() 等待锁直到获取(non interrupt)
void	lockInterruptibly() 等待锁直到获取成功或抛出InterruptedException异常
Condition	newCondition()
boolean	tryLock() 尝试获取锁，成功返回true，失败返回false
boolean	tryLock(long timeout, TimeUnit unit) 尝试获取锁，成功返回true，失败返回false 线程中断则抛出interrupted异常
void	unlock() 释放锁

从类继承的方法 java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

方法详细资料

lock

public void lock()

等待锁直到获取(non interrupt)

指定者:

lock 在接口中 Lock

lockInterruptibly

public void lockInterruptibly()
                       throws InterruptedException

等待锁直到获取成功或抛出InterruptedException异常

指定者:

lockInterruptibly 在接口中 Lock

抛出:

InterruptedException - if call Thread#interrupt

tryLock

public boolean tryLock()

尝试获取锁，成功返回true，失败返回false

指定者:

tryLock 在接口中 Lock

返回:

if true get lock successfully

tryLock

public boolean tryLock(long timeout,
                       TimeUnit unit)
                throws InterruptedException

尝试获取锁，成功返回true，失败返回false
线程中断则抛出interrupted异常

指定者:

tryLock 在接口中 Lock

参数:

timeout - the timeout value

unit - the timeout unit

返回:

true lock successfully

抛出:

InterruptedException - if interrupted

unlock

public void unlock()

释放锁

指定者:

unlock 在接口中 Lock

newCondition

public Condition newCondition()

指定者:

newCondition 在接口中 Lock

isHeldByCurrentThread

public boolean isHeldByCurrentThread()

当前线程是否持有锁

  
     class X {
       Lock lock = new RedisLock(redisTemplate, "lockKey", 100);
       // ...
       public void m() {
         assert !lock.isHeldByCurrentThread();
         lock.lock();
         try {
             // ... method body
         } finally {
             lock.unlock();
         }
       }
     }
  
 

返回:

if true the current thread held locked

isLocked

public boolean isLocked()

是否已锁（任何线程）

返回:

true is locked

forceUnlock

public void forceUnlock()

Force unlock