org.metasyntactic.thread.concurrent
Interface ReadWriteLock

All Known Implementing Classes:
WriterPreferenceReadWriteLock

public interface ReadWriteLock

ReadWriteLocks maintain a pair of associated locks. The readLock may be held simultanously by multiple reader threads, so long as there are no writers. The writeLock is exclusive. ReadWrite locks are generally preferable to plain Monitor locks or synchronized methods in cases where:

Different implementation classes differ in policies surrounding which threads to prefer when there is contention. By far, the most commonly useful policy is WriterPreferenceReadWriteLock. The other implementations are targeted for less common, niche applications.

Standard usage:

 class X {
   ReadWriteLock rw;
   // ...

   public void read() throws InterruptedException {
     rw.readLock().acquire();
     try {
       // ... do the read
     }
     finally {
       rw.readlock().release()
     }
   }


   public void write() throws InterruptedException {
     rw.writeLock().acquire();
     try {
       // ... do the write
     }
     finally {
       rw.writelock().release()
     }
   }
 }
 

See Also:
Monitor

Method Summary
 Monitor readLock()
          get the readLock
 Monitor writeLock()
          get the writeLock
 

Method Detail

readLock

public Monitor readLock()
get the readLock

Returns:
A lock that must be acquired before reading can occur

writeLock

public Monitor writeLock()
get the writeLock

Returns:
The lock that must be acquired before writing can occurr