uwcse.location.objects
Class MultiReadSingleWriteLock

java.lang.Object
  |
  +--uwcse.location.objects.MultiReadSingleWriteLock

public class MultiReadSingleWriteLock

extends Object

This class implements a reader-writer lock allowing parallel reads but FIFO serialized atomic writes. Reads have priority in that when an active write releases its lock, pending reads will execute before other pending writes.

Methods should use a try-finally structure to request and release locks to avoid erroneous starvation or deadlock.

Multiple locks and deadlock: Note that in this implementation, attempts by a thread to acquire another lock when it already holds one will very likely result in deadlock.

Version:

$Revision: 1.6 $

Author:

Jeffrey Hightower

Nested Class Summary
static class	MultiReadSingleWriteLock.UnitTest           A unit test for the lock.

 

Constructor Summary

MultiReadSingleWriteLock()           Create a multi-reader single-writer resource lock.

 

Method Summary
void	acquireReadLock()           Requests the read lock and block until a read operation can be performed safely.
void	acquireWriteLock()           Request the write lock and block until a write operation can be performed safely.
void	releaseReadLock()           Release a previously acquired read lock.
void	releaseWriteLock()           Release a previously acquired write lock.

 

Methods inherited from class java.lang.Object

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

 

Constructor Detail

MultiReadSingleWriteLock

public MultiReadSingleWriteLock()

Create a multi-reader single-writer resource lock.

acquireReadLock

public void acquireReadLock()

Requests the read lock and block until a read operation can be performed safely. This call must be followed by a call to releaseReadLock() when the read operation completes (typically in a finally{} block).

See Also:

releaseReadLock()

releaseReadLock

public void releaseReadLock()

Release a previously acquired read lock.

See Also:

acquireReadLock()

acquireWriteLock

public void acquireWriteLock()

Request the write lock and block until a write operation can be performed safely. Write requests execute FIFO but pending read requests have priority. When the write is finished, this call must be followed by a call to releaseWriteLock() (typically in a finally{} block).

See Also:

releaseWriteLock()

releaseWriteLock

public void releaseWriteLock()

Release a previously acquired write lock.

See Also:

acquireWriteLock()