org.metasyntactic.thread.concurrent
Class WriterPreferenceReadWriteLock

java.lang.Object
  |
  +--org.metasyntactic.thread.concurrent.WriterPreferenceReadWriteLock

All Implemented Interfaces:

ReadWriteLock

Direct Known Subclasses:

ReaderPreferenceReadWriteLock

public class WriterPreferenceReadWriteLock

extends java.lang.Object

implements ReadWriteLock

A ReadWriteLock that prefers waiting writers over waiting readers when there is contention. This class is adapted from the versions described in CPJ, improving on the ones there a bit by segregating reader and writer wait queues, which is typically more efficient.

The locks are NOT reentrant. In particular, even though it may appear to usually work OK, a thread holding a read lock should not attempt to re-acquire it. Doing so risks lockouts when there are also waiting writers.

Field Summary

protected java.lang.Thread

activeWriter A reference to the actual writer currently writing

Constructor Summary

WriterPreferenceReadWriteLock()

Method Summary

Monitor	readLock() Get's this Lock's read monitor.
Monitor	writeLock() Get's this Lock's writer monitor.

Methods inherited from class java.lang.Object

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

Field Detail

activeWriter

protected java.lang.Thread activeWriter

A reference to the actual writer currently writing

Constructor Detail

WriterPreferenceReadWriteLock

public WriterPreferenceReadWriteLock()

Method Detail

writeLock

public Monitor writeLock()

Get's this Lock's writer monitor. The caller must then call .acquire() on thie monitor before they begin writing

Specified by:

writeLock in interface ReadWriteLock

Returns:

The write lock monitor

readLock

public Monitor readLock()

Get's this Lock's read monitor. The caller must then call .acquire() on thie monitor before they begin Reading

Specified by:

readLock in interface ReadWriteLock

Returns:

The read monitor