net.wotonomy.foundation
Class NSMultiReaderLock

java.lang.Object
  EDU.oswego.cs.dl.util.concurrent.WriterPreferenceReadWriteLock
      EDU.oswego.cs.dl.util.concurrent.ReentrantWriterPreferenceReadWriteLock
          net.wotonomy.foundation.NSMultiReaderLock

All Implemented Interfaces:

EDU.oswego.cs.dl.util.concurrent.ReadWriteLock, NSLocking

public class NSMultiReaderLock
extends EDU.oswego.cs.dl.util.concurrent.ReentrantWriterPreferenceReadWriteLock
implements NSLocking

A Read-Write lock that allows unlimited number of calling threads to acquire read locks, but only one thread to acquire a write lock. It is also reentrant, allowing each thread to re-acquire it's lock recursively. For that reason it is somewhat slower, as there is a hash lookup when attempting to acquire and release reader locks. Of course a writer lock is quite a bit slower than a reader lock. A write lock is mutally exclusive with read locks, though a thread that has obtained a read-lock may be promoted to a write lock and vice versa when conditions permit.

Version:

$Revision: 893 $

Author:

cgruber@israfil.net, $Author: cgruber $

Nested Class Summary

Nested classes/interfaces inherited from class EDU.oswego.cs.dl.util.concurrent.WriterPreferenceReadWriteLock

EDU.oswego.cs.dl.util.concurrent.WriterPreferenceReadWriteLock.ReaderLock, EDU.oswego.cs.dl.util.concurrent.WriterPreferenceReadWriteLock.Signaller, EDU.oswego.cs.dl.util.concurrent.WriterPreferenceReadWriteLock.WriterLock

Field Summary

Fields inherited from class EDU.oswego.cs.dl.util.concurrent.ReentrantWriterPreferenceReadWriteLock

IONE, readers_, writeHolds_

Fields inherited from class EDU.oswego.cs.dl.util.concurrent.WriterPreferenceReadWriteLock

activeReaders_, activeWriter_, readerLock_, waitingReaders_, waitingWriters_, writerLock_

Fields inherited from interface net.wotonomy.foundation.NSLocking

OneCentury, OneDay, OneHour, OneMinute, OneSecond, OneWeek, OneYear

Constructor Summary

NSMultiReaderLock()

Method Summary

protected java.lang.String	_padString(long l, int i)
protected java.lang.String	_padString(java.lang.String s, int i, boolean flag)
void	lock()
void	lockForReading()
void	lockForWriting()
void	retrieveReaderLocks()
void	suspendReaderLocks()
java.lang.String	toString()
boolean	tryLockForReading()
boolean	tryLockForWriting()
void	unlock()
void	unlockForReading()
void	unlockForWriting()

Methods inherited from class EDU.oswego.cs.dl.util.concurrent.ReentrantWriterPreferenceReadWriteLock

allowReader, endRead, endWrite, startRead, startWrite

Methods inherited from class EDU.oswego.cs.dl.util.concurrent.WriterPreferenceReadWriteLock

cancelledWaitingReader, cancelledWaitingWriter, readLock, startReadFromNewReader, startReadFromWaitingReader, startWriteFromNewWriter, startWriteFromWaitingWriter, writeLock

Methods inherited from class java.lang.Object

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

Constructor Detail

NSMultiReaderLock

public NSMultiReaderLock()

Method Detail

lockForReading

public void lockForReading()

unlockForReading

public void unlockForReading()

lock

public void lock()

Specified by:

lock in interface NSLocking

lockForWriting

public void lockForWriting()

unlock

public void unlock()

Specified by:

unlock in interface NSLocking

unlockForWriting

public void unlockForWriting()

suspendReaderLocks

public void suspendReaderLocks()

See Also:

com.webobjects.foundation.NSMultiReaderLock#suspendReaderLock()

retrieveReaderLocks

public void retrieveReaderLocks()

See Also:

com.webobjects.foundation.NSMultiReaderLock#retrieveReaderLock()

tryLockForWriting

public boolean tryLockForWriting()

tryLockForReading

public boolean tryLockForReading()

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

_padString

protected java.lang.String _padString(long l,
                                      int i)

_padString

protected java.lang.String _padString(java.lang.String s,
                                      int i,
                                      boolean flag)