net.sf.ehcache.constructs.concurrent
Class ConcurrencyUtil

java.lang.Object
  net.sf.ehcache.constructs.concurrent.ConcurrencyUtil

public final class ConcurrencyUtil
extends java.lang.Object

Various bits of black magic garnered from experts on the concurrency-interest@cs.oswego.edu mailing list.

Version:

$Id: ConcurrencyUtil.java 519 2007-07-27 07:11:45Z gregluck $

Author:

Greg Luck

Method Summary

static int	hash(java.lang.Object object) Returns a hash code for non-null Object x.
static int	selectLock(java.lang.Object key, int numberOfLocks) Selects a lock for a key.

Methods inherited from class java.lang.Object

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

Method Detail

hash

public static int hash(java.lang.Object object)

Returns a hash code for non-null Object x.

This function ensures that hashCodes that differ only by constant multiples at each bit position have a bounded number of collisions. (Doug Lea)

Parameters:

object - the object serving as a key

Returns:

the hash code

selectLock

public static int selectLock(java.lang.Object key,
                             int numberOfLocks)
                      throws CacheException

Selects a lock for a key. The same lock is always used for a given key.

Parameters:

key -

Returns:

the selected lock index

Throws:

CacheException