com.communote.server.external.hibernate

Class SingletonEhCacheProvider

java.lang.Object

com.communote.server.external.hibernate.SingletonEhCacheProvider

All Implemented Interfaces:

org.hibernate.cache.CacheProvider

public class SingletonEhCacheProvider
extends Object
implements org.hibernate.cache.CacheProvider

Custom EhCacheProvider which ensures that the correct disk store path is used and the cache manager can be shared between Hibernate and Communote.

Additionally this provider defines a mapping from an Hibernate cache region to the actual EhCache. This mapping was included to circumvent some shortcomings of the default behavior which would map each cache region to a distinctive EhCache. Especially in clustered environments this is not desired since EhCache creates additional threads for each cache to manage change distributions.
We could have used other names for the Hibernate cache regions (e.g. "UserGroupCache" instead of qualified class name) in the hbm.xml files (after extending AndroMDA to support it) but this has a disadvantage. For each cache region Hibernate creates one cache object representing it. This object is an instance of a class implementing the CacheConcurrencyStrategy interface. One of the implementations is the ReadWriteCache which uses method based synchronization to support an isolation level close to repeatable read. When grouping a lot of entity and collection caches in a region that uses the ReadWriteCache strategy we might get a negative impact on the performance since the get method to retrieve a cached item is synchronized too. By incorporating our own mapping we are reducing the frequency of concurrent gets on the same Hibernate cache because entities and collection got their own region.

Parts of the implementation are taken from net.sf.ehcache.hibernate.SingletonEhCacheProvider

Author:

Communote GmbH - http://www.communote.com/

Constructor Summary

Constructors

Constructor and Description
SingletonEhCacheProvider() Create a new provider and prepare the region mapping.

Method Summary

Modifier and Type	Method and Description
org.hibernate.cache.Cache	buildCache(String name, Properties properties)
boolean	isMinimalPutsEnabledByDefault()
long	nextTimestamp()
void	start(Properties properties)
void	stop()

Methods inherited from class java.lang.Object

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

Constructor Detail

SingletonEhCacheProvider

public SingletonEhCacheProvider()

Create a new provider and prepare the region mapping.

Method Detail

buildCache

public org.hibernate.cache.Cache buildCache(String name,
                                            Properties properties)
                                     throws org.hibernate.cache.CacheException

Specified by:

buildCache in interface org.hibernate.cache.CacheProvider

Throws:

org.hibernate.cache.CacheException

isMinimalPutsEnabledByDefault

public boolean isMinimalPutsEnabledByDefault()

Specified by:

isMinimalPutsEnabledByDefault in interface org.hibernate.cache.CacheProvider

nextTimestamp

public long nextTimestamp()

Specified by:

nextTimestamp in interface org.hibernate.cache.CacheProvider

start

public void start(Properties properties)
           throws org.hibernate.cache.CacheException

Specified by:

start in interface org.hibernate.cache.CacheProvider

Throws:

org.hibernate.cache.CacheException

stop

public void stop()

Specified by:

stop in interface org.hibernate.cache.CacheProvider