com.googlecode.hibernate.memcached
Class MemcachedCache

java.lang.Object
  com.googlecode.hibernate.memcached.MemcachedCache

All Implemented Interfaces:

org.hibernate.cache.Cache

public class MemcachedCache
extends Object
implements org.hibernate.cache.Cache

Wrapper around MemcachedClient instance to provide the bridge between Hiberante and Memcached. Uses the regionName given by Hibernate via the MemcachedCacheProvider when generating cache keys. All cache operations rely on using a KeyStrategy to generate cache keys for use in memcached.

Support for the clear() operation is disabled by default.
There is no way for this instance of MemcachedCache to know what cache values to "clear" in a given Memcached instance. Clear functionality is implemented by incrementing a "clearIndex" value that is always included in the cache-key generation. When clear is called the memcached increment function is used to increment the global clean index. When clear is enabled, every cache action taken starts with a call to memcached to 'get' the clearIndex counter. That value is then applied to the cache key for the cache operation being taken. When the clearIndex is incremented this causes the MemcachedCache to generate different cache-keys than it was before. This results in previously cached data being abandoned in the cache, and left for memcached to deal with.

For these reasons it is not recommended to rely on clear() as a regular production functionality, it is very expensive and generally not very useful anyway.

The MemcachedCache treats Hibernate cache regions as namespaces in Memcached. For more information see the memcached FAQ.

Author:

Ray Krueger

Field Summary

static Integer

DOGPILE_TOKEN

Constructor Summary

MemcachedCache(String regionName, Memcache memcachedClient)

Method Summary

void	clear() Clear functionality is disabled by default.
void	destroy()
Object	get(Object key)
int	getCacheTimeSeconds()
double	getDogpilePreventionExpirationFactor()
long	getElementCountInMemory()
long	getElementCountOnDisk()
KeyStrategy	getKeyStrategy()
String	getRegionName()
long	getSizeInMemory()
int	getTimeout()
boolean	isClearSupported()
boolean	isDogpilePreventionEnabled()
void	lock(Object key)
long	nextTimestamp()
void	put(Object key, Object value)
Object	read(Object key)
void	remove(Object key)
void	setCacheTimeSeconds(int cacheTimeSeconds)
void	setClearSupported(boolean clearSupported)
void	setDogpilePreventionEnabled(boolean dogpilePreventionEnabled)
void	setDogpilePreventionExpirationFactor(double dogpilePreventionExpirationFactor)
void	setKeyStrategy(KeyStrategy keyStrategy)
Map<?,?>	toMap()
String	toString()
void	unlock(Object key)
void	update(Object key, Object value)

Methods inherited from class java.lang.Object

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

Field Detail

DOGPILE_TOKEN

public static final Integer DOGPILE_TOKEN

Constructor Detail

MemcachedCache

public MemcachedCache(String regionName,
                      Memcache memcachedClient)

Method Detail

getCacheTimeSeconds

public int getCacheTimeSeconds()

setCacheTimeSeconds

public void setCacheTimeSeconds(int cacheTimeSeconds)

isClearSupported

public boolean isClearSupported()

setClearSupported

public void setClearSupported(boolean clearSupported)

isDogpilePreventionEnabled

public boolean isDogpilePreventionEnabled()

setDogpilePreventionEnabled

public void setDogpilePreventionEnabled(boolean dogpilePreventionEnabled)

getDogpilePreventionExpirationFactor

public double getDogpilePreventionExpirationFactor()

setDogpilePreventionExpirationFactor

public void setDogpilePreventionExpirationFactor(double dogpilePreventionExpirationFactor)

read

public Object read(Object key)
            throws org.hibernate.cache.CacheException

Specified by:

read in interface org.hibernate.cache.Cache

Throws:

org.hibernate.cache.CacheException

get

public Object get(Object key)
           throws org.hibernate.cache.CacheException

Specified by:

get in interface org.hibernate.cache.Cache

Throws:

org.hibernate.cache.CacheException

put

public void put(Object key,
                Object value)
         throws org.hibernate.cache.CacheException

Specified by:

put in interface org.hibernate.cache.Cache

Throws:

org.hibernate.cache.CacheException

update

public void update(Object key,
                   Object value)
            throws org.hibernate.cache.CacheException

Specified by:

update in interface org.hibernate.cache.Cache

Throws:

org.hibernate.cache.CacheException

remove

public void remove(Object key)
            throws org.hibernate.cache.CacheException

Specified by:

remove in interface org.hibernate.cache.Cache

Throws:

org.hibernate.cache.CacheException

clear

public void clear()
           throws org.hibernate.cache.CacheException

Clear functionality is disabled by default. Read this class's javadoc for more detail.

Specified by:

clear in interface org.hibernate.cache.Cache

Throws:

org.hibernate.cache.CacheException

See Also:

MemcachedCache

destroy

public void destroy()
             throws org.hibernate.cache.CacheException

Specified by:

destroy in interface org.hibernate.cache.Cache

Throws:

org.hibernate.cache.CacheException

lock

public void lock(Object key)
          throws org.hibernate.cache.CacheException

Specified by:

lock in interface org.hibernate.cache.Cache

Throws:

org.hibernate.cache.CacheException

unlock

public void unlock(Object key)
            throws org.hibernate.cache.CacheException

Specified by:

unlock in interface org.hibernate.cache.Cache

Throws:

org.hibernate.cache.CacheException

nextTimestamp

public long nextTimestamp()

Specified by:

nextTimestamp in interface org.hibernate.cache.Cache

getTimeout

public int getTimeout()

Specified by:

getTimeout in interface org.hibernate.cache.Cache

getRegionName

public String getRegionName()

Specified by:

getRegionName in interface org.hibernate.cache.Cache

getSizeInMemory

public long getSizeInMemory()

Specified by:

getSizeInMemory in interface org.hibernate.cache.Cache

getElementCountInMemory

public long getElementCountInMemory()

Specified by:

getElementCountInMemory in interface org.hibernate.cache.Cache

getElementCountOnDisk

public long getElementCountOnDisk()

Specified by:

getElementCountOnDisk in interface org.hibernate.cache.Cache

toMap

public Map<?,?> toMap()

Specified by:

toMap in interface org.hibernate.cache.Cache

toString

public String toString()

Overrides:

toString in class Object

getKeyStrategy

public KeyStrategy getKeyStrategy()

setKeyStrategy

public void setKeyStrategy(KeyStrategy keyStrategy)