org.apache.turbine.services.cache
Class TurbineGlobalCacheService

java.lang.Object
  org.apache.turbine.services.BaseInitable
      org.apache.turbine.services.BaseService
          org.apache.turbine.services.TurbineBaseService
              org.apache.turbine.services.cache.TurbineGlobalCacheService

All Implemented Interfaces:

GlobalCacheService, Initable, java.lang.Runnable, Service

public class TurbineGlobalCacheService

extends TurbineBaseService

implements GlobalCacheService, java.lang.Runnable

This Service functions as a Global Cache. A global cache is a good place to store items that you may need to access often but don't necessarily need (or want) to fetch from the database everytime. A good example would be a look up table of States that you store in a database and use throughout your application. Since information about States doesn't change very often, you could store this information in the Global Cache and decrease the overhead of hitting the database everytime you need State information. The following properties are needed to configure this service:

 services.GlobalCacheService.classname=org.apache.turbine.services.cache.TurbineGlobalCacheService
 services.GlobalCacheService.cache.initial.size=20
 services.GlobalCacheService.cache.check.frequency=5000
 

classname

the classname of this service

cache.initial.size

Initial size of hash table use to store cached objects. If this property is not present, the default value is 20

cache.check.frequency

Cache check frequency in Millis (1000 Millis = 1 second). If this property is not present, the default value is 5000

Version:

$Id: TurbineGlobalCacheService.java 534527 2007-05-02 16:10:59Z tv $

Author:

Dave Bryson, Jon S. Stevens, John Thorhauer, Henning P. Schmiedehausen

Field Summary

static java.lang.String	CACHE_CHECK_FREQUENCY The property for the Cache check frequency
static long	DEFAULT_CACHE_CHECK_FREQUENCY Cache check frequency in Millis (1000 Millis = 1 second).
static int	DEFAULT_INITIAL_CACHE_SIZE Initial size of hash table Value must be > 0.
static java.lang.String	INITIAL_CACHE_SIZE The property for the InitalCacheSize

Fields inherited from class org.apache.turbine.services.BaseService

configuration, name, serviceBroker

Fields inherited from class org.apache.turbine.services.BaseInitable

initableBroker, isInitialized

Fields inherited from interface org.apache.turbine.services.cache.GlobalCacheService

SERVICE_NAME

Constructor Summary

TurbineGlobalCacheService()
Constructor.

Method Summary

void	addObject(java.lang.String id, CachedObject o) Adds an object to the cache.
void	clearCache() Iterate through the cache and remove or refresh stale objects.
void	flushCache() Flush the cache of all objects.
int	getCacheSize() Returns the current size of the cache.
int	getNumberOfObjects() Returns the number of objects currently stored in the cache
CachedObject	getObject(java.lang.String id) Returns an item from the cache.
void	init() Called the first time the Service is used.
void	removeObject(java.lang.String id) Removes an object from the cache.
void	run() Circle through the cache and remove stale objects.

Methods inherited from class org.apache.turbine.services.TurbineBaseService

init, init, init, shutdown

Methods inherited from class org.apache.turbine.services.BaseService

getConfiguration, getName, getProperties, getServiceBroker, setName, setServiceBroker

Methods inherited from class org.apache.turbine.services.BaseInitable

getInit, getInitableBroker, setInit, setInitableBroker

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.turbine.services.Service

getConfiguration, getName, getProperties, setName, setServiceBroker

Methods inherited from interface org.apache.turbine.services.Initable

getInit, init, setInitableBroker, shutdown

Field Detail

DEFAULT_INITIAL_CACHE_SIZE

public static final int DEFAULT_INITIAL_CACHE_SIZE

Initial size of hash table Value must be > 0. Default = 20

See Also:

Constant Field Values

INITIAL_CACHE_SIZE

public static final java.lang.String INITIAL_CACHE_SIZE

The property for the InitalCacheSize

See Also:

Constant Field Values

CACHE_CHECK_FREQUENCY

public static final java.lang.String CACHE_CHECK_FREQUENCY

The property for the Cache check frequency

See Also:

Constant Field Values

DEFAULT_CACHE_CHECK_FREQUENCY

public static final long DEFAULT_CACHE_CHECK_FREQUENCY

Cache check frequency in Millis (1000 Millis = 1 second). Value must be > 0. Default = 5 seconds

See Also:

Constant Field Values

Constructor Detail

TurbineGlobalCacheService

public TurbineGlobalCacheService()

Constructor.

Method Detail

init

public void init()
          throws InitializationException

Called the first time the Service is used.

Specified by:

init in interface Initable

Overrides:

init in class TurbineBaseService

Throws:

InitializationException

getObject

public CachedObject getObject(java.lang.String id)
                       throws ObjectExpiredException

Returns an item from the cache. RefreshableCachedObject will be refreshed if it is expired and not untouched.

Specified by:

getObject in interface GlobalCacheService

Parameters:

id - The key of the stored object.

Returns:

The object from the cache.

Throws:

ObjectExpiredException - when either the object is not in the cache or it has expired.

addObject

public void addObject(java.lang.String id,
                      CachedObject o)

Adds an object to the cache.

Specified by:

addObject in interface GlobalCacheService

Parameters:

id - The key to store the object by.

o - The object to cache.

removeObject

public void removeObject(java.lang.String id)

Removes an object from the cache.

Specified by:

removeObject in interface GlobalCacheService

Parameters:

id - The String id for the object.

run

public void run()

Circle through the cache and remove stale objects. Frequency is determined by the cacheCheckFrequency property.

Specified by:

run in interface java.lang.Runnable

clearCache

public void clearCache()

Iterate through the cache and remove or refresh stale objects.

getNumberOfObjects

public int getNumberOfObjects()

Returns the number of objects currently stored in the cache

Specified by:

getNumberOfObjects in interface GlobalCacheService

Returns:

int number of object in the cache

getCacheSize

public int getCacheSize()
                 throws java.io.IOException

Returns the current size of the cache.

Specified by:

getCacheSize in interface GlobalCacheService

Returns:

int representing current cache size in number of bytes

Throws:

java.io.IOException

flushCache

public void flushCache()

Flush the cache of all objects.

Specified by:

flushCache in interface GlobalCacheService