Package org.apache.fulcrum.cache.impl
Class DefaultGlobalCacheService
java.lang.Object
org.apache.avalon.framework.logger.AbstractLogEnabled
org.apache.fulcrum.cache.impl.DefaultGlobalCacheService
- All Implemented Interfaces:
Runnable
,org.apache.avalon.framework.activity.Disposable
,org.apache.avalon.framework.activity.Initializable
,org.apache.avalon.framework.configuration.Configurable
,org.apache.avalon.framework.logger.LogEnabled
,org.apache.avalon.framework.thread.ThreadSafe
,GlobalCacheService
public class DefaultGlobalCacheService
extends org.apache.avalon.framework.logger.AbstractLogEnabled
implements GlobalCacheService, Runnable, org.apache.avalon.framework.configuration.Configurable, org.apache.avalon.framework.activity.Initializable, org.apache.avalon.framework.activity.Disposable, org.apache.avalon.framework.thread.ThreadSafe
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.
- Version:
- $Id$
- Author:
- Dave Bryson, Jon S. Stevens, John Thorhauer, Henning P. Schmiedehausen, Eric Pugh, Peter CourefreshableCachedObjectux
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Field Summary
FieldsModifier and TypeFieldDescriptionprotected ConcurrentHashMap
<String, CachedObject<?>> The cache.static final String
The property for the Cache check frequencystatic final long
Cache check frequency in Millis (1000 Millis = 1 second).static final int
Initial size of hash table Value must be > 0.static final String
The property for the InitalCacheSizeFields inherited from interface org.apache.fulcrum.cache.GlobalCacheService
ROLE
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescription<T> void
addObject
(String objectId, CachedObject<T> object) Adds an object to the cache.void
Iterate through the cache and remove or refresh stale objects.void
configure
(org.apache.avalon.framework.configuration.Configuration conf) Avalon component lifecycle methodvoid
dispose()
Avalon component lifecycle methodvoid
Flush the cache of all objects.long
Get the Cache Check Frequency in millisecondsList
<CachedObject<?>> Returns a copy of the non-expired CachedObjects in the cache as a list.int
Returns the current size of the cache.getKeys()
Returns a copy of keys to objects in the cache as a list.int
Returns the number of objects currently stored in the cache<T> CachedObject
<T> Returns an item from the cache. /** Returns an item from the cache.void
Avalon component lifecycle methodvoid
removeObject
(String objectId) Removes an object from the cache.void
run()
Circle through the cache and remove stale objects.Methods inherited from class org.apache.avalon.framework.logger.AbstractLogEnabled
enableLogging, getLogger, setupLogger, setupLogger, setupLogger
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Field Details
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DEFAULT_INITIAL_CACHE_SIZE
public static final int DEFAULT_INITIAL_CACHE_SIZEInitial size of hash table Value must be > 0. Default = 20- See Also:
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INITIAL_CACHE_SIZE
The property for the InitalCacheSize- See Also:
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CACHE_CHECK_FREQUENCY
The property for the Cache check frequency- See Also:
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DEFAULT_CACHE_CHECK_FREQUENCY
public static final long DEFAULT_CACHE_CHECK_FREQUENCYCache check frequency in Millis (1000 Millis = 1 second). Value must be > 0. Default = 5 seconds- See Also:
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cache
The cache.
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Constructor Details
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DefaultGlobalCacheService
public DefaultGlobalCacheService()
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Method Details
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getCacheCheckFrequency
public long getCacheCheckFrequency()Get the Cache Check Frequency in milliseconds- Returns:
- the time between two cache check runs in milliseconds
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getObject
Returns an item from the cache. /** Returns an item from the cache. RefreshableCachedObject will be refreshed if it is expired and not untouched.- Specified by:
getObject
in interfaceGlobalCacheService
- Type Parameters:
T
- type of object to return- Parameters:
objectId
- 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.
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addObject
Adds an object to the cache.- Specified by:
addObject
in interfaceGlobalCacheService
- Type Parameters:
T
- type of object to add- Parameters:
objectId
- The key to store the object by.object
- The object to cache.
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removeObject
Removes an object from the cache.- Specified by:
removeObject
in interfaceGlobalCacheService
- Parameters:
objectId
- The String id for the object.
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getKeys
Returns a copy of keys to objects in the cache as a list. Note that keys to expired objects are not returned.- Specified by:
getKeys
in interfaceGlobalCacheService
- Returns:
- A List of
String
's representing the keys to objects in the cache.
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getCachedObjects
Returns a copy of the non-expired CachedObjects in the cache as a list.- Specified by:
getCachedObjects
in interfaceGlobalCacheService
- Returns:
- A List of
CachedObject
objects held in the cache
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run
public void run()Circle through the cache and remove stale objects. Frequency is determined by the cacheCheckFrequency property. -
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 interfaceGlobalCacheService
- Returns:
- int number of object in the cache
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getCacheSize
Returns the current size of the cache.- Specified by:
getCacheSize
in interfaceGlobalCacheService
- Returns:
- int representing current cache size in number of bytes
- Throws:
IOException
- if unable to return cache size
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flushCache
public void flushCache()Flush the cache of all objects.- Specified by:
flushCache
in interfaceGlobalCacheService
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configure
public void configure(org.apache.avalon.framework.configuration.Configuration conf) throws org.apache.avalon.framework.configuration.ConfigurationException Avalon component lifecycle method- Specified by:
configure
in interfaceorg.apache.avalon.framework.configuration.Configurable
- Throws:
org.apache.avalon.framework.configuration.ConfigurationException
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initialize
Avalon component lifecycle method- Specified by:
initialize
in interfaceorg.apache.avalon.framework.activity.Initializable
- Throws:
Exception
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dispose
public void dispose()Avalon component lifecycle method- Specified by:
dispose
in interfaceorg.apache.avalon.framework.activity.Disposable
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