org.apache.cocoon.components.store
Class MRUMemoryStore

java.lang.Object
  |
  +--org.apache.avalon.framework.logger.AbstractLoggable
        |
        +--org.apache.cocoon.components.store.MRUMemoryStore

All Implemented Interfaces:

org.apache.avalon.framework.component.Component, org.apache.avalon.framework.component.Composable, org.apache.avalon.framework.configuration.Configurable, org.apache.avalon.framework.context.Contextualizable, org.apache.avalon.framework.activity.Disposable, org.apache.avalon.framework.logger.Loggable, Store, org.apache.avalon.framework.thread.ThreadSafe

public final class MRUMemoryStore

extends org.apache.avalon.framework.logger.AbstractLoggable

implements Store, org.apache.avalon.framework.configuration.Configurable, org.apache.avalon.framework.thread.ThreadSafe, org.apache.avalon.framework.component.Composable, org.apache.avalon.framework.activity.Disposable, org.apache.avalon.framework.context.Contextualizable

This class provides a cache algorithm for the requested documents. It combines a HashMap and a LinkedList to create a so called MRU (Most Recently Used) cache. The idea was taken from the "Writing Advanced Application Tutorial" from javasoft. Many thanx to the writers!

Author:

Gerhard Froehlich, Davanum Srinivas

Fields inherited from interface org.apache.cocoon.components.store.Store

ROLE

Constructor Summary

MRUMemoryStore()

Method Summary

void	compose(org.apache.avalon.framework.component.ComponentManager manager) Get components of the ComponentManager
void	configure(org.apache.avalon.framework.configuration.Configuration conf) Initialize the MRUMemoryStore.
boolean	containsKey(java.lang.Object key) Indicates if the given key is associated to a contained object.
void	contextualize(org.apache.avalon.framework.context.Context context) Get the context
void	dispose() Dispose the component
void	free() Frees some of the fast memory used by this store.
java.lang.Object	get(java.lang.Object key) Get the object associated to the given unique key.
void	hold(java.lang.Object key, java.lang.Object value) This method holds the requested object in a HashMap combined with a LinkedList to create the MRU.
java.util.Enumeration	keys() Returns the list of used keys as an Enumeration.
void	remove(java.lang.Object key) Remove the object associated to the given key.
void	store(java.lang.Object key, java.lang.Object value) Store the given object in a persistent state.

Methods inherited from class org.apache.avalon.framework.logger.AbstractLoggable

getLogger, setLogger, setupLogger, setupLogger, setupLogger

Methods inherited from class java.lang.Object

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

Constructor Detail

MRUMemoryStore

public MRUMemoryStore()

Method Detail

compose

public void compose(org.apache.avalon.framework.component.ComponentManager manager)
             throws org.apache.avalon.framework.component.ComponentException

Get components of the ComponentManager

Specified by:

compose in interface org.apache.avalon.framework.component.Composable

Parameters:

the - ComponentManager

contextualize

public void contextualize(org.apache.avalon.framework.context.Context context)
                   throws org.apache.avalon.framework.context.ContextException

Get the context

Specified by:

contextualize in interface org.apache.avalon.framework.context.Contextualizable

Parameters:

the - Context of the application

configure

public void configure(org.apache.avalon.framework.configuration.Configuration conf)
               throws org.apache.avalon.framework.configuration.ConfigurationException

Initialize the MRUMemoryStore. A few options can be used :

• maxobjects = how many objects will be stored in memory (Default: 10 objects)
• filesystem = use filesystem storage to keep object persistent (Default: false)

Specified by:

configure in interface org.apache.avalon.framework.configuration.Configurable

Parameters:

the - Configuration of the application

Throws:

org.apache.avalon.framework.configuration.ConfigurationException -

dispose

public void dispose()

Dispose the component

Specified by:

dispose in interface org.apache.avalon.framework.activity.Disposable

store

public void store(java.lang.Object key,
                  java.lang.Object value)

Store the given object in a persistent state. It is up to the caller to ensure that the key has a persistent state across different JVM executions.

Specified by:

store in interface Store

Parameters:

the - key for the object to store

the - object to store

hold

public void hold(java.lang.Object key,
                 java.lang.Object value)

This method holds the requested object in a HashMap combined with a LinkedList to create the MRU. It also stores objects onto the filesystem if configured.

Specified by:

hold in interface Store

Parameters:

the - key of the object to be stored

the - object to be stored

get

public java.lang.Object get(java.lang.Object key)

Get the object associated to the given unique key.

Specified by:

get in interface Store

Parameters:

the - key of the requested object

Returns:

the requested object

remove

public void remove(java.lang.Object key)

Remove the object associated to the given key.

Specified by:

remove in interface Store

Parameters:

the - key of to be removed object

containsKey

public boolean containsKey(java.lang.Object key)

Indicates if the given key is associated to a contained object.

Specified by:

containsKey in interface Store

Parameters:

the - key of the object

Returns:

true if the key exists

keys

public java.util.Enumeration keys()

Returns the list of used keys as an Enumeration.

Specified by:

keys in interface Store

Returns:

the enumeration of the cache

free

public void free()

Frees some of the fast memory used by this store. It removes the last element in the store.

Specified by:

free in interface Store