org.jboss.util
Interface CachePolicy

All Superinterfaces:

Service

All Known Subinterfaces:

EnterpriseContextCachePolicy

All Known Implementing Classes:

LRUCachePolicy, TimedCachePolicy

public interface CachePolicy

extends Service

Interface that specifies a policy for caches.

Implementation classes can implement a LRU policy, a random one, a MRU one, or any other suitable policy.

Version:

$Revision: 1.2 $

Author:

Simone Bordet (simone.bordet@compaq.com)

Method Summary

void	flush() Flushes the cached objects from the cache.
java.lang.Object	get(java.lang.Object key) Returns the object paired with the specified key if it's present in the cache, otherwise must return null.
void	insert(java.lang.Object key, java.lang.Object object) Inserts the specified object into the cache following the implemented policy.
java.lang.Object	peek(java.lang.Object key) Returns the object paired with the specified key if it's present in the cache, otherwise must return null.
void	remove(java.lang.Object key) Remove the cached object paired with the specified key.

Methods inherited from interface org.jboss.util.Service

destroy, init, start, stop

Method Detail

get

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

Returns the object paired with the specified key if it's present in the cache, otherwise must return null.
Implementations of this method must have complexity of order O(1). Differently from peek(java.lang.Object) this method not only return whether the object is present in the cache or not, but also applies the implemented policy that will "refresh" the cached object in the cache, because this cached object was really requested.

Parameters:

key - the key paired with the object

See Also:

peek(java.lang.Object)

peek

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

Returns the object paired with the specified key if it's present in the cache, otherwise must return null.
Implementations of this method must have complexity of order O(1). This method should not apply the implemented caching policy to the object paired with the given key, so that a client can query if an object is cached without "refresh" its cache status. Real requests for the object must be done using get(java.lang.Object).

Parameters:

key - the key paired with the object

See Also:

get(java.lang.Object)

insert

public void insert(java.lang.Object key,
                   java.lang.Object object)

Inserts the specified object into the cache following the implemented policy.
Implementations of this method must have complexity of order O(1).

Parameters:

key - the key paired with the object

object - the object to cache

See Also:

remove(java.lang.Object)

remove

public void remove(java.lang.Object key)

Remove the cached object paired with the specified key.
Implementations of this method must have complexity of order O(1).

Parameters:

key - the key paired with the object

See Also:

insert(java.lang.Object, java.lang.Object)

flush

public void flush()

Flushes the cached objects from the cache.