org.jboss.util

Interface CachePolicy

All Known Implementing Classes:

LRUCachePolicy, SynchronizedCachePolicy, TimedCachePolicy

public interface CachePolicy

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:

$Revision$

Method Summary

Modifier and Type	Method and Description
void	create()
void	destroy()
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.
int	size()
void	start()
void	stop()

Method Detail

get

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

Returns:

the object

See Also:

peek(java.lang.Object)

peek

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

Returns:

the object

See Also:

get(java.lang.Object)

insert

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

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

void flush()

Flushes the cached objects from the cache.

size

int size()

Returns:

the size of the cache

create

void create()
     throws java.lang.Exception

Throws:

java.lang.Exception

start

void start()
    throws java.lang.Exception

Throws:

java.lang.Exception

stop

void stop()

destroy

void destroy()