org.mmbase.cache
Class CachePolicy

java.lang.Object
  org.mmbase.cache.CachePolicy

All Implemented Interfaces:

Serializable

public abstract class CachePolicy

extends Object

implements Serializable

A CachePolicy object determines for a given object whether it should be cached or not, and how. Code that makes use of a cache should use a CachePolicy object, when available, to determine if the object should be cached or not.

Since:

MMBase 1.8

Version:

$Id: CachePolicy.java,v 1.3 2005/09/23 13:59:26 pierre Exp $

Author:

Pierre van Rooden

See Also:

Serialized Form

Field Summary

static CachePolicy	ALWAYS Standard cache policy that advises to always cache a passed object.
static CachePolicy	NEVER Standard cache policy that advises to never cache a passed object.

Constructor Summary

protected	CachePolicy() Instantiates a new cache policy without registering it
protected	CachePolicy(Object policyKey) Instantiates a new cache policy, and registers it with the given policy key.

Method Summary

abstract boolean	checkPolicy(Object o) Checks whether the policy advises to cache the passed object.
String	getDescription() Returns a description of the policy.
static CachePolicy	getPolicy(Object policyKey) Obtains a cache policy given a policy key.
static void	putPolicy(Object policyKey, CachePolicy policy)

Methods inherited from class java.lang.Object

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

Field Detail

NEVER

public static CachePolicy NEVER

Standard cache policy that advises to never cache a passed object. Accessible with the key "never".

ALWAYS

public static CachePolicy ALWAYS

Standard cache policy that advises to always cache a passed object. Accessible with the key "always".

Constructor Detail

CachePolicy

protected CachePolicy(Object policyKey)

Instantiates a new cache policy, and registers it with the given policy key.

CachePolicy

protected CachePolicy()

Instantiates a new cache policy without registering it

Method Detail

getPolicy

public static CachePolicy getPolicy(Object policyKey)

Obtains a cache policy given a policy key.

Parameters:

policyKey - the key of the cache policy

Returns:

the policy key

Throws:

IllegalArgumentException - if the policy does not exist

putPolicy

public static void putPolicy(Object policyKey,
                             CachePolicy policy)

checkPolicy

public abstract boolean checkPolicy(Object o)

Checks whether the policy advises to cache the passed object.

Parameters:

o - the object to check the cache for

Returns:

true if the policy advises to cache this object, false otherwise.

getDescription

public String getDescription()

Returns a description of the policy.