Package org.geotools.util

Class ObjectCaches

Object

ObjectCaches

public final class ObjectCaches
extends Object

This is facade around several constructs used by GeoTools for internal caching.

This class provides the following services:

• Access to an implementation of "weak", "all" and "none" implementations of ObjectCache.
• The ability to turn a "code" into a good "key" for use with an ObjectCache.
• A Pair data object (think of C STRUCT) for use as a key when storing a value against two objects.

Since:

2.5

Author:

Jody Garnett, Cory Horner

Method Summary

Modifier and Type	Method	Description
static <K,V> ObjectCache<K,V>	chain(ObjectCache<K,V> level1, ObjectCache<K,V> level2)	Create a two level cache, operates as a level1 cache that is willing to obtain values from a (usually shared) level2 cache.
static <K,V> ObjectCache<K,V>	create(String policy, int size)	Utility method used to produce an ObjectCache.
static <K,V> ObjectCache<K,V>	create(Hints hints)	Utility method used to produce cache based on provide Hint
static String	toKey(Citation citation, String code)	Produce a good key based on the privided citaiton and code.
static Object	toKey(Citation citation, String code1, String code2)	Produce a good key based on a pair of codes.

Methods inherited from class Object

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

Method Detail

chain

public static <K,V> ObjectCache<K,V> chain(ObjectCache<K,V> level1,
                                                       ObjectCache<K,V> level2)

Create a two level cache, operates as a level1 cache that is willing to obtain values from a (usually shared) level2 cache.

This functionality is used to tie two ObjectCache implementations together (allowing them to collaborate while focusing on different use cases). The real world example of chaining is in AbstractFindableAuthorityFactory in which:

• create uses: chain( cache, findCache )
• find uses: chain( findCache, cache )

In this manner the find operation does not upset normal cache. It will not create any objects already present in the cache.

Returns:

ObjectCache

create

public static <K,V> ObjectCache<K,V> create(Hints hints)
                                                 throws FactoryRegistryException

Utility method used to produce cache based on provide Hint

Throws:

FactoryRegistryException

create

public static <K,V> ObjectCache<K,V> create(String policy,
                                                        int size)

Utility method used to produce an ObjectCache.

Parameters:

policy - One of "weak", "all", "none", "soft"

size - Used to indicate requested size, exact use depends on policy

Returns:

A new ObjectCache

See Also:

Hints.BUFFER_POLICY

toKey

public static String toKey(Citation citation,
                           String code)

Produce a good key based on the privided citaiton and code. You can think of the citation as being "here" and the code being the "what".

Parameters:

code - Code

Returns:

A good key for use with ObjectCache

toKey

public static Object toKey(Citation citation,
                           String code1,
                           String code2)

Produce a good key based on a pair of codes.

Returns:

A object to use as a key