velosurf.cache
Class Cache

java.lang.Object
  velosurf.cache.Cache

public class Cache
extends java.lang.Object

Cache that keeps fetched instances in memory.

Three modes (defined for <database> or for <entity> in model.xml:

• NO_CACHE (cache='none', the default) : no caching occurs on this entity.
• SOFT_CACHE (cache='soft') : caching occurs as long as memory is ont reclaimed (see the behaviour of java soft references).
• FULL_CACHE (cache='full') : the whole table is loaded into the cache at startup.

For an entity's instances to be cached, the associated table must have a primary key (even if multivalued).

Warning: Velosurf will invalidate entries on single row update and delete queries, but global updates and deletes are not taken into account.

This caching mechanism is meant for straightforward optimizations in read-only or very simple situations, for instance to avoid re-fetching data related to the logged user at each request.

Author:

Claude Brisson

Nested Class Summary

static class

Cache.ArrayKey ArrayKey is a simple wrapper that provides a field-to-field equal method between encapsulated arrays.

Field Summary

private int	cachingMethod The caching method this cache uses.
static int	FULL_CACHE Constant used to specify the "full cache" mode.
private java.util.Map<java.lang.Object,java.lang.Object>	innerCache the inner map that stores associations.
static int	NO_CACHE Constant used to specify the "no cache" mode.
static int	SOFT_CACHE Constant used to specify the "soft cache" mode.

Constructor Summary

Cache(int cachingMethod)
Cache constructor.

Method Summary

void	clear() Clear the cache.
java.lang.Object	get(java.lang.Object key) Try to get an instance from the cache.
void	invalidate(java.lang.Object key) invalidates an entry (used after an insert or an update)
void	put(java.lang.Object key, java.lang.Object value) Put an instance in the cache.
int	size() Getter for the size of the cache.

Methods inherited from class java.lang.Object

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

Field Detail

NO_CACHE

public static final int NO_CACHE

Constant used to specify the "no cache" mode.

See Also:

Constant Field Values

SOFT_CACHE

public static final int SOFT_CACHE

Constant used to specify the "soft cache" mode.

See Also:

Constant Field Values

FULL_CACHE

public static final int FULL_CACHE

Constant used to specify the "full cache" mode.

See Also:

Constant Field Values

cachingMethod

private int cachingMethod

The caching method this cache uses.

innerCache

private java.util.Map<java.lang.Object,java.lang.Object> innerCache

the inner map that stores associations.

Constructor Detail

Cache

public Cache(int cachingMethod)

Cache constructor.

Parameters:

cachingMethod - required caching mode

Method Detail

put

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

Put an instance in the cache.

Parameters:

key - key field(s) of this instance

value - instance

size

public int size()

Getter for the size of the cache.

Returns:

the size of the cache

get

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

Try to get an instance from the cache.

Parameters:

key - key field(s) of the asked instance

Returns:

Asked instance or null if not found

clear

public void clear()

Clear the cache.

invalidate

public void invalidate(java.lang.Object key)

invalidates an entry (used after an insert or an update)