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 :

• NO_CACHE (cache='none', the default, in velosurf.xml) : no caching occurs on this entity.
• SOFT_CACHE (cache='soft' in velosurf.xml) : caching occurs as long as memory is ont reclaimed (see the behaviour of java soft references).
• FULL_CACHE (cache='full' in velosuf.xml) : 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 update requests, but global updates are not taken into account.

This caching mechanism is meant for straightforward optimizations in simple situations, for instance to avoid re-fetching the loggued user at each request.

Author:

Claude Brisson

Nested Class Summary

static class

Cache.ArrayKey

Field Summary

protected int	cachingMethod The caching method this cache uses
static int	FULL_CACHE constant used to specify the "full cache" mode
protected java.util.Map	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

protected int cachingMethod

The caching method this cache uses

innerCache

protected java.util.Map 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)