lazyj.cache

Class Cache

java.lang.Object

java.lang.Thread

lazyj.cache.Cache

All Implemented Interfaces:

java.lang.Runnable

public class Cache
extends java.lang.Thread

This class is a central point where all the data caching structure can be stored, for universal access. Any structure registered here will be automatically refreshed and it will be visible to everybody provided they know the registration key.

To register something into this repository you need to have:

• an unique name for the stored structure
• a class that implements CacheElement

Since:

2006-10-03

Author:

costing

Nested Class Summary

Nested classes/interfaces inherited from class java.lang.Thread

java.lang.Thread.State, java.lang.Thread.UncaughtExceptionHandler

Field Summary

Fields inherited from class java.lang.Thread

MAX_PRIORITY, MIN_PRIORITY, NORM_PRIORITY

Method Summary

Methods

Modifier and Type	Method and Description
static CacheElement<?,?>	get(java.lang.String sKey) Use this method to retrieve an entry you are interested in.
static java.util.Set<java.lang.String>	getKeySet() Method to discover all the registered entries.
static void	refresh(java.lang.String sKey) Force a refresh of a cache entry.
static void	register(java.lang.String sKey, CacheElement<?,?> ce) Register an element into the Cache.
void	run() This thread will take each entry that expires and refreshes it.

Methods inherited from class java.lang.Thread

activeCount, checkAccess, clone, countStackFrames, currentThread, destroy, dumpStack, enumerate, getAllStackTraces, getContextClassLoader, getDefaultUncaughtExceptionHandler, getId, getName, getPriority, getStackTrace, getState, getThreadGroup, getUncaughtExceptionHandler, holdsLock, interrupt, interrupted, isAlive, isDaemon, isInterrupted, join, join, join, resume, setContextClassLoader, setDaemon, setDefaultUncaughtExceptionHandler, setName, setPriority, setUncaughtExceptionHandler, sleep, sleep, start, stop, stop, suspend, toString, yield

Methods inherited from class java.lang.Object

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

Method Detail

register

public static final void register(java.lang.String sKey,
            CacheElement<?,?> ce)

Register an element into the Cache. Make sure that the key you give here is unique between all applications! The last added entry for a given name is the one that will be seen by everybody.

The method CacheElement.refresh() will be called before the actual registration, so you don't have to initialize the entry yourself. A construction like:

 static{
           Cache.register("unique key", new CacheElementImplementation());
 }

is probably the best way of using the Cache.

The same method can be used to remove a cache entry. Just give null for the ce parameter.

Parameters:

sKey - unique key

ce - cached structure

get

public static final CacheElement<?,?> get(java.lang.String sKey)

Use this method to retrieve an entry you are interested in. It will return the last registered CacheElement for that key, or null if there is no such entry. Typical use is something like:

     CacheElement ce = Cache.get("unique key");
     if (ce!=null){
         SomeObject so = (SomeObject) ce.get("internal name");
     } 
 

Parameters:

sKey - the unique key given at registration

Returns:

the CacheElement that was last registered for this key

refresh

public static final void refresh(java.lang.String sKey)

Force a refresh of a cache entry. Use this if you know that some value has changed and you need to make sure that the information in the cache is updated.

You should not call the refresh() method on the CacheElement directly because the Cache will not be aware of the call and will try to update itself the entry after an incorrect period of time. Not a big deal though :)

Parameters:

sKey - the unique key to refresh

getKeySet

public static final java.util.Set<java.lang.String> getKeySet()

Method to discover all the registered entries. It will return the set of all keys that were registered into the Cache.

Returns:

the Set of registered keys

run

public void run()

This thread will take each entry that expires and refreshes it.

Specified by:

run in interface java.lang.Runnable

Overrides:

run in class java.lang.Thread