com.compoze.collab.util
Class SoftCache

java.lang.Object
  java.lang.Thread
      com.compoze.collab.util.SoftCache

All Implemented Interfaces

Runnable

public class SoftCache
extends Thread

A class for caching values using SoftReferences. Values in the cache that are otherwise unused can be garbage collected. A value of null will be represented by an instance of NullValue.

Nested Class Summary

static class

SoftCache.NullValue Used to represent null values in the cache.

Field Summary

Fields inherited from class java.lang.Thread

MAX_PRIORITY, MIN_PRIORITY, NORM_PRIORITY

Constructor Summary

SoftCache()
Create a SoftCache.

Method Summary

Object	get(Object key) Get the cached value, if any, for a key.
Object	put(Object key, Object value) Put a value for key in the cache.
void	run() The code for the thread that cleans garbage-collected values from the cache.

Methods inherited from class java.lang.Thread

activeCount, checkAccess, 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

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

Constructor Detail

SoftCache

public SoftCache()

Create a SoftCache.

Method Detail

get

public Object get(Object key)

Get the cached value, if any, for a key. If there is no cached value, returns null. If the cached value is null, returns an instance of SoftCache.NullValue.

Parameters

key - the key to look up

Returns

the cached value; null if no cached value; an instance of NullValue if the cached value is null

put

public Object put(Object key,
                  Object value)

Put a value for key in the cache. Returns the old value, if any.

Parameters

key - the hash key; cannot be null

value - the value for key; can be null

Returns

previous value for key; null if none or if the previous value has been cleared by the garbage collector; an instance of NullValue if the cached value is null

run

public void run()

The code for the thread that cleans garbage-collected values from the cache. Do not call this method.

Specified by:

run in interface Runnable

Overrides:

run in class Thread