org.ws4d.java.util

Class FairObjectPool

java.lang.Object

org.ws4d.java.util.TimedEntry

org.ws4d.java.util.FairObjectPool

All Implemented Interfaces:

java.lang.Runnable

public class FairObjectPool
extends TimedEntry
implements java.lang.Runnable

This object pool supports a maximum size in addition to the behavior the normal object pool has. When a maxSize is set, the acquire call may block until another thread returns its object to the pool. When no max size is set the object pool will behave as if it is a normal object pool.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	FairObjectPool.InstanceCreator

Constructor Summary

Constructors

Constructor and Description
FairObjectPool(FairObjectPool.InstanceCreator creator) Creates a new pool with no limit on the maximum number of pooled objects and an initial pool size of 10.
FairObjectPool(FairObjectPool.InstanceCreator creator, int initialSize) Creates a new pool with no limit on the maximum number of pooled objects and the specified initial pool size.
FairObjectPool(FairObjectPool.InstanceCreator creator, int initialSize, int maxSize) Creates a new pool with a maximum total number of pooled objects of maxSize.

Method Summary

Modifier and Type	Method and Description
java.lang.Object	acquire() Gives out an instance produced by the InstanceCreator.
java.lang.Object	acuireInternal()
void	dispose()
void	release(java.lang.Object o) returns the object to the pool.
void	run()
protected void	timedOut() Runs what should be done at time out.

Methods inherited from class org.ws4d.java.util.TimedEntry

isDisabled, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

FairObjectPool

public FairObjectPool(FairObjectPool.InstanceCreator creator)

Creates a new pool with no limit on the maximum number of pooled objects and an initial pool size of 10.

Parameters:

creator - the instance creator for creating new pooled objects

FairObjectPool

public FairObjectPool(FairObjectPool.InstanceCreator creator,
                      int initialSize)

Creates a new pool with no limit on the maximum number of pooled objects and the specified initial pool size.

Parameters:

creator - the instance creator for creating new pooled objects

FairObjectPool

public FairObjectPool(FairObjectPool.InstanceCreator creator,
                      int initialSize,
                      int maxSize)

Creates a new pool with a maximum total number of pooled objects of maxSize. The pool will initially have a capacity of initialSize instances. New instances will be created by the specified creator.

Parameters:

creator - the instance creator for creating new pooled objects

initialSize - the initial pool size

maxSize - the maximum pool size; if -1, no limit on the pool size is imposed

Method Detail

acquire

public java.lang.Object acquire()

Gives out an instance produced by the InstanceCreator. If a max size is set, this method will block if the maximum number of object has been acquired. It will return with a new acquired object. The order in witch two calls of acquire from two separate threads will return is FIFO. Specifically the first thing that happens as soon as this method is invoked is to save the System.currentTimeMillis(). This value is used to ensure FIFO order.

Returns:

an Object created by the InstanceCreator.

acuireInternal

public java.lang.Object acuireInternal()

release

public void release(java.lang.Object o)

returns the object to the pool.

timedOut

protected void timedOut()

Description copied from class: TimedEntry

Runs what should be done at time out. Will be called by the Watchdog at time out.

Specified by:

timedOut in class TimedEntry

dispose

public void dispose()

run

public void run()

Specified by:

run in interface java.lang.Runnable