JBoss API: Class AbstractInstancePool

org.jboss.ejb.plugins
Class AbstractInstancePool

java.lang.Object
  |
  +--org.jboss.ejb.plugins.AbstractInstancePool

All Implemented Interfaces:

ContainerPlugin, InstancePool, Service, XmlLoadable

Direct Known Subclasses:

EntityInstancePool, MessageDrivenInstancePool, StatefulSessionInstancePool, StatelessSessionInstancePool

public abstract class AbstractInstancePool

extends java.lang.Object

implements InstancePool, XmlLoadable

Abstract Instance Pool class containing the basic logic to create an EJB Instance Pool.

Version:

$Revision: 1.9.6.9 $

Revisions:

20010704 marcf:

• - Pools if used, do not reuse but restock the pile with fresh instances

20010920 Sacha Labourey:

• - Pooling made optional and only activated in concrete subclasses for SLSB and MDB

20011208 Vincent Harcq:

• - Added InstancePoolFeeder concept for initializing the pool.

Author:

Rickard Öberg, Marc Fleury, Andreas Schaefer, Sacha Labourey, Scott Stark/a>

See Also:

Field Summary

protected Container	container The Container the instance pool is associated with
protected Logger	log The logging interface
protected int	maxSize The maximum number of instances allowed in the pool
protected java.util.Stack	pool The instance pool stack
protected InstancePoolFeeder	poolFeeder The pool seed task set from the feeder-policy config element
protected boolean	reclaim determine if we reuse EnterpriseContext objects i.e.

Constructor Summary

AbstractInstancePool()

Method Summary

void	add() Add a instance in the pool by invoking create() with a new bean instance.
protected abstract EnterpriseContext	create(java.lang.Object instance)
void	destroy()
void	discard(EnterpriseContext ctx) Discard an anonymous instance after invocation.
void	free(EnterpriseContext ctx) Return an instance after invocation.
EnterpriseContext	get() Get an instance without identity.
Container	getContainer()
int	getCurrentSize() Return the size of the pool.
int	getMaxSize() Get the maximum size of the pool.
boolean	getReclaim() A pool is reclaim if it push back its dirty instances in its stack.
void	importXml(org.w3c.dom.Element element) XmlLoadable implementation
void	init()
void	setContainer(Container c) Set the callback to the container.
void	setReclaim(boolean reclaim)
void	start()
void	stop()

Methods inherited from class java.lang.Object

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

Field Detail

log

protected Logger log

The logging interface

container

protected Container container

The Container the instance pool is associated with

pool

protected java.util.Stack pool

The instance pool stack

maxSize

protected int maxSize

The maximum number of instances allowed in the pool

reclaim

protected boolean reclaim

determine if we reuse EnterpriseContext objects i.e. if we actually do pooling

poolFeeder

protected InstancePoolFeeder poolFeeder

The pool seed task set from the feeder-policy config element

Constructor Detail

AbstractInstancePool

public AbstractInstancePool()

Method Detail

setContainer

public void setContainer(Container c)

Set the callback to the container. This is for initialization. The IM may extract the configuration from the container.

Specified by:

setContainer in interface ContainerPlugin

Parameters:

c -

getContainer

public Container getContainer()

Returns:

Callback to the container which can be null if not set proviously

init

public void init()
          throws java.lang.Exception

Specified by:

init in interface Service

start

public void start()
           throws java.lang.Exception

Specified by:

start in interface Service

stop

public void stop()

Specified by:

stop in interface Service

destroy

public void destroy()

Specified by:

destroy in interface Service

getReclaim

public boolean getReclaim()

A pool is reclaim if it push back its dirty instances in its stack.

setReclaim

public void setReclaim(boolean reclaim)

add

public void add()
         throws java.lang.Exception

Add a instance in the pool by invoking create() with a new bean instance.

Specified by:

add in interface InstancePool

Throws:

Exception, - thrown on ctx creation failure

get

public EnterpriseContext get()
                      throws java.lang.Exception

Get an instance without identity. Can be used by finders,create-methods, and activation. This method cannot be synchronized since it may block on the strictMaxSize semaphore.

Specified by:

get in interface InstancePool

Returns:

Context with instance

Throws:

java.rmi.RemoteException -

free

public void free(EnterpriseContext ctx)

Return an instance after invocation. Called in 2 cases: a) Done with finder method b) Just removed

Specified by:

free in interface InstancePool

Parameters:

ctx -

discard

public void discard(EnterpriseContext ctx)

Description copied from interface: InstancePool

Discard an anonymous instance after invocation. This is called if the instance should not be reused, perhaps due to some exception being thrown from it.

Specified by:

discard in interface InstancePool

Following copied from interface: org.jboss.ejb.InstancePool

Parameters:

ctx -

getCurrentSize

public int getCurrentSize()

Description copied from interface: InstancePool

Return the size of the pool.

Specified by:

getCurrentSize in interface InstancePool

Following copied from interface: org.jboss.ejb.InstancePool

Returns:

the size of the pool.

getMaxSize

public int getMaxSize()

Description copied from interface: InstancePool

Get the maximum size of the pool.

Specified by:

getMaxSize in interface InstancePool

Following copied from interface: org.jboss.ejb.InstancePool

Returns:

the size of the pool.

importXml

public void importXml(org.w3c.dom.Element element)
               throws DeploymentException

XmlLoadable implementation

Specified by:

importXml in interface XmlLoadable

create

protected abstract EnterpriseContext create(java.lang.Object instance)
                                     throws java.lang.Exception