org.apache.commons.pool.impl
Class StackObjectPool

java.lang.Object
  extended by org.apache.commons.pool.BaseObjectPool
      extended by org.apache.commons.pool.impl.StackObjectPool
All Implemented Interfaces:
ObjectPool

public class StackObjectPool
extends BaseObjectPool
implements ObjectPool

A simple, Stack-based ObjectPool implementation.

Given a PoolableObjectFactory, this class will maintain a simple pool of instances. A finite number of "sleeping" or idle instances is enforced, but when the pool is empty, new instances are created to support the new load. Hence this class places no limit on the number of "active" instances created by the pool, but is quite useful for re-using Objects without introducing artificial limits.

Version:
$Revision: 383290 $ $Date: 2006-03-05 02:00:15 -0500 (Sun, 05 Mar 2006) $
Author:
Rodney Waldhoff, Dirk Verbeeck

Constructor Summary
StackObjectPool()
          Create a new pool using no factory.
StackObjectPool(int maxIdle)
          Create a new pool using no factory.
StackObjectPool(int maxIdle, int initIdleCapacity)
          Create a new pool using no factory.
StackObjectPool(PoolableObjectFactory factory)
          Create a new StackObjectPool using the specified factory to create new instances.
StackObjectPool(PoolableObjectFactory factory, int maxIdle)
          Create a new SimpleObjectPool using the specified factory to create new instances, capping the number of "sleeping" instances to max.
StackObjectPool(PoolableObjectFactory factory, int maxIdle, int initIdleCapacity)
          Create a new SimpleObjectPool using the specified factory to create new instances, capping the number of "sleeping" instances to max, and initially allocating a container capable of containing at least init instances.
 
Method Summary
 void addObject()
          Create an object, and place it into the pool.
 java.lang.Object borrowObject()
          Obtain an instance from my pool.
 void clear()
          Not supported in this base implementation.
 void close()
          Close this pool, and free any resources associated with it.
 int getNumActive()
          Not supported in this base implementation.
 int getNumIdle()
          Not supported in this base implementation.
 void invalidateObject(java.lang.Object obj)
          Invalidates an object from the pool By contract, obj MUST have been obtained using borrowObject or a related method as defined in an implementation or sub-interface.
 void returnObject(java.lang.Object obj)
          Return an instance to my pool.
 void setFactory(PoolableObjectFactory factory)
          Not supported in this base implementation.
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

StackObjectPool

public StackObjectPool()
Create a new pool using no factory. Clients must first populate the pool using returnObject(java.lang.Object) before they can be borrowed.


StackObjectPool

public StackObjectPool(int maxIdle)
Create a new pool using no factory. Clients must first populate the pool using returnObject(java.lang.Object) before they can be borrowed.

Parameters:
maxIdle - cap on the number of "sleeping" instances in the pool

StackObjectPool

public StackObjectPool(int maxIdle,
                       int initIdleCapacity)
Create a new pool using no factory. Clients must first populate the pool using returnObject(java.lang.Object) before they can be borrowed.

Parameters:
maxIdle - cap on the number of "sleeping" instances in the pool
initIdleCapacity - initial size of the pool (this specifies the size of the container, it does not cause the pool to be pre-populated.)

StackObjectPool

public StackObjectPool(PoolableObjectFactory factory)
Create a new StackObjectPool using the specified factory to create new instances.

Parameters:
factory - the PoolableObjectFactory used to populate the pool

StackObjectPool

public StackObjectPool(PoolableObjectFactory factory,
                       int maxIdle)
Create a new SimpleObjectPool using the specified factory to create new instances, capping the number of "sleeping" instances to max.

Parameters:
factory - the PoolableObjectFactory used to populate the pool
maxIdle - cap on the number of "sleeping" instances in the pool

StackObjectPool

public StackObjectPool(PoolableObjectFactory factory,
                       int maxIdle,
                       int initIdleCapacity)
Create a new SimpleObjectPool using the specified factory to create new instances, capping the number of "sleeping" instances to max, and initially allocating a container capable of containing at least init instances.

Parameters:
factory - the PoolableObjectFactory used to populate the pool
maxIdle - cap on the number of "sleeping" instances in the pool
initIdleCapacity - initial size of the pool (this specifies the size of the container, it does not cause the pool to be pre-populated.)
Method Detail

addObject

public void addObject()
               throws java.lang.Exception
Create an object, and place it into the pool. addObject() is useful for "pre-loading" a pool with idle objects.

Specified by:
addObject in interface ObjectPool
Overrides:
addObject in class BaseObjectPool
Throws:
java.lang.Exception - when the _factory has a problem creating an object.

borrowObject

public java.lang.Object borrowObject()
                              throws java.lang.Exception
Description copied from interface: ObjectPool
Obtain an instance from my pool. By contract, clients MUST return the borrowed instance using returnObject or a related method as defined in an implementation or sub-interface.

The behaviour of this method when the pool has been exhausted is not specified (although it may be specified by implementations).

Specified by:
borrowObject in interface ObjectPool
Specified by:
borrowObject in class BaseObjectPool
Returns:
an instance from my pool.
Throws:
java.lang.Exception

clear

public void clear()
Description copied from class: BaseObjectPool
Not supported in this base implementation.

Specified by:
clear in interface ObjectPool
Overrides:
clear in class BaseObjectPool

close

public void close()
           throws java.lang.Exception
Description copied from interface: ObjectPool
Close this pool, and free any resources associated with it.

Specified by:
close in interface ObjectPool
Overrides:
close in class BaseObjectPool
Throws:
java.lang.Exception

getNumActive

public int getNumActive()
Description copied from class: BaseObjectPool
Not supported in this base implementation.

Specified by:
getNumActive in interface ObjectPool
Overrides:
getNumActive in class BaseObjectPool
Returns:
the number of instances currently borrowed in my pool

getNumIdle

public int getNumIdle()
Description copied from class: BaseObjectPool
Not supported in this base implementation.

Specified by:
getNumIdle in interface ObjectPool
Overrides:
getNumIdle in class BaseObjectPool
Returns:
the number of instances currently idle in my pool

invalidateObject

public void invalidateObject(java.lang.Object obj)
                      throws java.lang.Exception
Description copied from interface: ObjectPool
Invalidates an object from the pool By contract, obj MUST have been obtained using borrowObject or a related method as defined in an implementation or sub-interface.

This method should be used when an object that has been borrowed is determined (due to an exception or other problem) to be invalid. If the connection should be validated before or after borrowing, then the PoolableObjectFactory.validateObject(java.lang.Object) method should be used instead.

Specified by:
invalidateObject in interface ObjectPool
Specified by:
invalidateObject in class BaseObjectPool
Parameters:
obj - a borrowed instance to be returned.
Throws:
java.lang.Exception

returnObject

public void returnObject(java.lang.Object obj)
                  throws java.lang.Exception
Description copied from interface: ObjectPool
Return an instance to my pool. By contract, obj MUST have been obtained using borrowObject or a related method as defined in an implementation or sub-interface.

Specified by:
returnObject in interface ObjectPool
Specified by:
returnObject in class BaseObjectPool
Parameters:
obj - a borrowed instance to be returned.
Throws:
java.lang.Exception

setFactory

public void setFactory(PoolableObjectFactory factory)
                throws java.lang.IllegalStateException
Description copied from class: BaseObjectPool
Not supported in this base implementation.

Specified by:
setFactory in interface ObjectPool
Overrides:
setFactory in class BaseObjectPool
Parameters:
factory - the PoolableObjectFactory I use to create new instances.
Throws:
java.lang.IllegalStateException - when the factory cannot be set at this time


Copyright © 2001-2003 Apache Software Foundation. Documenation generated April 15 2009.