org.apache.commons.pool
Class BaseObjectPool

java.lang.Object
  org.apache.commons.pool.BaseObjectPool

All Implemented Interfaces:

ObjectPool

Direct Known Subclasses:

GenericObjectPool, SoftReferenceObjectPool, StackObjectPool

public abstract class BaseObjectPool
extends Object
implements ObjectPool

A simple base implementation of ObjectPool. Optional operations are implemented to either do nothing, return a value indicating it is unsupported or throw UnsupportedOperationException.

Since:

Pool 1.0

Version:

$Revision: 1084645 $ $Date: 2011-03-23 10:11:19 -0700 (Wed, 23 Mar 2011) $

Author:

Rodney Waldhoff, Sandy McArthur

Constructor Summary

BaseObjectPool()

Method Summary

void	addObject() Not supported in this base implementation.
abstract Object	borrowObject() Obtains an instance from the pool.
void	clear() Not supported in this base implementation.
void	close() Close this pool.
int	getNumActive() Not supported in this base implementation.
int	getNumIdle() Not supported in this base implementation.
abstract void	invalidateObject(Object obj) Invalidates an object from the pool.
boolean	isClosed() Has this pool instance been closed.
abstract void	returnObject(Object obj) Returns an instance to the pool.

Methods inherited from class java.lang.Object

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

Constructor Detail

BaseObjectPool

public BaseObjectPool()

Method Detail

addObject

public void addObject()
               throws Exception,
                      UnsupportedOperationException

Not supported in this base implementation. Always throws an UnsupportedOperationException, subclasses should override this behavior.

Specified by:

addObject in interface ObjectPool

Throws:

UnsupportedOperationException

Exception - when PoolableObjectFactory.makeObject() fails.

IllegalStateException - after ObjectPool.close() has been called on this pool.

borrowObject

public abstract Object borrowObject()
                             throws Exception

Obtains an instance from the pool.

Specified by:

borrowObject in interface ObjectPool

Returns:

an instance from the pool

Throws:

Exception - if an instance cannot be obtained from the pool

clear

public void clear()
           throws Exception,
                  UnsupportedOperationException

Not supported in this base implementation.

Specified by:

clear in interface ObjectPool

Throws:

UnsupportedOperationException

Exception

close

public void close()
           throws Exception

Close this pool. This affects the behavior of isClosed and assertOpen.

Specified by:

close in interface ObjectPool

Throws:

Exception - deprecated: implementations should silently fail if not all resources can be freed.

getNumActive

public int getNumActive()
                 throws UnsupportedOperationException

Not supported in this base implementation.

Specified by:

getNumActive in interface ObjectPool

Returns:

a negative value.

Throws:

UnsupportedOperationException

getNumIdle

public int getNumIdle()
               throws UnsupportedOperationException

Not supported in this base implementation.

Specified by:

getNumIdle in interface ObjectPool

Returns:

a negative value.

Throws:

UnsupportedOperationException

invalidateObject

public abstract void invalidateObject(Object obj)
                               throws Exception

Invalidates an object from the pool.

By contract, obj must have been obtained using borrowObject.

This method should be used when an object that has been borrowed is determined (due to an exception or other problem) to be invalid.

Specified by:

invalidateObject in interface ObjectPool

Parameters:

obj - a borrowed instance to be disposed.

Throws:

Exception

isClosed

public final boolean isClosed()

Has this pool instance been closed.

Returns:

true when this pool has been closed.

returnObject

public abstract void returnObject(Object obj)
                           throws Exception

Returns an instance to the pool.

Specified by:

returnObject in interface ObjectPool

Parameters:

obj - instance to return to the pool

Throws:

Exception