org.apache.commons.pool
Class BaseObjectPool<T>

java.lang.Object
  org.apache.commons.pool.BaseObjectPool<T>

Type Parameters:

T - the type of objects held in this pool

All Implemented Interfaces:

ObjectPool<T>

Direct Known Subclasses:

GenericObjectPool, SoftReferenceObjectPool, StackObjectPool

public abstract class BaseObjectPool<T>
extends Object
implements ObjectPool<T>

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: 1222396 $ $Date: 2011-12-22 14:02:25 -0500 (Thu, 22 Dec 2011) $

Author:

Rodney Waldhoff, Sandy McArthur

Constructor Summary

BaseObjectPool()

Method Summary

void	addObject() Not supported in this base implementation.
abstract T	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(T obj) Invalidates an object from the pool.
boolean	isClosed() Has this pool instance been closed.
abstract void	returnObject(T 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<T>

Throws:

UnsupportedOperationException

Exception - when PoolableObjectFactory.makeObject() fails.

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

borrowObject

public abstract T borrowObject()
                        throws Exception

Obtains an instance from the pool.

Specified by:

borrowObject in interface ObjectPool<T>

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<T>

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<T>

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<T>

Returns:

a negative value.

Throws:

UnsupportedOperationException

getNumIdle

public int getNumIdle()
               throws UnsupportedOperationException

Not supported in this base implementation.

Specified by:

getNumIdle in interface ObjectPool<T>

Returns:

a negative value.

Throws:

UnsupportedOperationException

invalidateObject

public abstract void invalidateObject(T 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<T>

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(T obj)
                           throws Exception

Returns an instance to the pool.

Specified by:

returnObject in interface ObjectPool<T>

Parameters:

obj - instance to return to the pool

Throws:

Exception