org.datanucleus.store.rdbms.datasource.dbcp.pool

Class BaseKeyedObjectPool

java.lang.Object

org.datanucleus.store.rdbms.datasource.dbcp.pool.BaseKeyedObjectPool

All Implemented Interfaces:

KeyedObjectPool

Direct Known Subclasses:

GenericKeyedObjectPool, StackKeyedObjectPool

public abstract class BaseKeyedObjectPool
extends Object
implements KeyedObjectPool

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

Since:

Pool 1.0

Version:

$Revision: 965334 $ $Date: 2010-07-18 20:19:55 -0400 (Sun, 18 Jul 2010) $

Author:

Rodney Waldhoff, Sandy McArthur

Constructor Summary

Constructors

Constructor and Description
BaseKeyedObjectPool()

Method Summary

Methods

Modifier and Type	Method and Description
void	addObject(Object key) Not supported in this base implementation.
protected void	assertOpen() Throws an IllegalStateException when this pool has been closed.
abstract Object	borrowObject(Object key) Obtains an instance from this pool for the specified key.
void	clear() Not supported in this base implementation.
void	clear(Object key) Not supported in this base implementation.
void	close() Close this pool.
int	getNumActive() Not supported in this base implementation.
int	getNumActive(Object key) Not supported in this base implementation.
int	getNumIdle() Not supported in this base implementation.
int	getNumIdle(Object key) Not supported in this base implementation.
abstract void	invalidateObject(Object key, Object obj) Invalidates an object from the pool.
protected boolean	isClosed() Has this pool instance been closed.
abstract void	returnObject(Object key, Object obj) Return an instance to the pool.
void	setFactory(KeyedPoolableObjectFactory factory) Deprecated. to be removed in pool 2.0

Methods inherited from class java.lang.Object

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

Constructor Detail

BaseKeyedObjectPool

public BaseKeyedObjectPool()

Method Detail

borrowObject

public abstract Object borrowObject(Object key)
                             throws Exception

Obtains an instance from this pool for the specified key.

Instances returned from this method will have been either newly created with makeObject or will be a previously idle object and have been activated with activateObject and then validated with validateObject.

By contract, clients must return the borrowed object using returnObject, invalidateObject, or a related method as defined in an implementation or sub-interface, using a key that is equivalent to the one used to borrow the instance in the first place.

The behaviour of this method when the pool has been exhausted is not strictly specified (although it may be specified by implementations). Older versions of this method would return null to indicate exhaustion, newer versions are encouraged to throw a NoSuchElementException.

Specified by:

borrowObject in interface KeyedObjectPool

Parameters:

key - the key used to obtain the object

Returns:

an instance from this pool.

Throws:

IllegalStateException - after close has been called on this pool

Exception - when makeObject throws an exception

NoSuchElementException - when the pool is exhausted and cannot or will not return another instance

returnObject

public abstract void returnObject(Object key,
                Object obj)
                           throws Exception

Return an instance to the pool. By contract, obj must have been obtained using borrowObject or a related method as defined in an implementation or sub-interface using a key that is equivalent to the one used to borrow the instance in the first place.

Specified by:

returnObject in interface KeyedObjectPool

Parameters:

key - the key used to obtain the object

obj - a borrowed instance to be returned.

Throws:

Exception

invalidateObject

public abstract void invalidateObject(Object key,
                    Object obj)
                               throws Exception

Invalidates an object from the pool.

By contract, obj must have been obtained using borrowObject using a key that is equivalent to the one used to borrow the Object in the first place.

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 KeyedObjectPool

Parameters:

key - the key used to obtain the object

obj - a borrowed instance to be returned.

Throws:

Exception

addObject

public void addObject(Object key)
               throws Exception,
                      UnsupportedOperationException

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

Specified by:

addObject in interface KeyedObjectPool

Parameters:

key - ignored

Throws:

UnsupportedOperationException

Exception - when KeyedPoolableObjectFactory.makeObject(java.lang.Object) fails.

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

getNumIdle

public int getNumIdle(Object key)
               throws UnsupportedOperationException

Not supported in this base implementation.

Specified by:

getNumIdle in interface KeyedObjectPool

Parameters:

key - ignored

Returns:

a negative value.

Throws:

UnsupportedOperationException - deprecated: when this implementation doesn't support the operation

getNumActive

public int getNumActive(Object key)
                 throws UnsupportedOperationException

Not supported in this base implementation.

Specified by:

getNumActive in interface KeyedObjectPool

Parameters:

key - ignored

Returns:

a negative value.

Throws:

UnsupportedOperationException - deprecated: when this implementation doesn't support the operation

getNumIdle

public int getNumIdle()
               throws UnsupportedOperationException

Not supported in this base implementation.

Specified by:

getNumIdle in interface KeyedObjectPool

Returns:

a negative value.

Throws:

UnsupportedOperationException - deprecated: when this implementation doesn't support the operation

getNumActive

public int getNumActive()
                 throws UnsupportedOperationException

Not supported in this base implementation.

Specified by:

getNumActive in interface KeyedObjectPool

Returns:

a negative value.

Throws:

UnsupportedOperationException - deprecated: when this implementation doesn't support the operation

clear

public void clear()
           throws Exception,
                  UnsupportedOperationException

Not supported in this base implementation.

Specified by:

clear in interface KeyedObjectPool

Throws:

UnsupportedOpereationException

UnsupportedOperationException - when this implementation doesn't support the operation

Exception

clear

public void clear(Object key)
           throws Exception,
                  UnsupportedOperationException

Not supported in this base implementation.

Specified by:

clear in interface KeyedObjectPool

Parameters:

key - ignored

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 KeyedObjectPool

Throws:

Exception

setFactory

public void setFactory(KeyedPoolableObjectFactory factory)
                throws IllegalStateException,
                       UnsupportedOperationException

Deprecated. to be removed in pool 2.0

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

Specified by:

setFactory in interface KeyedObjectPool

Parameters:

factory - the new KeyedPoolableObjectFactory

Throws:

IllegalStateException - when the factory cannot be set at this time

UnsupportedOperationException - when this implementation doesn't support the operation

isClosed

protected final boolean isClosed()

Has this pool instance been closed.

Returns:

true when this pool has been closed.

Since:

Pool 1.4

assertOpen

protected final void assertOpen()
                         throws IllegalStateException

Throws an IllegalStateException when this pool has been closed.

Throws:

IllegalStateException - when this pool has been closed.

Since:

Pool 1.4

See Also:

isClosed()