BaseKeyedObjectPool (Commons Pool 1.5.1 API)

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org.apache.commons.pool
Class BaseKeyedObjectPool

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

All Implemented Interfaces:: KeyedObjectPool

Direct Known Subclasses:: GenericKeyedObjectPool, StackKeyedObjectPool

public abstract class BaseKeyedObjectPool
extends Object
implements KeyedObjectPool
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: 777748 $ $Date: 2009-05-22 20:00:44 -0400 (Fri, 22 May 2009) $
Author:: Rodney Waldhoff, Sandy McArthur

Constructor Summary
`BaseKeyedObjectPool()`

Method Summary
`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 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 `Object` in the first place.
`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)` Not supported in this base implementation.

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

Description copied from interface: KeyedObjectPool

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

Description copied from interface: KeyedObjectPool

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

Description copied from interface: KeyedObjectPool

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 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 - the key a new instance should be added to
Throws:: Exception - when KeyedPoolableObjectFactory.makeObject(java.lang.Object) fails.; IllegalStateException - after KeyedObjectPool.close() has been called on this pool.; UnsupportedOperationException - when this pool cannot add new idle objects.