org.apache.commons.pool
Class BaseKeyedObjectPool

java.lang.Object
  extended by org.apache.commons.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: 1085933 $ $Date: 2011-03-27 06:40:20 -0700 (Sun, 27 Mar 2011) $
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.
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:
UnsupportedOperationException
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()


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