org.apache.commons.pool.impl

Class StackKeyedObjectPool

Implemented Interfaces:
KeyedObjectPool

public class StackKeyedObjectPool
extends BaseKeyedObjectPool
implements KeyedObjectPool

A simple, Stack-based KeyedObjectPool implementation.

Given a KeyedPoolableObjectFactory, this class will maintain a simple pool of instances. A finite number of "sleeping" or inactive instances is enforced, but when the pool is empty, new instances are created to support the new load. Hence this class places no limit on the number of "active" instances created by the pool, but is quite useful for re-using Objects without introducing artificial limits.

Version:
$Revision: 1.14 $ $Date: 2004/02/28 12:16:21 $
Author:
Rodney Waldhoff

Constructor Summary

StackKeyedObjectPool()
Create a new pool using no factory.
StackKeyedObjectPool(int max)
Create a new pool using no factory.
StackKeyedObjectPool(int max, int init)
Create a new pool using no factory.
StackKeyedObjectPool(KeyedPoolableObjectFactory factory)
Create a new SimpleKeyedObjectPool using the specified factory to create new instances.
StackKeyedObjectPool(KeyedPoolableObjectFactory factory, int max)
Create a new SimpleKeyedObjectPool using the specified factory to create new instances.
StackKeyedObjectPool(KeyedPoolableObjectFactory factory, int max, int init)
Create a new SimpleKeyedObjectPool using the specified factory to create new instances.

Method Summary

void
addObject(Object key)
Create an object using my factory or other implementation dependent mechanism, and place it into the pool.
Object
borrowObject(Object key)
Obtain an instance from my pool for the specified key.
void
clear()
Clears my pool, removing all pooled instances (optional operation).
void
clear(Object key)
Clears the specified pool, removing all pooled instances corresponding to the given key (optional operation).
void
close()
Close this pool, and free any resources associated with it.
int
getNumActive()
Returns the total number of instances current borrowed from my pool but not yet returned (optional operation).
int
getNumActive(Object key)
Returns the number of instances currently borrowed from but not yet returned to my pool corresponding to the given key (optional operation).
int
getNumIdle()
Returns the total number of instances currently idle in my pool (optional operation).
int
getNumIdle(Object key)
Returns the number of instances corresponding to the given key currently idle in my pool (optional operation).
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.
void
returnObject(Object key, Object obj)
Return an instance to my pool.
void
setFactory(KeyedPoolableObjectFactory factory)
Sets the factory I use to create new instances (optional operation).
String
toString()

Methods inherited from class org.apache.commons.pool.BaseKeyedObjectPool

addObject, borrowObject, clear, clear, close, getNumActive, getNumActive, getNumIdle, getNumIdle, invalidateObject, returnObject, setFactory

Constructor Details

StackKeyedObjectPool

public StackKeyedObjectPool()
Create a new pool using no factory. Clients must first populate the pool using returnObject(java.lang.Object,java.lang.Object) before they can be borrowed.

StackKeyedObjectPool

public StackKeyedObjectPool(int max)
Create a new pool using no factory. Clients must first populate the pool using returnObject(java.lang.Object,java.lang.Object) before they can be borrowed.
Parameters:
max - cap on the number of "sleeping" instances in the pool

StackKeyedObjectPool

public StackKeyedObjectPool(int max,
                            int init)
Create a new pool using no factory. Clients must first populate the pool using returnObject(java.lang.Object,java.lang.Object) before they can be borrowed.
Parameters:
max - cap on the number of "sleeping" instances in the pool
init - initial size of the pool (this specifies the size of the container, it does not cause the pool to be pre-populated.)

StackKeyedObjectPool

public StackKeyedObjectPool(KeyedPoolableObjectFactory factory)
Create a new SimpleKeyedObjectPool using the specified factory to create new instances.
Parameters:
factory - the KeyedPoolableObjectFactory used to populate the pool

StackKeyedObjectPool

public StackKeyedObjectPool(KeyedPoolableObjectFactory factory,
                            int max)
Create a new SimpleKeyedObjectPool using the specified factory to create new instances. capping the number of "sleeping" instances to max
Parameters:
factory - the KeyedPoolableObjectFactory used to populate the pool
max - cap on the number of "sleeping" instances in the pool

StackKeyedObjectPool

public StackKeyedObjectPool(KeyedPoolableObjectFactory factory,
                            int max,
                            int init)
Create a new SimpleKeyedObjectPool using the specified factory to create new instances. capping the number of "sleeping" instances to max, and initially allocating a container capable of containing at least init instances.
Parameters:
factory - the KeyedPoolableObjectFactory used to populate the pool
max - cap on the number of "sleeping" instances in the pool
init - initial size of the pool (this specifies the size of the container, it does not cause the pool to be pre-populated.)

Method Details

addObject

public void addObject(Object key)
            throws Exception
Create an object using my factory or other implementation dependent mechanism, and place it into the pool. addObject() is useful for "pre-loading" a pool with idle objects. (Optional operation).
Specified by:
addObject in interface KeyedObjectPool
Overrides:
addObject in interface BaseKeyedObjectPool

borrowObject

public Object borrowObject(Object key)
            throws Exception
Obtain an instance from my pool for the specified key. By contract, clients MUST return the borrowed object using returnObject, 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:
borrowObject in interface KeyedObjectPool
Overrides:
borrowObject in interface BaseKeyedObjectPool
Parameters:
key - the key used to obtain the object
Returns:
an instance from my pool.

clear

public void clear()
Clears my pool, removing all pooled instances (optional operation). Throws UnsupportedOperationException if the pool cannot be cleared.
Specified by:
clear in interface KeyedObjectPool
Overrides:
clear in interface BaseKeyedObjectPool

clear

public void clear(Object key)
Clears the specified pool, removing all pooled instances corresponding to the given key (optional operation). Throws UnsupportedOperationException if the pool cannot be cleared.
Specified by:
clear in interface KeyedObjectPool
Overrides:
clear in interface BaseKeyedObjectPool
Parameters:
key - the key to clear

close

public void close()
            throws Exception
Close this pool, and free any resources associated with it.
Specified by:
close in interface KeyedObjectPool
Overrides:
close in interface BaseKeyedObjectPool

getNumActive

public int getNumActive()
Returns the total number of instances current borrowed from my pool but not yet returned (optional operation). Throws UnsupportedOperationException if this information is not available.
Specified by:
getNumActive in interface KeyedObjectPool
Overrides:
getNumActive in interface BaseKeyedObjectPool
Returns:
the total number of instances currently borrowed from my pool

getNumActive

public int getNumActive(Object key)
Returns the number of instances currently borrowed from but not yet returned to my pool corresponding to the given key (optional operation). Throws UnsupportedOperationException if this information is not available.
Specified by:
getNumActive in interface KeyedObjectPool
Overrides:
getNumActive in interface BaseKeyedObjectPool
Parameters:
key - the key
Returns:
the number of instances corresponding to the given key currently borrowed in my pool

getNumIdle

public int getNumIdle()
Returns the total number of instances currently idle in my pool (optional operation). Throws UnsupportedOperationException if this information is not available.
Specified by:
getNumIdle in interface KeyedObjectPool
Overrides:
getNumIdle in interface BaseKeyedObjectPool
Returns:
the total number of instances currently idle in my pool

getNumIdle

public int getNumIdle(Object key)
Returns the number of instances corresponding to the given key currently idle in my pool (optional operation). Throws UnsupportedOperationException if this information is not available.
Specified by:
getNumIdle in interface KeyedObjectPool
Overrides:
getNumIdle in interface BaseKeyedObjectPool
Parameters:
key - the key
Returns:
the number of instances corresponding to the given key currently idle in my pool

invalidateObject

public void invalidateObject(Object key,
                             Object obj)
            throws Exception
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. If the connection should be validated before or after borrowing, then the PoolableObjectFactory.validateObject(Object) method should be used instead.

Specified by:
invalidateObject in interface KeyedObjectPool
Overrides:
invalidateObject in interface BaseKeyedObjectPool
Parameters:
obj - a borrowed instance to be returned.

returnObject

public void returnObject(Object key,
                         Object obj)
            throws Exception
Return an instance to my 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.
Specified by:
returnObject in interface KeyedObjectPool
Overrides:
returnObject in interface BaseKeyedObjectPool
Parameters:
key - the key used to obtain the object
obj - a borrowed instance to be returned.

setFactory

public void setFactory(KeyedPoolableObjectFactory factory)
            throws IllegalStateException
Sets the factory I use to create new instances (optional operation).
Specified by:
setFactory in interface KeyedObjectPool
Overrides:
setFactory in interface BaseKeyedObjectPool
Parameters:
factory - the KeyedPoolableObjectFactory I use to create new instances.

toString

public String toString()

Copyright © 2001-2003 Apache Software Foundation. Documenation generated March 31 2006.