StackKeyedObjectPool (Apache Commons Object Pooling Package)

java.lang.Object
- org.apache.commons.pool.BaseKeyedObjectPool<K,V>
- - org.apache.commons.pool.impl.StackKeyedObjectPool<K,V>

Type Parameters:

K - the type of keys in this pool

V - the type of objects held in this pool

All Implemented Interfaces:

KeyedObjectPool<K,V>
```
public class StackKeyedObjectPool<K,V>
extends BaseKeyedObjectPool<K,V>
implements KeyedObjectPool<K,V>
```
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.

Since:

Pool 1.0

Version:

$Revision: 1222710 $ $Date: 2011-12-23 10:58:12 -0500 (Fri, 23 Dec 2011) $

Author:

Rodney Waldhoff, Sandy McArthur

See Also:

Stack

Constructor Summary

Constructors
Constructor and Description
`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<K,V> factory)` Create a new `SimpleKeyedObjectPool` using the specified `factory` to create new instances.
`StackKeyedObjectPool(KeyedPoolableObjectFactory<K,V> factory, int max)` Create a new `SimpleKeyedObjectPool` using the specified `factory` to create new instances.
`StackKeyedObjectPool(KeyedPoolableObjectFactory<K,V> factory, int max, int init)` Create a new `SimpleKeyedObjectPool` using the specified `factory` to create new instances.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`addObject(K key)` Create an object using the `factory`, passivate it, and then placed in the idle object pool.
`V`	`borrowObject(K key)` Borrows an object with the given key.
`void`	`clear()` Clears the pool, removing all pooled instances.
`void`	`clear(K key)` Clears the specified pool, removing all pooled instances corresponding to the given `key`.
`void`	`close()` Close this pool, and free any resources associated with it.
`Map<K,Integer>`	`getActiveCount()`
`KeyedPoolableObjectFactory<K,V>`	`getFactory()`
`int`	`getInitSleepingCapacity()`
`int`	`getMaxSleeping()`
`int`	`getNumActive()` Returns the total number of instances current borrowed from this pool but not yet returned.
`int`	`getNumActive(K key)` Returns the number of instances currently borrowed from but not yet returned to the pool corresponding to the given `key`.
`int`	`getNumIdle()` Returns the total number of instances currently idle in this pool.
`int`	`getNumIdle(K key)` Returns the number of instances corresponding to the given `key` currently idle in this pool.
`Map<K,Stack<V>>`	`getPools()`
`int`	`getTotActive()`
`int`	`getTotIdle()`
`void`	`invalidateObject(K key, V obj)` Invalidates an object from the pool.
`void`	`returnObject(K key, V obj)` Returns `obj` to the pool under `key`.
`String`	`toString()` Returns a string representation of this StackKeyedObjectPool, including the number of pools, the keys and the size of each keyed pool.

Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - StackKeyedObjectPool
```
public StackKeyedObjectPool()
```
    Create a new pool using no factory. Clients must first set the factory or may populate the pool using returnObject before they can be borrowed.
    
    See Also:
    
    StackKeyedObjectPool(KeyedPoolableObjectFactory), setFactory(KeyedPoolableObjectFactory)
  - StackKeyedObjectPool
```
public StackKeyedObjectPool(int max)
```
    Create a new pool using no factory. Clients must first set the factory or may populate the pool using returnObject before they can be borrowed.
    
    Parameters:
    
    max - cap on the number of "sleeping" instances in the pool
    
    See Also:
    
    StackKeyedObjectPool(KeyedPoolableObjectFactory, int), setFactory(KeyedPoolableObjectFactory)
  - StackKeyedObjectPool
```
public StackKeyedObjectPool(int max,
                            int init)
```
    Create a new pool using no factory. Clients must first set the factory or may populate the pool using returnObject 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.)
    
    See Also:
    
    StackKeyedObjectPool(KeyedPoolableObjectFactory, int, int), setFactory(KeyedPoolableObjectFactory)
  - StackKeyedObjectPool
```
public StackKeyedObjectPool(KeyedPoolableObjectFactory<K,V> 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<K,V> 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<K,V> 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 Detail
  - addObject
```
public void addObject(K key)
               throws Exception
```
    Create an object using the factory, passivate it, and then placed in the idle object pool. addObject is useful for "pre-loading" a pool with idle objects.
    
    Specified by:
    
    addObject in interface KeyedObjectPool<K,V>
    
    Overrides:
    
    addObject in class BaseKeyedObjectPool<K,V>
    
    Parameters:
    
    key - the key a new instance should be added to
    
    Throws:
    
    Exception - when KeyedPoolableObjectFactory.makeObject(K) fails.
    
    IllegalStateException - when no factory has been set or after close() has been called on this pool.
  - borrowObject
```
public V borrowObject(K key)
               throws Exception
```
    Borrows an object with the given key. If there are no idle instances under the given key, a new one is created.
    
    Specified by:
    
    borrowObject in interface KeyedObjectPool<K,V>
    
    Specified by:
    
    borrowObject in class BaseKeyedObjectPool<K,V>
    
    Parameters:
    
    key - the pool key
    
    Returns:
    
    keyed poolable object instance
    
    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
  - clear
```
public void clear()
```
    Clears the pool, removing all pooled instances.
    
    Specified by:
    
    clear in interface KeyedObjectPool<K,V>
    
    Overrides:
    
    clear in class BaseKeyedObjectPool<K,V>
  - clear
```
public void clear(K key)
```
    Clears the specified pool, removing all pooled instances corresponding to the given key.
    
    Specified by:
    
    clear in interface KeyedObjectPool<K,V>
    
    Overrides:
    
    clear in class BaseKeyedObjectPool<K,V>
    
    Parameters:
    
    key - the key to clear
  - close
```
public void close()
           throws Exception
```
    Close this pool, and free any resources associated with it.
    Calling addObject or borrowObject after invoking this method on a pool will cause them to throw an IllegalStateException.
    
    Specified by:
    
    close in interface KeyedObjectPool<K,V>
    
    Overrides:
    
    close in class BaseKeyedObjectPool<K,V>
    
    Throws:
    
    Exception - deprecated: implementations should silently fail if not all resources can be freed.
  - getActiveCount
```
public Map<K,Integer> getActiveCount()
```
    Returns:
    
    the _activeCount
    
    Since:
    
    1.5.5
  - getFactory
```
public KeyedPoolableObjectFactory<K,V> getFactory()
```
    Returns:
    
    the KeyedPoolableObjectFactory used by this pool to manage object instances.
    
    Since:
    
    1.5.5
  - getInitSleepingCapacity
```
public int getInitSleepingCapacity()
```
    Returns:
    
    the initial capacity of each pool.
    
    Since:
    
    1.5.5
  - getMaxSleeping
```
public int getMaxSleeping()
```
    Returns:
    
    the cap on the number of "sleeping" instances in each pool.
    
    Since:
    
    1.5.5
  - getNumActive
```
public int getNumActive()
```
    Returns the total number of instances current borrowed from this pool but not yet returned.
    
    Specified by:
    
    getNumActive in interface KeyedObjectPool<K,V>
    
    Overrides:
    
    getNumActive in class BaseKeyedObjectPool<K,V>
    
    Returns:
    
    the total number of instances currently borrowed from this pool
  - getNumActive
```
public int getNumActive(K key)
```
    Returns the number of instances currently borrowed from but not yet returned to the pool corresponding to the given key.
    
    Specified by:
    
    getNumActive in interface KeyedObjectPool<K,V>
    
    Overrides:
    
    getNumActive in class BaseKeyedObjectPool<K,V>
    
    Parameters:
    
    key - the key to query
    
    Returns:
    
    the number of instances corresponding to the given key currently borrowed in this pool
  - getNumIdle
```
public int getNumIdle()
```
    Returns the total number of instances currently idle in this pool.
    
    Specified by:
    
    getNumIdle in interface KeyedObjectPool<K,V>
    
    Overrides:
    
    getNumIdle in class BaseKeyedObjectPool<K,V>
    
    Returns:
    
    the total number of instances currently idle in this pool
  - getNumIdle
```
public int getNumIdle(K key)
```
    Returns the number of instances corresponding to the given key currently idle in this pool.
    
    Specified by:
    
    getNumIdle in interface KeyedObjectPool<K,V>
    
    Overrides:
    
    getNumIdle in class BaseKeyedObjectPool<K,V>
    
    Parameters:
    
    key - the key to query
    
    Returns:
    
    the number of instances corresponding to the given key currently idle in this pool
  - getPools
```
public Map<K,Stack<V>> getPools()
```
    Returns:
    
    map of keyed pools
    
    Since:
    
    1.5.5
  - getTotActive
```
public int getTotActive()
```
    Returns:
    
    the _totActive
  - getTotIdle
```
public int getTotIdle()
```
    Returns:
    
    the _totIdle
  - invalidateObject
```
public void invalidateObject(K key,
                             V 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<K,V>
    
    Specified by:
    
    invalidateObject in class BaseKeyedObjectPool<K,V>
    
    Parameters:
    
    key - the key used to obtain the object
    
    obj - a borrowed instance to be returned.
    
    Throws:
    
    Exception
  - returnObject
```
public void returnObject(K key,
                         V obj)
                  throws Exception
```
    Returns obj to the pool under key. If adding the returning instance to the pool results in maxSleeping exceeded for the given key, the oldest instance in the idle object pool is destroyed to make room for the returning instance.
    
    Specified by:
    
    returnObject in interface KeyedObjectPool<K,V>
    
    Specified by:
    
    returnObject in class BaseKeyedObjectPool<K,V>
    
    Parameters:
    
    key - the pool key
    
    obj - returning instance
    
    Throws:
    
    Exception
  - toString
```
public String toString()
```
    Returns a string representation of this StackKeyedObjectPool, including the number of pools, the keys and the size of each keyed pool.
    
    Overrides:
    
    toString in class Object
    
    Returns:
    
    Keys and pool sizes

Class StackKeyedObjectPool<K,V>

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

StackKeyedObjectPool

StackKeyedObjectPool

StackKeyedObjectPool

StackKeyedObjectPool

StackKeyedObjectPool

StackKeyedObjectPool

Method Detail

addObject

borrowObject

clear

clear

close

getActiveCount

getFactory

getInitSleepingCapacity

getMaxSleeping

getNumActive

getNumActive

getNumIdle

getNumIdle

getPools

getTotActive

getTotIdle

invalidateObject

returnObject

toString