Jakarta Commons Object Pooling Package

Generic Object pooling API with several implementations.

The org.apache.commons.pool package defines a simple interface for a pool of object instances, and a handful of base classes that may be useful when creating pool implementations. The api supports pooling of unique objects which can be requested via a key as well as pools where all objects are equivalent.

The org.apache.commons.pool.impl package contains several pool implementations. StackObjectPool is useful for supporting reuse of a limited number of instances while allowing new instances to be created as needed to support high demand. GenericObjectPool has many configuration options and can support a limited set of objects such as would be useful in a database connection pool. SoftReferenceObjectPool has no limit on the number of objects in the pool, but garbage collector can remove idle objects from the pool as needed. There are also keyed versions of the first two.

Here is a simple example of pooling HashMap's. First create an ObjectPoolFactory

public class HashMapFactory 
extends BasePoolableObjectFactory
{
/**
 Creates an instance that can be returned by the pool.