Interface KeyedPooledObjectFactory<K,V>

Type Parameters:
K - The type of keys managed by this factory.
V - Type of element managed by this factory.
All Known Implementing Classes:

public interface KeyedPooledObjectFactory<K,V>
An interface defining life-cycle methods for instances to be served by a KeyedObjectPool.

By contract, when an KeyedObjectPool delegates to a KeyedPooledObjectFactory,

  1. makeObject(K) is called whenever a new instance is needed.
  2. activateObject(K, org.apache.commons.pool2.PooledObject<V>) is invoked on every instance that has been passivated before it is borrowed from the pool.
  3. validateObject(K, org.apache.commons.pool2.PooledObject<V>) may be invoked on activated instances to make sure they can be borrowed from the pool. validateObject may also be used to test an instance being returned to the pool before it is passivated. It will only be invoked on an activated instance.
  4. passivateObject is invoked on every instance when it is returned to the pool.
  5. destroyObject is invoked on every instance when it is being "dropped" from the pool (whether due to the response from validateObject, or for reasons specific to the pool implementation.) There is no guarantee that the instance being destroyed will be considered active, passive or in a generally consistent state.
KeyedPooledObjectFactory must be thread-safe. The only promise an KeyedObjectPool makes is that the same instance of an object will not be passed to more than one method of a KeyedPooledObjectFactory at a time.

While clients of a KeyedObjectPool borrow and return instances of the underlying value type V, the factory methods act on instances of PooledObject<V>. These are the object wrappers that pools use to track and maintain state informations about the objects that they manage.

See Also: