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public interface PoolableObjectFactory
An interface defining life-cycle methods for
 instances to be served by an ObjectPool.
 
 By contract, when an ObjectPool
 delegates to a PoolableObjectFactory,
 
makeObject
   is called whenever a new instance is needed.
  activateObject
   is invoked on every instance that has been
   passivated before it is
   borrowed from the pool.
  validateObject
   is 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.
  passivateObject
   is invoked on every instance when it is returned to the pool.
  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.
  
 PoolableObjectFactory must be thread-safe. The only promise
 an ObjectPool makes is that the same instance of an object will not
 be passed to more than one method of a PoolableObjectFactory
 at a time.
 
ObjectPool| Method Summary | |
|---|---|
|  void | activateObject(java.lang.Object obj)Reinitialize an instance to be returned by the pool. | 
|  void | destroyObject(java.lang.Object obj)Destroys an instance no longer needed by the pool. | 
|  java.lang.Object | makeObject()Creates an instance that can be served by the pool. | 
|  void | passivateObject(java.lang.Object obj)Uninitialize an instance to be returned to the idle object pool. | 
|  boolean | validateObject(java.lang.Object obj)Ensures that the instance is safe to be returned by the pool. | 
| Method Detail | 
|---|
void activateObject(java.lang.Object obj)
                    throws java.lang.Exception
obj - the instance to be activated
java.lang.Exception - if there is a problem activating obj,
    this exception may be swallowed by the pool.destroyObject(java.lang.Object)
void destroyObject(java.lang.Object obj)
                   throws java.lang.Exception
 It is important for implementations of this method to be aware
 that there is no guarantee about what state obj
 will be in and the implementation should be prepared to handle
 unexpected errors.
 
Also, an implementation must take in to consideration that instances lost to the garbage collector may never be destroyed.
obj - the instance to be destroyed
java.lang.Exception - should be avoided as it may be swallowed by
    the pool implementation.validateObject(java.lang.Object), 
ObjectPool.invalidateObject(java.lang.Object)
java.lang.Object makeObject()
                            throws java.lang.Exception
activated. They will not be
 activated before being served by the pool.
java.lang.Exception - if there is a problem creating a new instance,
    this will be propagated to the code requesting an object.
void passivateObject(java.lang.Object obj)
                     throws java.lang.Exception
obj - the instance to be passivated
java.lang.Exception - if there is a problem passivating obj,
    this exception may be swallowed by the pool.destroyObject(java.lang.Object)boolean validateObject(java.lang.Object obj)
false if obj should be destroyed.
obj - the instance to be validated
false if obj is not valid and should
         be dropped from the pool, true otherwise.| 
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