T
- Type of element managed in this factory.public interface PooledObjectFactory<T>
ObjectPool
.
By contract, when an ObjectPool
delegates to a
PooledObjectFactory
,
makeObject()
is called whenever a new instance is needed.
activateObject(org.apache.tomcat.dbcp.pool2.PooledObject<T>)
is invoked on every instance that has been
passivated
before it is
borrowed
from the pool.
validateObject(org.apache.tomcat.dbcp.pool2.PooledObject<T>)
may be invoked on activated
instances to make sure they can be borrowed
from the pool. validateObject(org.apache.tomcat.dbcp.pool2.PooledObject<T>)
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(org.apache.tomcat.dbcp.pool2.PooledObject<T>)
is invoked on every instance when it is returned
to the pool.
destroyObject(org.apache.tomcat.dbcp.pool2.PooledObject<T>)
is invoked on every instance when it is being
"dropped" from the pool (whether due to the response from
validateObject(org.apache.tomcat.dbcp.pool2.PooledObject<T>)
, 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.
PooledObjectFactory
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.
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 information about the objects that
they manage.
ObjectPool
Modifier and Type | Method and Description |
---|---|
void |
activateObject(PooledObject<T> p)
Reinitializes an instance to be returned by the pool.
|
void |
destroyObject(PooledObject<T> p)
Destroys an instance no longer needed by the pool.
|
PooledObject<T> |
makeObject()
Creates an instance that can be served by the pool and wrap it in a
PooledObject to be managed by the pool. |
void |
passivateObject(PooledObject<T> p)
Uninitializes an instance to be returned to the idle object pool.
|
boolean |
validateObject(PooledObject<T> p)
Ensures that the instance is safe to be returned by the pool.
|
PooledObject<T> makeObject() throws java.lang.Exception
PooledObject
to be managed by the pool.PooledObject
wrapping an instance that can be served by the pooljava.lang.Exception
- if there is a problem creating a new instance,
this will be propagated to the code requesting an object.void destroyObject(PooledObject<T> p) 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.
p
- a PooledObject
wrapping the instance to be destroyedjava.lang.Exception
- should be avoided as it may be swallowed by
the pool implementation.validateObject(org.apache.tomcat.dbcp.pool2.PooledObject<T>)
,
ObjectPool.invalidateObject(T)
boolean validateObject(PooledObject<T> p)
p
- a PooledObject
wrapping the instance to be validatedfalse
if obj
is not valid and should
be dropped from the pool, true
otherwise.void activateObject(PooledObject<T> p) throws java.lang.Exception
p
- a PooledObject
wrapping the instance to be activatedjava.lang.Exception
- if there is a problem activating obj
,
this exception may be swallowed by the pool.destroyObject(org.apache.tomcat.dbcp.pool2.PooledObject<T>)
void passivateObject(PooledObject<T> p) throws java.lang.Exception
p
- a PooledObject
wrapping the instance to be passivatedjava.lang.Exception
- if there is a problem passivating obj
,
this exception may be swallowed by the pool.destroyObject(org.apache.tomcat.dbcp.pool2.PooledObject<T>)
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