public interface KeyedObjectPool
A keyed pool pools instances of multiple types. Each type may be accessed using an arbitrary key.
Example of use:
Object obj =null
; Object key ="Key"
;try
{ obj = pool.borrowObject(key);//...use the object...
}catch
(Exception e) {// invalidate the object
pool.invalidateObject(key, obj);// do not return the object to the pool twice
obj =null
; }finally
{// make sure the object is returned to the pool
if
(null
!= obj) { pool.returnObject(key, obj); } }
KeyedObjectPool
implementations may choose to store at most
one instance per key value, or may choose to maintain a pool of instances
for each key (essentially creating a Map
of
pools
).
See BaseKeyedObjectPool
for a simple base implementation.
KeyedPoolableObjectFactory
,
KeyedObjectPoolFactory
,
ObjectPool
,
BaseKeyedObjectPool
Modifier and Type | Method and Description |
---|---|
void |
addObject(java.lang.Object key)
Create an object using the
factory or other
implementation dependent mechanism, passivate it, and then place it in the idle object pool. |
java.lang.Object |
borrowObject(java.lang.Object key)
Obtains an instance from this pool for the specified
key . |
void |
clear()
Clears the pool, removing all pooled instances (optional operation).
|
void |
clear(java.lang.Object key)
Clears the specified pool, removing all
pooled instances corresponding to
the given
key (optional operation). |
void |
close()
Close this pool, and free any resources associated with it.
|
int |
getNumActive()
Returns the total number of instances
current borrowed from this pool but not
yet returned (optional operation).
|
int |
getNumActive(java.lang.Object key)
Returns the number of instances
currently borrowed from but not yet returned
to the pool corresponding to the
given
key (optional operation). |
int |
getNumIdle()
Returns the total number of instances
currently idle in this pool (optional operation).
|
int |
getNumIdle(java.lang.Object key)
Returns the number of instances
corresponding to the given
key
currently idle in this pool (optional operation). |
void |
invalidateObject(java.lang.Object key,
java.lang.Object obj)
Invalidates an object from the pool
By contract,
obj must have been obtained
using borrowObject
or a related method as defined in an implementation
or sub-interface
using a key that is equivalent to the one used to
borrow the Object in the first place. |
void |
returnObject(java.lang.Object key,
java.lang.Object obj)
Return an instance to the pool.
|
void |
setFactory(KeyedPoolableObjectFactory factory)
Sets the
factory the pool uses
to create new instances (optional operation). |
void addObject(java.lang.Object key) throws java.lang.Exception, java.lang.IllegalStateException, java.lang.UnsupportedOperationException
factory
or other
implementation dependent mechanism, passivate it, and then place it in the idle object pool.
addObject
is useful for "pre-loading" a pool with idle objects
(Optional operation).key
- the key a new instance should be added tojava.lang.Exception
- when KeyedPoolableObjectFactory.makeObject(java.lang.Object)
fails.java.lang.IllegalStateException
- after close()
has been called on this pool.java.lang.UnsupportedOperationException
- when this pool cannot add new idle objects.java.lang.Object borrowObject(java.lang.Object key) throws java.lang.Exception, java.util.NoSuchElementException, java.lang.IllegalStateException
key
.
Instances returned from this method will have been either newly created with
makeObject
or will be a previously idle object and
have been activated with activateObject
and
then validated with validateObject
.
By contract, clients must return the borrowed object using
returnObject
, invalidateObject
, or a related method
as defined in an implementation or sub-interface,
using a key
that is equivalent
to the one used to
borrow the instance in the first place.
The behaviour of this method when the pool has been exhausted
is not strictly specified (although it may be specified by implementations).
Older versions of this method would return null
to indicate exhaustion,
newer versions are encouraged to throw a NoSuchElementException
.
key
- the key used to obtain the objectjava.lang.IllegalStateException
- after close
has been called on this pooljava.lang.Exception
- when makeObject
throws an exceptionjava.util.NoSuchElementException
- when the pool is exhausted and cannot or will not return another instancevoid clear() throws java.lang.Exception, java.lang.UnsupportedOperationException
UnsupportedOperationException
if the pool cannot be cleared.java.lang.UnsupportedOperationException
- when this implementation doesn't support the operationjava.lang.Exception
void clear(java.lang.Object key) throws java.lang.Exception, java.lang.UnsupportedOperationException
key
(optional operation).
Throws UnsupportedOperationException
if the pool cannot be cleared.key
- the key to clearjava.lang.UnsupportedOperationException
- when this implementation doesn't support the operationjava.lang.Exception
void close() throws java.lang.Exception
Calling addObject
or borrowObject
after invoking
this method on a pool will cause them to throw an IllegalStateException
.
java.lang.Exception
int getNumActive() throws java.lang.UnsupportedOperationException
java.lang.UnsupportedOperationException
- deprecated: when this implementation doesn't support the operationint getNumActive(java.lang.Object key) throws java.lang.UnsupportedOperationException
key
(optional operation).
Returns a negative value if this information is not available.key
- the key to querykey
currently borrowed in this pool or a negative value if unsupportedjava.lang.UnsupportedOperationException
- deprecated: when this implementation doesn't support the operationint getNumIdle() throws java.lang.UnsupportedOperationException
java.lang.UnsupportedOperationException
- deprecated: when this implementation doesn't support the operationint getNumIdle(java.lang.Object key) throws java.lang.UnsupportedOperationException
key
currently idle in this pool (optional operation).
Returns a negative value if this information is not available.key
- the key to querykey
currently idle in this pool or a negative value if unsupportedjava.lang.UnsupportedOperationException
- deprecated: when this implementation doesn't support the operationvoid invalidateObject(java.lang.Object key, java.lang.Object obj) throws java.lang.Exception
obj
must have been obtained
using borrowObject
or a related method as defined in an implementation
or sub-interface
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.
key
- the key used to obtain the objectobj
- a borrowed
instance to be returned.java.lang.Exception
void returnObject(java.lang.Object key, java.lang.Object obj) throws java.lang.Exception
obj
must have been obtained
using borrowObject
or a related method as defined in an implementation
or sub-interface
using a key
that is equivalent to the one used to
borrow the instance in the first place.key
- the key used to obtain the objectobj
- a borrowed
instance to be returned.java.lang.Exception
void setFactory(KeyedPoolableObjectFactory factory) throws java.lang.IllegalStateException, java.lang.UnsupportedOperationException
factory
the pool uses
to create new instances (optional operation).
Trying to change the factory
after a pool has been used will frequently
throw an UnsupportedOperationException
. It is up to the pool
implementation to determine when it is acceptable to call this method.factory
- the KeyedPoolableObjectFactory
used to create new instances.java.lang.IllegalStateException
- when the factory cannot be set at this timejava.lang.UnsupportedOperationException
- when this implementation doesn't support the operationCopyright © 2001-2003 Apache Software Foundation. Documenation generated February 3 2016.