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java.lang.Objectorg.apache.commons.pool.BaseObjectPool
org.apache.commons.pool.impl.StackObjectPool
public class StackObjectPool
A simple, Stack
-based ObjectPool
implementation.
Given a PoolableObjectFactory
, this class will maintain
a simple pool of instances. A finite number of "sleeping"
or idle instances is enforced, but when the pool is
empty, new instances are created to support the new load.
Hence this class places no limit on the number of "active"
instances created by the pool, but is quite useful for
re-using Objects without introducing
artificial limits.
Constructor Summary | |
---|---|
StackObjectPool()
Create a new pool using no factory. |
|
StackObjectPool(int maxIdle)
Create a new pool using no factory. |
|
StackObjectPool(int maxIdle,
int initIdleCapacity)
Create a new pool using no factory. |
|
StackObjectPool(PoolableObjectFactory factory)
Create a new StackObjectPool using the specified factory to create new instances. |
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StackObjectPool(PoolableObjectFactory factory,
int maxIdle)
Create a new SimpleObjectPool using the specified factory to create new instances, capping the number of "sleeping" instances to max. |
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StackObjectPool(PoolableObjectFactory factory,
int maxIdle,
int initIdleCapacity)
Create a new SimpleObjectPool using the specified factory to create new instances, capping the number of "sleeping" instances to max, and initially allocating a container capable of containing at least init instances. |
Method Summary | |
---|---|
void |
addObject()
Create an object, and place it into the pool. |
java.lang.Object |
borrowObject()
Obtains an instance from this pool. |
void |
clear()
Clears any objects sitting idle in the pool. |
void |
close()
Close this pool, and free any resources associated with it. |
int |
getNumActive()
Return the number of instances currently borrowed from this pool. |
int |
getNumIdle()
Return the number of instances currently idle in this pool. |
void |
invalidateObject(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. |
void |
returnObject(java.lang.Object obj)
Return an instance to the pool. |
void |
setFactory(PoolableObjectFactory factory)
Sets the factory this pool uses
to create new instances. |
Methods inherited from class java.lang.Object |
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equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
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public StackObjectPool()
set the factory
else this pool will not behave correctly.
Clients may first populate the pool
using returnObject(java.lang.Object)
before they can be borrowed
but this useage is discouraged.
StackObjectPool(PoolableObjectFactory)
public StackObjectPool(int maxIdle)
set the factory
else this pool will not behave correctly.
Clients may first populate the pool
using returnObject(java.lang.Object)
before they can be borrowed
but this useage is discouraged.
maxIdle
- cap on the number of "sleeping" instances in the poolStackObjectPool(PoolableObjectFactory, int)
public StackObjectPool(int maxIdle, int initIdleCapacity)
set the factory
else this pool will not behave correctly.
Clients may first populate the pool
using returnObject(java.lang.Object)
before they can be borrowed
but this useage is discouraged.
maxIdle
- cap on the number of "sleeping" instances in the poolinitIdleCapacity
- initial size of the pool (this specifies the size of the container,
it does not cause the pool to be pre-populated.)StackObjectPool(PoolableObjectFactory, int, int)
public StackObjectPool(PoolableObjectFactory factory)
factory
- the PoolableObjectFactory
used to populate the poolpublic StackObjectPool(PoolableObjectFactory factory, int maxIdle)
factory
- the PoolableObjectFactory
used to populate the poolmaxIdle
- cap on the number of "sleeping" instances in the poolpublic StackObjectPool(PoolableObjectFactory factory, int maxIdle, int initIdleCapacity)
factory
- the PoolableObjectFactory
used to populate the poolmaxIdle
- cap on the number of "sleeping" instances in the poolinitIdleCapacity
- initial size of the pool (this specifies the size of the container,
it does not cause the pool to be pre-populated.)Method Detail |
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public void addObject() throws java.lang.Exception
addObject
in interface ObjectPool
addObject
in class BaseObjectPool
java.lang.Exception
- when the _factory
has a problem creating an object.public java.lang.Object borrowObject() throws java.lang.Exception
ObjectPool
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 instance using
returnObject
, invalidateObject
, or a related method
as defined in an implementation or sub-interface.
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
.
borrowObject
in interface ObjectPool
borrowObject
in class BaseObjectPool
java.lang.IllegalStateException
- after close
has been called on this pool.
java.lang.Exception
- when makeObject
throws an exception.
java.util.NoSuchElementException
- when the pool is exhausted and cannot or will not return another instance.public void clear()
clear
in interface ObjectPool
clear
in class BaseObjectPool
public void close() throws java.lang.Exception
Calling addObject()
or borrowObject()
after invoking
this method on a pool will cause them to throw an
IllegalStateException
.
close
in interface ObjectPool
close
in class BaseObjectPool
java.lang.Exception
- deprecated: implementations should silently fail if not all resources can be freed.public int getNumActive()
getNumActive
in interface ObjectPool
getNumActive
in class BaseObjectPool
public int getNumIdle()
getNumIdle
in interface ObjectPool
getNumIdle
in class BaseObjectPool
public void invalidateObject(java.lang.Object obj) throws java.lang.Exception
ObjectPool
obj
must have been obtained
using borrowObject
or a related method as defined in an implementation
or sub-interface.
This method should be used when an object that has been borrowed is determined (due to an exception or other problem) to be invalid.
invalidateObject
in interface ObjectPool
invalidateObject
in class BaseObjectPool
obj
- a borrowed
instance to be disposed.
java.lang.Exception
- deprecated: as of Pool 2.0 pool implementations should swallow
exceptions that occur when a poolable object is returned. For future source compatability
implementations of this method should not even declare that they throw any exception.public void returnObject(java.lang.Object obj) throws java.lang.Exception
ObjectPool
obj
must have been obtained
using borrowObject
or a related method as defined in an implementation
or sub-interface.
returnObject
in interface ObjectPool
returnObject
in class BaseObjectPool
obj
- a borrowed
instance to be returned.
java.lang.Exception
- deprecated: as of Pool 2.0 pool implementations should swallow
exceptions that occur when a poolable object is returned. For future source compatability
implementations of this method should not even declare that they throw any exception.public void setFactory(PoolableObjectFactory factory) throws java.lang.IllegalStateException
factory
this pool uses
to create new instances. Trying to change
the factory
while there are borrowed objects will
throw an IllegalStateException
.
setFactory
in interface ObjectPool
setFactory
in class BaseObjectPool
factory
- the PoolableObjectFactory
used to create new instances.
java.lang.IllegalStateException
- when the factory cannot be set at this time
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