T
- Type of element pooled in this pool.public class SoftReferenceObjectPool<T> extends BaseObjectPool<T>
Constructor and Description |
---|
SoftReferenceObjectPool(PooledObjectFactory<T> factory)
Create a
SoftReferenceObjectPool with the specified factory. |
Modifier and Type | Method and Description |
---|---|
void |
addObject()
Creates an object, and places it into the pool. addObject() is useful for
"pre-loading" a pool with idle objects.
|
T |
borrowObject()
Borrows an object from the pool.
|
void |
clear()
Clears any objects sitting idle in the pool.
|
void |
close()
Closes this pool, and frees any resources associated with it.
|
PooledObjectFactory<T> |
getFactory()
Returns the
PooledObjectFactory used by this pool to create and
manage object instances. |
int |
getNumActive()
Returns the number of instances currently borrowed from this pool.
|
int |
getNumIdle()
Returns an approximation not less than the of the number of idle
instances in the pool.
|
void |
invalidateObject(T obj)
Invalidates an object from the pool.
|
void |
returnObject(T obj)
Returns an instance to the pool after successful validation and
passivation.
|
protected void |
toStringAppendFields(java.lang.StringBuilder builder)
Used by sub-classes to include the fields defined by the sub-class in the
BaseObject.toString() output. |
assertOpen, isClosed
toString
public SoftReferenceObjectPool(PooledObjectFactory<T> factory)
SoftReferenceObjectPool
with the specified factory.factory
- object factory to use.public T borrowObject() throws java.lang.Exception
PooledObjectFactory.makeObject()
method is invoked to create a
new instance.
All instances are activated
and validated
before being returned by this method. If validation fails or
an exception occurs activating or validating an idle instance, the
failing instance is destroyed
and another instance is retrieved from the pool, validated and
activated. This process continues until either the pool is empty or an
instance passes validation. If the pool is empty on activation or it does
not contain any valid instances, the factory's makeObject
method is used to create a new instance. If the created instance either
raises an exception on activation or fails validation,
NoSuchElementException
is thrown. Exceptions thrown by
MakeObject
are propagated to the caller; but other than
ThreadDeath
or VirtualMachineError
, exceptions
generated by activation, validation or destroy methods are swallowed
silently.
borrowObject
in interface ObjectPool<T>
borrowObject
in class BaseObjectPool<T>
java.util.NoSuchElementException
- if a valid object cannot be providedjava.lang.IllegalStateException
- if invoked on a closed
pooljava.lang.Exception
- if an exception occurs creating a new instancepublic void returnObject(T obj) throws java.lang.Exception
validation
fails
passivation
throws an exceptionreturnObject
in interface ObjectPool<T>
returnObject
in class BaseObjectPool<T>
obj
- instance to return to the pooljava.lang.IllegalStateException
- if an attempt is made to return an object to the pool that
is in any state other than allocated (i.e. borrowed).
Attempting to return an object more than once or attempting
to return an object that was never borrowed from the pool
will trigger this exception.java.lang.Exception
- if an instance cannot be returned to the poolpublic void invalidateObject(T obj) throws java.lang.Exception
By contract, obj
must have been obtained
using ObjectPool.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<T>
invalidateObject
in class BaseObjectPool<T>
obj
- a borrowed
instance to be disposed.java.lang.Exception
- if the instance cannot be invalidatedpublic void addObject() throws java.lang.Exception
Before being added to the pool, the newly created instance is
validated
and
passivated
. If
validation fails, the new instance is
destroyed
. Exceptions
generated by the factory makeObject
or
passivate
are propagated to the caller. Exceptions
destroying instances are silently swallowed.
addObject
in interface ObjectPool<T>
addObject
in class BaseObjectPool<T>
java.lang.IllegalStateException
- if invoked on a closed
pooljava.lang.Exception
- when the factory
has a problem creating
or passivating an object.public int getNumIdle()
getNumIdle
in interface ObjectPool<T>
getNumIdle
in class BaseObjectPool<T>
public int getNumActive()
getNumActive
in interface ObjectPool<T>
getNumActive
in class BaseObjectPool<T>
public void clear()
clear
in interface ObjectPool<T>
clear
in class BaseObjectPool<T>
public void close()
clear()
to destroy and remove instances in the pool.
Calling addObject()
or borrowObject()
after invoking this
method on a pool will cause them to throw an
IllegalStateException
.
close
in interface java.io.Closeable
close
in interface java.lang.AutoCloseable
close
in interface ObjectPool<T>
close
in class BaseObjectPool<T>
public PooledObjectFactory<T> getFactory()
PooledObjectFactory
used by this pool to create and
manage object instances.protected void toStringAppendFields(java.lang.StringBuilder builder)
BaseObject
BaseObject.toString()
output.toStringAppendFields
in class BaseObjectPool<T>
builder
- Field names and values are appended to this objectCopyright © 2000-2018 Apache Software Foundation. All Rights Reserved.