net.sf.sasl.common.pool
Class SingletonPool

java.lang.Object
  net.sf.sasl.common.pool.AbstractPool<Class<?>,Object>
      net.sf.sasl.common.pool.SingletonPool

public class SingletonPool
extends AbstractPool<Class<?>,Object>

The class could be used to create and share singleton instances without the need to define a static singleton creation procedure at the singleton class.

Since:

0.0.2 (sasl-common-library)

Author:

Philipp Förmer

Nested Class Summary

Nested classes/interfaces inherited from class net.sf.sasl.common.pool.AbstractPool

AbstractPool.PoolEntry<V>

Constructor Summary

SingletonPool()

Method Summary

<T> void	free(Class<T> clazz, T instance) Notifies the pool that a reference under the given key is no longer needed.
static SingletonPool	getSharedInstance() Returns a shared instance of the SingletonPool.
<T> T	retrieveSingleton(Class<T> clazz) Returns a pooled singleton instance of the given class.

Methods inherited from class net.sf.sasl.common.pool.AbstractPool

add, containsKey, free, getPoolEntry, retrieve

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

SingletonPool

public SingletonPool()

Method Detail

getSharedInstance

public static SingletonPool getSharedInstance()

Returns a shared instance of the SingletonPool.

Returns:

non null.

Since:

0.0.2 (sasl-common-library)

retrieveSingleton

public <T> T retrieveSingleton(Class<T> clazz)
                    throws IllegalArgumentException,
                           ReflectionException

Returns a pooled singleton instance of the given class. If no singleton instance was yet created for the given class, than a new one will be instantiated via reflection. As of this, the class should define a zero argument constructor, otherwise the instantiation will fail.

Type Parameters:

T -

Parameters:

clazz - non null

Returns:

non null pooled instance.

Throws:

IllegalArgumentException - if parameter clazz is null.

ReflectionException - if an error occured during creating a not yet pooled singleton instance.

Since:

0.0.2 (sasl-common-library)

free

public <T> void free(Class<T> clazz,
                     T instance)

Notifies the pool that a reference under the given key is no longer needed. The instance must be same to the instance the key points to. This allows the pool to free pooled instances from the pool so that they could get garbage collected.

Type Parameters:

T -

Parameters:

clazz - null or non null.

instance - null or non null.

Since:

0.0.2 (sasl-common-library)