org.apache.qpid.jms.util

Class FactoryFinder<T>

java.lang.Object

org.apache.qpid.jms.util.FactoryFinder<T>

Type Parameters:

T - The type of the object Factory to locate.

public class FactoryFinder<T>
extends Object

A Factory finding helper class used to locate objects that serve as Factories for other Object types. The search an instantiate mechanism is configurable so that in a non-stand-alone environment such as OSGI the finder and be configured to work.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	FactoryFinder.ObjectFactory The strategy that the FactoryFinder uses to find load and instantiate Objects can be changed out by calling the setObjectFactory(org.apache.qpid.jms.util.FactoryFinder.ObjectFactory) method with a custom implementation of ObjectFactory.
protected static class	FactoryFinder.StandaloneObjectFactory The default implementation of Object factory which works well in stand-alone applications.

Constructor Summary

Constructors

Constructor and Description
FactoryFinder(Class<T> factoryType, String path) Creates a new instance of the FactoryFinder using the given search path.

Method Summary

Modifier and Type	Method and Description
static FactoryFinder.ObjectFactory	getObjectFactory()
T	newInstance(String key) Creates a new instance of the given key.
void	registerProviderFactory(String scheme, T factory) Allow registration of a Provider factory without wiring via META-INF classes
static void	setObjectFactory(FactoryFinder.ObjectFactory objectFactory) Sets the ObjectFactory instance to use when searching for the Factory class.

Methods inherited from class java.lang.Object

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

Constructor Detail

FactoryFinder

public FactoryFinder(Class<T> factoryType,
                     String path)

Creates a new instance of the FactoryFinder using the given search path.

Parameters:

factoryType - The Class that defines what this finder is searching for.

path - The path to use when searching for the factory definitions.

Method Detail

getObjectFactory

public static FactoryFinder.ObjectFactory getObjectFactory()

Returns:

the currently configured ObjectFactory instance used to locate the Factory objects.

setObjectFactory

public static void setObjectFactory(FactoryFinder.ObjectFactory objectFactory)

Sets the ObjectFactory instance to use when searching for the Factory class. This allows the default instance to be overridden in an environment where the basic version will not work.

Parameters:

objectFactory - the new object factory to use when searching for a Factory instance.

newInstance

public T newInstance(String key)
              throws IllegalAccessException,
                     InstantiationException,
                     IOException,
                     ClassNotFoundException,
                     ClassCastException,
                     ResourceNotFoundException,
                     InvocationTargetException,
                     NoSuchMethodException,
                     SecurityException

Creates a new instance of the given key. The method first checks the cache of previously found factory instances for one that matches the key. If no cached version exists then the factory will be searched for using the configured ObjectFactory instance.

Parameters:

key - is the key to add to the path to find a text file containing the factory name

Returns:

a newly created instance

Throws:

IllegalAccessException - if an error occurs while accessing the search path.

InstantiationException - if the factory object fails on create.

ResourceNotFoundException - if the resource with the given key does not exist.

IOException - if the search encounter an IO error.

ClassNotFoundException - if the class that is to be loaded cannot be found.

ClassCastException - if the found object is not assignable to the request factory type.

InvocationTargetException - if the constructor of the found factory throws an exception

NoSuchMethodException - if the factory class found does not have a suitable constructor

SecurityException - if a security error occurs trying to create the factory instance.

registerProviderFactory

public void registerProviderFactory(String scheme,
                                    T factory)

Allow registration of a Provider factory without wiring via META-INF classes

Parameters:

scheme - The URI scheme value that names the target Provider instance.

factory - The factory to register in this finder.