com.bc.ceres.core

Class SingleTypeExtensionFactory<T,E>

java.lang.Object

com.bc.ceres.core.SingleTypeExtensionFactory<T,E>

All Implemented Interfaces:

ExtensionFactory

public class SingleTypeExtensionFactory<T,E>
extends Object
implements ExtensionFactory

An implementation of a ExtensionFactory for a single extension type.

Since:

Ceres 0.9

Version:

$Revision$ $Date$

Constructor Summary

Constructors

Constructor and Description
SingleTypeExtensionFactory(Class<E> extensionType) Constructs a SingleTypeExtensionFactory for extensions of the given type.
SingleTypeExtensionFactory(Class<E> extensionType, Class<? extends E> extensionSubType) Constructs a SingleTypeExtensionFactory for extensions of the given sub-type which implement the given type.

Method Summary

Modifier and Type	Method and Description
E	getExtension(Object object, Class<?> extensionType) Gets an instance of an extension type for the specified object of type T.
protected E	getExtensionImpl(T object, Class<E> extensionType) Creates an extension object for the given object.
Class<? extends E>	getExtensionSubType()
Class<E>	getExtensionType()
Class<?>[]	getExtensionTypes()

Methods inherited from class java.lang.Object

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

Constructor Detail

SingleTypeExtensionFactory

public SingleTypeExtensionFactory(Class<E> extensionType)

Constructs a SingleTypeExtensionFactory for extensions of the given type. The extensionSubType will be the same as the given type.

Parameters:

extensionType - The extension type.

SingleTypeExtensionFactory

public SingleTypeExtensionFactory(Class<E> extensionType,
                                  Class<? extends E> extensionSubType)

Constructs a SingleTypeExtensionFactory for extensions of the given sub-type which implement the given type.

Parameters:

extensionType - The extension type. Must be assignable from extensionSubType.

extensionSubType - The specific extension sub-type.

Method Detail

getExtensionType

public final Class<E> getExtensionType()

Returns:

The extension type.

getExtensionSubType

public final Class<? extends E> getExtensionSubType()

Returns:

The specific extension sub-type.

getExtension

public final E getExtension(Object object,
                            Class<?> extensionType)

Gets an instance of an extension type for the specified object of type T. If this factory's extensionType is assignable from the given extensionType, the method calls getExtensionImpl(Object, Class). Otherwise null is returned.

Specified by:

getExtension in interface ExtensionFactory

Parameters:

object - The object to be extended.

extensionType - The type of the requested extension.

Returns:

The extension object, or null if the given object is not extensible by this factory or if an error occurs during the call to getExtensionImpl(Object, Class).

getExtensionImpl

protected E getExtensionImpl(T object,
                             Class<E> extensionType)
                      throws Throwable

Creates an extension object for the given object. The new extension object must be an instance of the extensionSubType passed to the constructor. Called if, and only if this factory's extensionType is assignable from the given extensionType.

The default implementation returns a new instance of extensionSubType, either created from its public no-arg constructor or its public 1-arg constructor which can take the given object. Clients may subclass and override this method in order to implement a more sophisticated instance creation.

Parameters:

object - The object to be extended.

extensionType - The type of the requested extension.

Returns:

The extension object.

Throws:

Throwable - If an error occurs.

getExtensionTypes

public final Class<?>[] getExtensionTypes()

Specified by:

getExtensionTypes in interface ExtensionFactory

Returns:

The array containing the extensionType and optionally the extensionSubType supported by this factory.