Pluggable Factory
Pluggable FactoryAn extension to the AbstractFactoryPattern is the PluggableFactory proposed by JohnVlissides. See:
Briefly, there is a single factory class, instances of which contain prototype instances of the things to be created; these instances are then cloned to satisfy creation requests. Thus, the PluggableFactory pattern hides the PrototypePattern, using the factory as a facade (FacadePattern).
For example (in JavaLanguage):
abstract class Button
{
abstract public Object clone();
}
class WindowsButton extends Button
{
// implementation of a Windows button
}
class MotifButton extends Button
{
// implementation of a Motif button
}
class ButtonFactory
{
private Button btn ;
public Button create()
{
return (Button)btn.clone() ;
}
}
The normal AbstractFactory approach would make ButtonFactory abstract, and then add WindowsButtonFactory and MotifButtonFactory subclasses; it also wouldn't need Button to be Cloneable.
The advantage of a PluggableFactory is that it eliminates the proliferation of factory subclasses. The disadvantage is that the products must be cloneable, or otherwise duplicatable in some way.
A nominally related, but distinct, pattern for using AbstractFactory as the export component in PluginArchitecture is described in the page on AbstractFactory.
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(last edited May 10, 2010)
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