Wednesday 17 January 2007

Factory Method Pattern vs. Abstract Factory Pattern

The Factory Method pattern is to define an interface for creating an object but let subclasses decide the class to instantiate. For example the UIBuilder class contains two method stubs. The subclasses (EnglishUIBuilder, MalayUIBuilder) have to implement these stubs in their own way.

The Abstract Factory pattern is to provide an interface for creating families of related or dependent objects without specifying their concrete classes. This pattern is often used in conjunction with the Factory Method pattern, thus it can be seen as a factory of factory objects.

The UIFactory static method returns a subclass of UIFactory which in turn creates the appropriate UIBuilder object. The UIFactory subclass returned is determined by reading a config file and using the default value.

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