Factory Method Pattern

Summary

• The Factory Method pattern is a way of creating objects, but letting subclasses decide exactly which class to instantiate.
• The Factory Method pattern is a lightweight pattern that achieves independence from application-specific classes. The client programs to the interface and lets the pattern sort out the rest.

Class diagram: (see Factory Method Pattern code review)

Usage

Use the Factory Method pattern when:

• Flexibility is important.
• Objects can be extended in subclasses.
• There is a specific reason why one subclass would be chosen over another (this logic forms part of the Factory Method).
• A client delegates responsibilities to subclasses in parallel hierarchies.