Architectural Patterns

Factory method (virtual constructor)

This pattern suggests to let the subclasses instantiate the needed classes. The factory method defines an interface, but the instantiation is done by subclasses:

The preceding structure depicts a factory method, and an application uses a factory to create subtypes with an interface.

The benefits of using this are as listed:

• Loose coupling: Separates application from the classes and subclasses
• Customization hooks: The factory method gives subclasses a hook for providing an extended version of an object

The impact of using this is that it creates parallel class hierarchies (mirroring each other's structures), ...