The POAD development process glues constructional design patterns. Interfaces qualify a constructional design pattern to be a unit for composition. In this appendix, we define interfaces for some of the patterns that we used in developing the applications in Part 4. There is no unique definition for interfaces of a specific pattern; a pattern can possess multiple interfaces.
The Strategy pattern has the class
Context as the interface to the encapsulated control strategy. One might also use the
ContextInterface() operation as an interface operation for the Strategy pattern.
The Observer has two interfaces that allow coordinating the subject observed with its ...