Appendix A. Techniques and Their Uses

Technique	Purpose
Activity Diagram	Shows behavior with control structure. Can show many objects over many uses, many objects in single use case, or implementation of method. Encourages parallel behavior.
Class Diagram	Shows static structure of concepts, types, and classes. Concepts show how users think about the world; types show interfaces of software components; classes show implementation of software components .
CRC Cards	Helps get to essence of class's purpose. Good for exploring how to implement use case. Use if getting bogged down with details or if learning object approach to design.
Deployment Diagram	Shows physical layout of components on hardware nodes.
Design by Contract	Provides rigorous definition of operation's purpose and class's legal state. Encode these in class to enhance debugging.
Interaction Diagram	Shows how several objects collaborate in single use case.
Package Diagram	Shows groups of classes and dependencies among them.
Patterns	Offers useful bits of analysis, design, and coding techniques. Good examples to learn from; starting point for designs.
Refactoring	Helps in making changes to working program to improve structure. Use when code is getting in the way of good design.
State Diagram	Shows how single object behaves across many use cases.
Use Case	Elicits requirements from users in meaningful chunks . Construction planning is built around delivering some use cases in each iteration. Basis for system testing.