Responsibility Driven Design (RDD)

Definition

Developed by Rebecca Wirfs-Brock, et al., Responsibility Driven Design (RDD) is a software development method that, like XP, has its origins in the Smalltalk community. Compared to data driven and use case driven design methods, RDD promotes the production of pure object-oriented designs that:

• Maximize Abstraction, Cohesion, and Understandability
• Minimize Coupling and Maintenance

Object Modeling

Where RDD fits into object modeling (in rough order of occurance, assuming iteration):

1. Name the role (class/interface) on diagram during whiteboarding
2. Define the role in Project Glossary
3. Stereotype the role in class comment (RDD)
4. Capture the responsibilties on CRC card during whiteboarding, in class comment during coding (RDD)
5. Capture the public interface during coding
6. Specify the public interface with assertions and exceptions during coding (DBC)
7. Develop the unit tests during coding (XP)
8. Develop the implementation during coding
9. Run the unit tests

Incorporation into OPF

The following documents where RDD fits into the OPEN Process Framework:

• It is one of the major sources (along with RUP, XP, DBC).
• OPF incorporates the following aspects of RDD:
  • Roles
  • Responsibilities
  • Stereotypes
  • Architecture Guidelines
• Initiation Phase:
  • Requirements Engineering Activity:
    • Responsibilities of Actors in the Use Case Modeling section of the System Requirements Specification
    • Stereotypes, responsibilities, and OO architecture guidelines of essential types in the Domain Model Document
  • System Architecture:
    • Responsibilities of essential system components
  • Software Design:
    • Stereotypes, responsibilities, and OO architecture guidelines of classes and interfaces in the design documents
  • Software Implementation:
    • Stereotypes and responsibilities documented in the class comments
• Construction Phase:
  • Requirements Engineering Activity:
    • Responsibilities of Actors in the Use Case Modeling section of the System Requirements Specification
    • Stereotypes, responsibilities, and OO architecture guidelines of essential roles in the Domain Model Document
  • System Architecture:
    • Responsibilities of essential system components
  • Software Design:
    • Stereotypes, responsibilities, and OO architecture guidelines of classes and interfaces in the design documents
  • Software Implementation:
    • Stereotypes and responsibilities documented in the class comments