Copyright ©2004 Cezary Z Janikow 1 OOAD Overview n OO language – Necessary for OO systems? – Sufficient for OO systems? Owning a hummer doesn’t make you a home builder n OOAD is necessary in building QUAILITY OO systems – Architectural cohesion – Reusability – Maintenance

Copyright ©2004 Cezary Z Janikow 2 OOAD Overview n Key importance – Assignment of Responsibilities Performed during Design workflow Responsibility-driven design Follows GRASP principles Successful designs become Patterns n Key elements and properties – Use Cases Text description of vital transactions and scenarios Not OO but usually used in OOAD – Agile Process Light, flexible, iterative form of the UP process Iterative – performed in a number of successive builds

Copyright ©2004 Cezary Z Janikow 3 OOAD Overview n OOAD elements

Copyright ©2004 Cezary Z Janikow 4 OOAD Overview n Analysis -> Design -> Implementation -> Deployment – Analysis is investigation of the problem, requirements, constraints, technology Emphasis on finding problem entities (conceptual classes), relationships, constraints – Design is a conceptual solution, including architecture, algorithms, etc. Emphasis on designing classes and objects with behavior to allow collaborations to solve particular requests while using patterns – Implementation is expression of the design in code Emphasis on utilizing the language of choice to implement design classes while exploring visibility, navigability, etc. – Deployment is the actual installation in the host environment

Copyright ©2004 Cezary Z Janikow 5 OOAD Overview n Airplane example of object and class discovery

Copyright ©2004 Cezary Z Janikow 6 OOAD Example n Rudimentary process – UseCases -> DomainModel -> Interactions -> DesignModel n Dice game example – 2 players rolling 2 dice n Use Case – Verbal description of transactions or processes – Player throws two dice. The result is observed. If the total is 7 the player wins otherwise he loses.

Copyright ©2004 Cezary Z Janikow 7 OOAD Example n Domain Model – Static view of classes and relations

Copyright ©2004 Cezary Z Janikow 8 OOAD Example n Interactions – Assignment of responsibilities among objects – Sequence or Communication diagrams

Copyright ©2004 Cezary Z Janikow 9 OOAD Example n Design Diagrams n Software classes with methods according to responsibilities and attributes according to visibility

Copyright ©2004 Cezary Z Janikow 10 UML n UML n Visual Modeling Language

Copyright ©2004 Cezary Z Janikow 11 UML n Three perspectives (and class meanings in diagrams) n Conceptual – described the real world entities n Specification – describes design entities but not tied to specific implementations n Implementation – describes particular implementations of the specification elements