1. Distributed Java Programming 107-198 Distributed Java Programming Class #1 August 20, 2002

2. Distributed Java Programming 107-198 What is UML?  Stands for Unified Modeling Language  It is a culmination of 15 years of effort to properly define and model object- oriented systems.  It is based on the OO Methodologies of:  Grady Booch (Clouds)  Ivar Jacobson (Use Cases)  James Rumbaugh (OMT)

3. Distributed Java Programming 107-198 Yeah, but What is UML?  UML is a modeling language.  It lets us takes a problem, visualize it and clearly understand it before we begin writing code.  UML consists of a lot of different tools. However we are going to focus on three core tools for use in this class:  Use Cases  Class Diagrams  Interaction Diagrams  Lets dive into it

4. Distributed Java Programming 107-198 Use Case and Use Case Analysis  Use cases are tool for capturing how a users interacts with an existing system or a new system that is being built.  A use case is a discrete and well- defined action that is carried out by a user to reach a specific goal.  Use cases usually involve two pieces of documentation:  A Use Case Diagram  A Use Case Specification Document

5. Distributed Java Programming 107-198 A Use Case Diagram

6. Distributed Java Programming 107-198 Use Case Piece: The Actor ►Actors are a role a user is playing in the system. ►An actor can carry out many tasks within a system. ►Actors do not have to be people. They can be other systems. ►Often times, particularly large projects listing the actors are a good place to start.

7. Distributed Java Programming 107-198 Use Case Piece: The Use Case ►Represents a discrete task to be carried out by end user. ►Can also represent a more complex task. ►Granularity is the key here. You use case diagram clearly communicate the major tasks in the application will carry out.

8. Distributed Java Programming 107-198 More About Use Cases  Generalization and Actors  Generalization and Use Cases  The Use of Include

9. Distributed Java Programming 107-198 Generalization and Actors

10. Distributed Java Programming 107-198 Generalization and Actors  Generalization allows us to capture roles that share responsibilities.  Using generalization when modeling the actors in your system allows you to easily define security roles for each user.  Do not try to jam too many actor generalizations on one screen. It makes things difficult to read and understand.

11. Distributed Java Programming 107-198 Generalization and Use Cases

12. Distributed Java Programming 107-198 Generalization and Use Cases  Sometimes one process will build on the functionality of another process.  The generalization in a use case is very similar to an inheritance hierarchy in a class diagram.  In our example previously, the generalization shown between “Deposit Check” and “Deposit Payment” are very similar. “Deposit Check” puts the money into your bank account. “Deposit Payment” puts the money against a liability owed to the bank.

13. Distributed Java Programming 107-198 The Include Statement

14. Distributed Java Programming 107-198 The Include Statement  The include statement allows you to indicate that the functionality provided in one use case is used in another use case.  It is a time saving measure. Particularly when you have to translate your use case diagrams into use case specifications.

15. Distributed Java Programming 107-198 Use Case Specification  More rigorous definition of a specific use case.  Defines the pre and post conditions for a use case.  Defines any exceptions that can occur and how they must be handled.  Defines each of the individual steps involved within the user case.  See the hand out for an example use case specification.

16. Distributed Java Programming 107-198 Closing Thoughts……  Use case diagrams are useful tools for communicating with business users about the development team’s understanding of a set of processes.  Keep your use case diagrams simple. Use cases decompose complex processes in easy to understand pieces.  Use case specification documents are what the development team will be working off of when they begin coding.  The definitions for a use case specification must be rigorous.  If your use cases are designed properly, they should represent one discrete piece of functionality on a project plan.

17. Distributed Java Programming 107-198 Assignment 1  Take an existing business process at your work (Or make one up)  Build a use case diagram demonstrating how 1 or more roles perform various use cases. Proper notation is required and the process you pick must have 3 – 4 use cases in it.  Take one use case and write a full user specification.  Based upon your use case, build a class diagram.  Show all classes derived from the use case  Show their properties, methods and access levels.  Show multiplicity and any inheritance relationships that may exist between.

18. Distributed Java Programming 107-198 Resources Martin Fowler UML Distilled Second Edition Safari-informit.com Poseidon UML www.gentleware.com UML Resource Center www.rational.com/uml