Software Engineering I
Oct. 30, 2012 Notes

Modeling interactions and behavior

  - Modeling system dynamics
  - Looking at two different types of interaction
    + Diagrams used to model detailed scenarios of system execution
      - UML Sequence Diagrams
      - UML Communication Diagrams
    + Diagrams used to model system behavior
      - UML State Diagrams
      - UML Activity Diagrams

What are Interaction Diagrams?

  - Used to model dynamic aspects of a system
  - To see how it runs
  - Includes instances of classes or actors and messages shown as arrows
    + Messages are from actor to object or from object to object
  - Helps to understand the sequence of messages

Sequence diagrams
  - messages exchanged by sets of objects and possibly actors for a given task

  - Objects are arranged from left to right

  - Actor initiates interaction on the left

  - Start at the top of the diagram

  - Time progresses downward

  - Lifeline - Vertical dashed lines relate the object to its progression of
               actions over time.
             - Connects object to activation box

  - Activation Box - small box attached to lifeline indicating the time during
    which computations are performed.

Example Class Diagram

  +-------------------+       +-----------------------+       +------------+
  | Course            | 1   * | CourseSection         | 1   * |Registration|
  +-------------------+-------+-----------------------+-------+------------+
  | getPrerequisite() |       | requestToRegister()   |             | *
  +-------------------+       |addToRegistrationList()|             |
                              +-----------------------+             | 1
                                                          +-----------------+
                                                          | Student         |
                                                          +-----------------+
                                                          |addToSchedule()  |
                                                          |hasPassedCourse()|
                                                          +-----------------+

Example Sequence Diagram

   O
  -+-               +----------------+                          +----------+
   |                | :CourseSection |                          | :Student |
  / \               | -------------- |                          | -------- |
                    +----------------+                          +----------+
   | requestToRegister    |   create     +---------------+            |
  +-+ - - - - - - - - |> +-+ - - - - - |>| :Registration |            
  | |                    | |             | ------------- |            |
  | |                    | |             +---------------+           +-+
  | |                    | |                       |  |- - - - - - |>| |
  | |                    | | addToRegistrationList |  | addToSchedule| |
  | |                    | |<| - - - - - - - - - - |  |              | |
  +-+                    +-+                       +--+              +-+
   |                      |                         |                 |

   |                      |                         |                 |