1. Analysis Classes

3. What Is an Analysis Class?  A class that represents initial data and behavior requirements, and whose software and hardware-oriented details have not been specified  Analysis class diagram – a UML diagram showing analysis classes and their relationships

4. Stereotypes of Analysis Classes Entity Class Purpose: Hold data Mostly corresponds to conceptual data model classes Boundary Class Purpose: Used by Actors or another system for interaction Control Class Purpose: Coordinates tasks and captures main application logic in a use case

6. What Is a Sequence Diagram?  A UML diagram that shows the interaction between objects to perform critical pieces of use case behavior in a time-ordered manner  Interactions are in the form of messages  Behavioral responsibilities are assigned to message recipients

7. Drawing a Sequence Diagram?  Employ use case diagram to determine use cases  Determine actors that interact with the use case  Consider one use case at a time (using text- based, detailed descriptions)  For a given use case, specify a boundary class between the use case and each actor (if there are 2 actors  2 boundary classes)  For a given use case, specify one control class  Derive entity classes from object relations for use case

9. Symbols in a Sequence Diagram  Box or class stereotype symbol represents objects.  Dotted vertical line represents object’s lifetime.  Thin bars represent focus of control, periods of time when object is behaving (fulfilling responsibilities).  Labeled horizontal lines represent messages passing between objects.

11. Typically, actors interact with boundary classes, which in turn interact with control classes, which in turn interact with entity classes. (pg. 265)

12. Reading a Sequence Diagram The actor :Customer invokes the use case by selecting one or more items. The message //select item is conveyed to :OrderForm. The form passes the message to control object :OrderControl From here an order is created and line items are added :Order creates a new order :LineItem adds new line items

13. Actors can talk only to boundary objects Boundary objects can talk to controllers and actors Entity objects also can talk only to controllers Controllers can talk to other controllers

14. Analysis Class Diagrams Similar to class diagrams EXCEPT: Includes boundary and control classes Operations (behaviors) are depicted in the lower third of a class box. Operations fulfill the class’s responsibilities.

15. What Is an Activity Diagram?  A diagram that emphasizes the flow of control from activity to activity in an object  Similar to the traditional program flowchart  Used to provide detail for complex algorithms

16. Elements of Activity Diagrams  Activity – a behavior that an object carries out while in a particular state  Transition – a movement from one activity or state to another  Decision point – a diamond symbol containing a condition whose results provide transitions to different paths of activities  Synchronization bar – horizontal or vertical bars denoting parallel or concurrent paths of activities

17. Activity diagram with a decision point One of the two possible paths will be selected for each execution

18. Activity diagram with synchronization bars Top synchronization bar is a fork. Bottom synchronization bar is a join.

19. What Is a Business Rule?  A directive that is intended to influence or guide business behavior in support of business policy formulated in response to an opportunity or threat  In information systems, business rules are implemented as data, constraints, and/or program code.

20. Types of Business Rules  Constraints – restrictions, mainly in the form of permissible values, validation rules, and multiplicities  Calculations – mathematical formulas or algorithms that produce some value  Value inferences – decision tables that result in attribute values being set  Action enablers – decision tables that result in actions being taken

21. Constraints  Permissable Values Exam score <= 100  Permissable Values  Exam score <= 100  Validation Rules  Referential Integrity – whereby the value of Salesperson in SALES1 class must hold same value as that of Salesperson in the SALESPERSON class.  Multiplicity Constraints  A student can enroll in no more than 5 courses a semester (0..5)

22. Calculations  Derived Values  Calculating tax as a percentage of sales or federal payroll tax deduction  Simple calculations are stored as a method attached to an attribute in the entity class  Complex algoritms or calculated values  Entails complex logic  Can change over time  Best stored in a control class since its best to keep volatile elements away from entity classes

23. Any Questions?