Design and Usecase Realization Software Engineering Laboratory Fall

Design and Use-case Realization Software Engineering Laboratory Fall 2006 Sharif University of Technology 1

Outline n UML related issues. ¡ ¡ n Use-case Realization. ¡ n n Class Diagram. Interaction Diagrams. Use-Case Realization Report. An Example (Login) SEPID - Design Sharif University of Technology 2

UML related issues n Class Diagram: ¡ n The diagrams describing the classes and relationships that participate in the realization of the use case. Interaction Diagrams: ¡ The diagrams (sequence and collaboration diagrams) describing how the use case is realized in terms of collaborating objects. Sharif University of Technology 3

Class Diagrams n n A class diagram describes the types of objects in the system and the various kinds of relationships that exist among them. Class diagrams also show the attributes and operations of a class and the constraints that apply to the way objects are connected. Sharif University of Technology 4

Classes in UML Sharif University of Technology 5

Relationships (Dependency) n n A dependency is a using relationship that states that a change in specification of one thing may affect another thing that uses it, but not necessarily the reverse. Some source of dependency: ¡ ¡ ¡ Using methods of other class Using other class as argument of methods Throwing exception Sharif University of Technology 6

Relationships (Generalization) n n one thing is-a-kind-of a more general thing. Generalization at the implementation perspective is associated with inheritance in programming languages. Sharif University of Technology 7

Relationships (Association ) n n n An association is a structural relationship that specifies that objects of one thing are connected to objects of another. Association can have Multiplicity Types of association: ¡ ¡ Aggregation Composition Sharif University of Technology 8

Aggregation and Composition n n Aggregation is the part-of relationship. but the part object can exists alone. composition is also part of relationship, but the part object may belong to only one whole Sharif University of Technology 9

Interaction Diagrams n n n Types of interaction diagrams: Sequence diagrams and collaboration diagrams. Sequence diagrams show the explicit sequence of messages and are better when it is important to visualize the time ordering of messages. Collaboration diagrams show the communication links between objects and are better for understanding all of the effects on a given object and for algorithm design. Sharif University of Technology 10

Sequence Diagram Sharif University of Technology 11

Collaboration Diagram Sharif University of Technology 12

Use-case Realization n n represents the design perspective of a use case. A use-case realization describes how a particular use case is realized within the design model, in terms of collaborating objects. Sharif University of Technology 13

Some Points n n Use case realization typically has two parts: ¡ express the structure of the use case ¡ express the behavior of the use case. In other words it shows the flow of events in a use case A use-case can be realized in different ways The use-case realization completely realizes the selected sub-flows of the use case; there is no missing behavior. All required behavior has been unambiguously distributed among the model elements participating in the use-case realization. Sharif University of Technology 14

Some Points (cont. ) n n The Flow of Events Design should be readable and suit its purpose. The diagrams describing the use-case realization should be readable and suit their purpose. Where several diagrams illustrate the usecase realization, the role of each is clear, and the diagrams are consistent with one another. All exceptional cases to be considered in the current iteration have been handled. Sharif University of Technology 15

Use-Case Realization Report n Brief Description ¡ n Flow of Events Design ¡ n Objects participating in interaction diagrams of the use-case realization. For each object, its class and brief description. Class Diagrams ¡ n Interaction Diagrams of the use-case realization. Participating Objects ¡ n A Flow of Events Design of the use-case realization. Interaction Diagrams ¡ n A Brief Description of the realized use case. Class Diagrams of the use-case realization. Derived Requirements ¡ Derived Requirements of the use-case realization. Sharif University of Technology 16

An Example (Login) n n n Consider we want to realize login use-case of a system. Login: User can enter to system after entering its username and password correctly. At first we try to specify the structure of Login Use-case. Sharif University of Technology 17