R include relation an include relation from one use

This preview shows page 84 - 87 out of 182 pages.

r Include relation: An include relation from one use case to another use case depicts that the interaction sequence of the first use case includes the interaction sequence of the other use case. Objects System boundary Communication between actor and use case Use Case 23 [name] Use Case B Use Case A «extend» Use Case A Use Case B «include» Relations [name] [name] Actor (person) Actor (alternative notation) [name] Use case extend include «actor» [name] «system» [Name] Actor (system) X s o p q r
Image of page 84

Subscribe to view the full document.

66 6 Model-Based Requirements Documentation s Relation between actors and use cases: If communication between a use case and one or more actors takes place during the execution of the use case, the communication must be annotated by means of a communication relation between the respective actors and the use case. Example of UML Use Case Diagrams Figure 6-4 shows an example of a use case diagram. Figure 6-4 An example using modeling elements of use case diagrams The model comprises the use cases “download traffic information”, “retrieve current position”, and “input navigate to destination” elements. The relations in figure 6-4 that are labeled by numbers are explained in further detail below: Include n The use case “navigate to destination” is related to the use cases “input destination” and “retrieve current position” via an include relation. The relationship depicts that the interaction steps defined in the use cases “input destination” and “retrieve current position” are contained in the use case “navigate to destination”. Extend o The extend relation between the use cases “download traffic information” and “navigate to destination” defines that the interaction steps defined in the use case “download traffic information” are included in the interaction steps of the use case X o X
Image of page 85
6.3 Use Cases 67 “navigate to destination” if a certain condition, such as “avoid congestion”, is met. The extension point “avoid congestion” depicts the step in the use case “navigate to destination” at which the additional interaction steps are being executed. Generalization UML also provides a generalization relation between use cases or actors. In this case, the specializing use cases or actors inherit the properties of the generalizing use case or actor (e.g., [Rumbaugh et al. 2005] ). For instance, the actors “service mechanic” and “customer service representative” can be generalized as the actor “employee”. The generalizing actor would carry all aspects that the actors “service mechanic” and “customer service repre- sentative” have in common (e.g., employee ID). 6.3.2 Use Case Specifications Use case diagrams show the system’s relevant functions from a user’s per- spective and specific relationships between the functions of the system or between functions of the system and aspects in the system’s context. With the exception of a use case’s name and its relationships, use cases diagrams
Image of page 86

Subscribe to view the full document.

Image of page 87

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern

Ask Expert Tutors You can ask 0 bonus questions You can ask 0 questions (0 expire soon) You can ask 0 questions (will expire )
Answers in as fast as 15 minutes