Reuse in Use-Case Models: >, >, and Inheritance
A model may have many use cases, so how do we organize the use cases that define what a system should do? And how do we use this information about use. Use case include is a directed relationship between two use cases which is used to show that behavior of the included use case (the addition) is inserted into the. In UML modeling, a relationship is a connection between two or more UML model elements Examples of relationships include associations, dependencies , model in several diagrams, including use-case, class, and component diagrams.
For example, other use cases may be inserted into the Project Selected extension point just described for the Manage Project use case. Such behavior sequences may include reviewing and updating project information, or selecting a specific version of a project before managing the details of the project in the succeeding behavior sequences.
Figure elaborates on the Administer System use case in Figure using extend dependencies. It shows that a system administrator is offered two options starting up the system or shutting down the system at the extension point named Administration Functions, which is described as being available on the administration menu of the user interface.
Figure further shows the following: Extension points and extend dependencies The Startup System use case is available as an option at the Administration Functions extension point of the Administer System use case.
The Startup System use case has two extension points named Before and After. The Before extension point is described as occurring before the startup functionality is performed by the system, and the After extension point is described as occurring after the startup functionality is performed by the system.
These extension points are used as follows: The Restore Data use case is available as an option at the Before extension point of the Startup System use case.
Before starting up the system, the system administrator may restore data from the backup system to the project management system's database that was previously archived. There are no options described for the After extension point of the Startup System use case.
The Shutdown System use case is available as an option at the Administration Functions extension point of the Administer System use case. The Shutdown System use case has two extension points, named Before and After. The Before extension point is described as occurring before the shutdown functionality is performed by the system, and the After extension point is described as occurring after the shutdown functionality is performed by the system.
The Backup Data use case is available as an option at the After extension point of the Shutdown System use case. After shutting down the system, the system administrator may back up data from the project management system's database to the backup system for later retrieval.
There are no options described for the Before extension point of the Shutdown System use case. The inheriting use case would completely replace one or more of the courses of action of the inherited use case.
In this case, the basic course of action is completely rewritten to reflect that new business rules are applied when the family member of a professor is enrolling at the university. Family members are allowed to enroll in the school, regardless of the marks they earned in high school, they don't have to pay any enrollment fees, and they are given top priority for enrollment in the university. Inheritance between use cases should be applied whenever a single condition, in this case, the student is a family member of a professor, would result in the definition of several alternate courses.
Without the option to define an inheriting use case, you need to introduce an alternate course to rework the check of the student's high-school marks, the charging of enrollment feeds, and for prioritization of who is allowed to enroll in the given semester. The inheriting use case is much simpler than the use case from which it inherits.
Use Case Diagram - UML 2 Diagrams - UML Modeling Tool
It should have a name, description, and identifier, and it should also indicate from which use case it inherits in the "Inherits From" section. This includes any section that is replaced, particularly the pre-conditions and post-conditions as well as any courses of action. If something is not replaced, then leave that section blank, assuming it is inherited from the parent use case you might want to put text, such as "see parent use case," in the section.
Inheritance Between Actors The fourth opportunity for indicating potential reuse within use-case models occurs between actors: An example of this is shown in Figure 1the "International Student" actor inherits from "Student. The standard UML notation for inheritance, the open-headed arrow, is used and the advice presented about the appropriate use of inheritance still applies: The DAD framework is a people-first, learning-oriented hybrid agile approach to IT solution delivery.
Types of relationships in UML modeling
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The supplier model element is independent because a change in the client does not affect it. The client model element depends on the supplier because a change to the supplier affects the client. Deploy A deploy relationship shows the specific component that an instance of a single node uses. In a UML model, a deploy relationship typically appears in deployment diagrams. Directed association A directed association relationship is an association that is navigable in only one direction and in which the control flows from one classifier to another for example, from an actor to a use case.
Only one of the association ends specifies navigability.
Extend An extend relationship between use cases indicates that one use case, the extended use case, can extend another use case, the base use case. An extend relationship has the option of using the extended use case. Generalization A generalization relationship indicates that a specialized child model element is based on a general parent model element.
Although the parent model element can have one or more children, and any child model element can have one or more parents, typically a single parent has multiple children. Generalization relationships appear in class, component, and use-case diagrams. Interface realization An interface realization relationship is a specialized type of implementation relationship between a classifier and a provided interface.