Subject: Object Oriented Modeling and Design

Difficulty: Medium

Marks: 4 Marks

<<include>> relationships: Include relationship is used to include one use case within the behavior sequence of another use case.

• An include relationship between use cases means that the base case explicitly incorporates the behavior of another use case at a location specified in the base.
• The include use case never stand alone. When an actor initiates any base use case then base use case executes included use case.
• An include relationship as a dependency can be render with stereotyped as include. To specify the location in a flow of events in which the base use case includes the behavior of another, write include followed by the name of the use case.
• Arrow is placed near the included use case. Arrow is directed from base use case to included use case.

Example:

<<extend>> relationships: It adds incremental behavior of an use case.

• A extend relationship between use cases means that the base use case implicitly incorporates the behavior of another use case at a location specified indirectly by the extending use case.
• The extended use case adds itself to the base use case. Most of the time, an extend relationship has a condition attached to it. The extended use case executes only when the condition is true.
• The base use case may stand alone, but under certain conditions, its behavior may be extended by behavior of another use case.
• An extend relationship as a dependency can be render with stereotyped as extend. Arrow is directed from extended use case towards base use case.

Example: