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What is the use is of include and extends relationships in use case diagram?
“The include relationship is intended for reusing behaviour modeled by another use case, whereas the extend relationship is intended for adding parts to existing use cases as well as for modeling optional system services” (Overgaard and Palmkvist, Use Cases: Patterns and Blueprints.
What is include relationship in use case diagram?
In UML modeling, an include relationship is a relationship in which one use case (the base use case) includes the functionality of another use case (the inclusion use case). The include relationship supports the reuse of functionality in a use-case model.
What does extend means in use case diagram?
Extend is a directed relationship that specifies how and when the behavior defined in usually supplementary (optional) extending use case can be inserted into the behavior defined in the extended use case. The extension takes place at one or more extension points defined in the extended use case.
How to explain relationships in use case diagrams?
When it comes to drawing use case diagrams one area many struggles with is showing various relationships in use case diagrams. In fact many tend to confuse < >, < > and generalization. This article will look into various use case diagram relationships in detail and explain them using examples.
How to include and extend use case relationships?
Here’s a correct approach (in my view, and checked against Jacobson, Fowler, Larmen and 10 other references). The key to Include and extend use case relationships is to realize that, common with the rest of UML, the dotted arrow between use cases is a dependency relationship.
What’s the difference between include and extend relationships?
“The include relationship is intended for reusing behaviour modeled by another use case, whereas the extend relationship is intended for adding parts to existing use cases as well as for modeling optional system services” (Overgaard and Palmkvist, Use Cases: Patterns and Blueprints.
When to use include and extend in use?
The included use case cannot stand alone and the original use case is not complete without the included one. This should be used sparingly and only in cases where the duplication is significant and exists by design (rather than by coincidence).