There are several ways you can customize your chart: add a color scheme, change the font, or add notes. Now you should have a simple use case diagram. ![]() Drag lines from the actors to the use cases by pulling out a line from the red dots that appear when you hover over the shape. For instance, if your check-in app does not support taking photos, but it's on the agenda for a future release, put it outside the system. Place each use case in the system that supports it, and draw use cases not supported by your system outside the box. Start with major activities or transactions, leaving sub-activities for later. Possible use cases would be checking in, searching for a nearby venue, and finding friends. For example, if you're developing a check-in mobile application, the system would be the app, and the actor would be the user. A relationship from an extending use case to an extended use case that specifies how. These ovals represent the activities that actors will perform with the help of your system. Now it's time to drag use cases onto your system. ![]() Rename your actors to reflect their role. Actors are represented by stick figures, a fitting symbol since actors are often people. Your use case diagram should reflect the actor's perspective, so ask yourself what the end user wants from the system. In a development use case, systems represent what you are developing, such as a software component or a complete suite. In Lucidchart, this shape is labeled as a rectangle container. Writing Effective Use Cases ( amazon US).Begin by dragging a system boundary box onto your canvas. If you have to expend any effort on use cases (instead of User Stories) you should focus on the text-based use cases:Īlistair Cockburn: Structuring use cases with goals For the most part, the popular text books on UML introduce the include relationship but give little useful guidance on the extend and the generalisation relationships. With the exception of the system boundary diagram, which I�ll describe in a minute, I recommend that you avoid the them entirely. UML defines three stereotypes of association between Use Cases, include, extend and generalisation. Of all the diagrams in UML, use case diagrams are the most confusing, and the least useful. UML for Java� Programmers ( amazon US) p.66: Defining the relationship between two use cases is the decision of the software analysts of the use case diagram. ![]() Then there is also the "include" which typically is a fragment can be shared between multiple use cases.įrankly, use case diagrams are of limited usefulness � they just serve as an overall map of your use cases. The base case can specify multiple extension point names - the extension can then insert segments into these extension point to modify the behavior of the base case. When do I use the extends arrow What is the difference between uses and extends The scenario I want to describe branches into several possible outcomes, or has some error conditions. So to get the full extended use case you have to look at "base + extend". Each child is a full description of a use case.Īn extend is more like a "plugin" or "module" that plugs into the extension points of the base use case. The parent captures the commonality of the children - the parent could be abstract. The generalization is "more like" inheritance. Should have looked at the diagram to get those neurons firing again.
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