Exit Transition Guards and Activity Invariants Must Form a Complete Set.For example, guards such as x 0 are not complete because it isn’t clear what happens when x is 0. Guards on Decision Points Must Form a Complete Set.For example guards such as x 0 are consistent whereas guard such as x = 0 are not consistent because they overlap – it isn’t clear what should happen when x is 0. Each Transition Leaving a Decision Point Must Have a Guard.The Fill Out Enrollment Forms activity in Figure 1Ī guard is a condition that must be true in order to traverse a transition. The guards, depicted using the format, on the transitions leaving the decision point also help to describe the decision point. In Figure 1 you see that there is no label on the decision point, unlike traditional flowcharts which would include text describing the actual decision being made, you need to imply that the decision concerns whether the person was enrolled in the university based on the activity that the decision point follows. Decision Points Should Reflect the Previous Activity.A miracle activity is one that has transitions out of it but none into it, something that should be true only of start points.Ī decision point is modeled as a diamond on a UML Activity diagram. A black hole activity is one that has transitions into it but none out, typically indicating that you have either missed one or more transitions. A good rule of thumb is that if an operation is so complex you need to develop a UML Activity diagram to understand it that you should consider refactoring it.Īn activity, also known as an activity state, on a UML Activity diagram typically represents the invocation of an operation, a step in a business process, or an entire business process. Flowcharting Operations Implies the Need to Simplify.Figure 2 is interesting because it does not include an end point because it describes a continuous process – sometimes the guidelines don’t apply. An ending point is modeled with a filled in circle with a border around it, using the same notation that UML State Chart diagrams use. Figure 1, which models the business process of enrolling in a university, takes this approach. Every UML Activity Diagram should have a starting point, and placing it in the top-left corner reflects the way that people in Western cultures begin reading. A start point is modeled with a filled in circle, using the same notation that UML State Chart diagrams use. Place The Start Point In The Top-Left Corner.Modeling a business process with a UML Activity Diagram. They are used to explore the logic of:įigure 1. In many ways UML Activity diagrams are the object-oriented equivalent of flow charts and data-flow diagrams (DFDs).
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |