7/23/2023 0 Comments Activity diagrams visioThese indicate the “state” of the person being woken up. In the example above there are three states, Asleep, Sleepy and Awake. As far as I can tell, there’s no difference.) States are used to indicate milestones in processing of your activity diagrams. (Sometimes they are segmented like in the examples above, sometimes they’re not. States are represented by rounded rectangles. (Frankly, no one seems to use the same conventions in UML diagrams anyhow, so you could probably use pink elephants to indicate decision points, so long as you’re consistent!) States In general, the decision to use Decision Points is up to you. Here’s the car buying diagram again, this time without the transition point: You can also simply draw multiple guarded transitions out of an activity. You don’t need to use decision points to show decisions. For instance, it wouldn’t make since in the diagram above to show that if we have more than $100 that we’ll buy a sensible car, because that could overlap with Too Much Money guard and we wouldn’t know what to do. And, if we happen to have too much money we’re going to end up with a nice sports car. However, as long as we don’t have too much money we’re going to be able to drive a Sensible Car. We can see that if we’ve got less than a $100 we’re going to be stuck in a used Yugo. This rather simplified diagram illustrates the decisions involved in buying a car. For flow to progress through a guarded transition the guard must evaluate to true in the context of the decision point. The text shown in square brackets on transitions out of the decision points is called Guards. If Still Tired? is No then the flow transitions on to the Shut off Alarm and Get Out of Bed activities. The Get Out of Bed example uses a decision point “Still Tired?” If Still Tired? is Yes then the flow transitions to the Hit Snooze activity and then back to the Asleep state. There are two ways to draw logical branching in activity diagrams. There are nine transoms total in the example. In the Get Out of Bed example above, you can see that the Alarm Goes Off activity transitions to the Sleepy state. Transitions are used to indicate the process flow between elements in your diagram. The lines with open arrow heads are called Transitions. Activities are shaped like pills and have a description inside. In the previous example the activities were: Alarm Goes Off, Hit Snooze, Shut off Alarm and Get Out of Bed. This diagram is made up of the following notational elements: ActivitiesĪctivities are used to indicate actions which are preformed in your diagram. Here is an example Activity Diagram illustrating the Get Out of Bed use case: (In the ColdFusion world you really don’t need to worry about this difference.) The major difference is that activity diagrams allow for parallel processing of tasks. This is where Activity Diagrams come in.Īctivity Diagrams are very similar to standard flow charts. However, it doesn’t make any attempt to say anything about the steps involved. This Use Case diagram clearly states that Search Users will Search Content. For example, consider this Use Case diagram: Once you have gathered your Use Case diagrams you can continue on with the analysis phase by using Activity Diagrams.Īctivity Diagrams are used to illustrate the activities implicit in a use case. The Use Case diagram is a diagram used to gather requirements and help with analysis. In my last major entry on the UML I covered the Use Case diagram.
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