How to draw a UML activity diagram

The UML activity diagram records the logic of a single operation or method, a single user case, or a single business flow. To create a UML activity diagram, you must perform the following steps repeatedly to modify the sixth chapter of the object entry level 2.

Step 1: define the range of the activity diagram

First, define what modeling you want. Individual user case? Part of a user case? A business process that contains multiple user cases? A single method of a class? Once you define the scope of your drawing, you should add a label at the top of the graph to indicate the title and unique identifier of the graph. You may also want to include the time of the graph or the author name.

 

Step 2: add the start and end points

Each activity chart has a start point and end point, so you must add them immediately. InUML Distilled)(See references), Fowler and Scott think that the end point is optional. Sometimes an activity is just a simple end. In this case, it is harmless to indicate that the only change is to an end point. As a result, when someone else reads your chart, he or she knows that you have considered how to exit these activities.

 

Step 3: add an activity

If you are modeling a User case, introduce an activity to the main steps that each role (actor) sends (this activity may include the start step, add any steps for the system response to the start step ). If you are modeling a high-level business process, introduce an activity for each major process, typically a User case or user case package. Finally, if you are modeling a method, it is common to introduce this activity.

 

Step 4: Add transition between activities

My style should always exit an activity, even if it is switched to an end point. Once there are multiple transformations in an activity, you must mark each transformation accordingly.

 

Step 5: Add a decision point

Sometimes, the logic you model requires a decision. Some transactions may need to be checked or compared. Note that the use of decision points is optional. For example, in Figure 1, I can simply transfer the "accept" and "reject" transformations directly to the "enrollin University" activity. "

 

Step 6: Find out parallel activities

When there is no direct connection between two activities and they must all end before the start of the third activity, they can run in parallel. In Figure 1, you can see that "attendoverview" and "enroll in seminars" may be performed in any order, however, they must be completed before you complete the entire process.

Figure 1. UML activity diagram for first registration at school