Checking UML Sequence Diagrams
Table of contents
With Model Expert you can validate UML Sequence diagrams to check for some common errors:
- Lifelines not being instances of EA types
- Messages between lifelines not calling methods of the target
Note: Sequence diagrams are checked against a fixed set of rules, and do not use a reference model.
Example
| Step | Description | See Also |
|---|---|---|
| Find the package ‘Example 2 – Sequence diagrams’, and open the ‘Components’ diagram: | 
These are some simple components, with some simple operations. |
|
| Find the sequence diagram ‘Diagram #1’. | 
Note that Component 3 is not an instance of the component, it’s the component element itself – a deliberate mistake. If you switch on the diagram setting ‘Show Namespace’ then EA makes it more obvious that you’ve made a mistake..) |
|
Now create some messages between the components
|
This is the best way to avoid mistakes, but it only works if you know the EA trick of choosing valid operations from the drop-down. But EA will let you make a message using anything: | |
| Now create another message, but this time just type in a new name for the message:
|
This message doesn’t exist as an operation on the target component, so is probably an error.
The resulting sequence diagram now has two errors:
|
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| Right-click on the diagram, and choose Specialize/Model Expert/Check sequence diagram | This produces a list of the errors in the diagram:
…and will add colors to the diagram, to show where the errors are:
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| You can now see where to correct the errors in the diagram, using standard EA functions. |
