Sequence diagram limitations

[ChrisWhite]

Dear Forum,

I have noticed the following behaviour when constructing a sequence diagram. If I create a lifeline and then try to select a UML device as an instance classifier I am unable to see that device in the selection window (ctrl-L method). This would be the correct behaviour IF devices were not instantiable. However, the OMG intended them to be instantiable and there are examples in the UML Superstructures document to show this  (see devices from nodes).

Further, I have discovered that if I introduce the device into my sequence diagram by drop-and-drag it will create a new instance of that device (correctly as I see it). This seems to be inconsistent.

The question is why am I unable to instantiate a device for my sequence diagram using the lifeline context menu and select instance classifier?

many regards,

[qwerty]

I have no trouble seeing a node in the selection window after ctrl-L. What version are you using? (I just tried with 9.3)

Whether a new instance is created depends on your settings. Try to ctrl-drag the node to get the options window.

q.

[ChrisWhite]

Hi q,
Hi All,

yes, I can drag the device into the sequence diagram and then select "an instance of" but the device then appears as an device instance in the project browser instead of a lifeline symbol with the instance classifier set as a device.

You could argue that this is also correct - an instance has been created. However, in the project browser this instance does not appear as the lifeline icon, it appears as a device icon. For a model reader that is not so experienced with EA this is somewhat confusing (all other instances can be achieved with the lifeline symbol which is then uniform to the sequence diagram itself).  

Interesting, that you can see the device using ctl-L; I can only see devices which are complex (have sub-devices).

We are presently using 9.3 here but intending to migrate to 10 soon.

Thanks for your commments q,
Chris

[qwerty]

Actually there is a difference between ctrl-drag and using ctrl-L. Creating a lifeline first and then using ctrl-L results in a lifeline element in the project browser. When ctrl-dragging the node you get a node instance. I'd say this is typical EAUI. Probably all elements instantiated on a sequence diagram should result in a lifeline. On other diagrams they should be converted to object instances. You might report that as a bug...

Regarding the "hidden" nodes in your model: please try with a blank repository. It might be connected with inconsistencies in the model itself (also try running a consistency check). Another reason might be some MDG or add-in.

q.

[ChrisWhite]

Thanks q, for this.
Regarding the sequence diagram lifelines; this was also my train of thought.

Regarding the hidden elements; I will check this as you suggest. The strange thing is, as soon as the device is made a compound element, it becomes visible. Very strange.

Thanks for the tips.
Regards,