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Messages - Paul Lotz

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Bugs and Issues / Re: activity on act. diagram not under diagram in
« on: May 15, 2008, 09:06:28 am »
Here is another problem (I was afraid of this) that occurs with the subactivity link method.  If I drag an activity (paste as simple link) onto the activity diagram for the host activity and drag it onto the activity element for the host activity, then the subactivity moves below the host activity in the project (which seems proper).  Now often this is what I want, but it is not desired if the subactivity is used in multiple places (which happens, for instance, if I have factored out common behavior from a high-level use case, which is good design).

The alternative is to opt to paste the activity as an invocation of the activity (Action) which is where we were before.  At this point I would expect that we would be able to show any embedded elements (esp. activity parameters) in the invoked activity as action pins on the action, but unfortunately this is not the case.  Moreover, the action should be linked to the invoked activity, but it is not.  So we are back to the same basic issues.

Bugs and Issues / Re: activity on act. diagram not under diagram in
« on: May 15, 2008, 08:00:54 am »

In practice using subactivities on an activity diagram in EA as you suggest seems to offer a number of advantages (maintenance of hierarchy, as well as ease of using embedded activity parameters).  So thanks!

What makes me nervous is:
1) From what I can tell (and I haven't found a great definition, but what I glean from the UML spec. and other sources follows) actions should work as subactivities currently do.  In other words, we should be using actions instead of subactivities (except where I noted in my previous message) and the actions should provide the same hierarchical and object flow advantages currently sported by subactivities.  I suggest the action behavior is incorrect and EA will want to fix this.
2) I don't think it is possible to convert an action to an activity or vice versa in EA, so it would be painful to start with one and then switch to the other after the fact.
3) The hierarchy is maintained well using subactivities but I wonder if pasting a linked copy of a subactivity on its subdiagram and then adding parts to it is semantically correct (I don't know the answer to this one--the inserted parts have no semantic link to the pasted link, but I suppose the pasted link functions much like a diagram frame--otherwise missing from EA, would function), although it certainly does the trick graphically.

Anyway, despite my misgivings, this seems to be the best approach currently available in EA and I will try working with it.  Thanks for your advice!


Bugs and Issues / Re: activity on act. diagram not under diagram in
« on: May 15, 2008, 02:18:14 am »
Why did you create an instance "Action1" of the EditConfiguration activity?

What I do in such cases is this:

1. Make the EditConfiguration activity composite.
2. Into the EditConfiguration diagram which is then created, drag the EditConfiguration activity (as simple link, not as instance).
3. Resize the EditConfiguration activity in the child diagram so that it fills most of the page (leavig space for common objects and activities to be placed outside and called from inside it).
4. Draw new ConfigureSubsystem1 a.s.o activities inside the EditConfiguration activity on the child diagram.

This should lead to the hierarchy in the project browser that you want.

Thanks, Frank.  The distinction I am trying to make is that I am detailing an action, not an activity, via an activity diagram.  This should be legal (and more proper!) in UML but EA doesn't maintain the hierarchy as I would expect.

[I am finding the distinction between activity and action in UML to be not all that meaningful.  My interpretation is that an activity should generally be composed of actions, which in turn can be detailed in further activity diagrams.  An activity diagram may have activities on it when we detail a complex structure containing multiple actions--rather than putting it in a subdiagram, but anything "atomic" on the current diagram should be an action.  (An action isn't necessarily really atomic since it can be broken down with arbitrary complexity on a separate diagram).  If there is a more accurate interpretation I'd love to hear it.]

Bugs and Issues / Re: activity on act. diagram not under diagram in
« on: May 14, 2008, 10:02:56 am »
I read that in the specification.  I see that I do need to change the action to call behavior, but I don't see how it helps resolve the particular issue, though.  Not sure if it's me.

Let me give an example.  (I wish I could post a project file, but I will include some images instead.)

Suppose we want to indicate how we would do configuration using object flow.  Then we might set up a ConfigureSystem Activity like so:
We need to further define what happens in the EditConfiguration action, which we can do thus: .
In practice I chose to made the original EditConfiguration action composite, which created a new activity diagram under the EditConfiguration action, but when I added an EditConfiguration activity to the EditConfiguration activity diagram, the EditConfiguration activity was not associated with the diagram but appeared in the package root: .
At least double-clicking on the EditConfiguration action does bring up the EditConfiguration activity diagram.
I tried creating a new action that was a call behavior linked to the EditBehavior activity (behavioral classifier).  This may be correct, but I still see problems here: 1) There is no hierarchy in the project for activitiees; 2) double-clicking on the new action does not bring up the EditConfiguration activity diagram--although I presume I could force it to do so by making it composite and moving the diagram, and 3) most importantly, the EditConfiguration activity still has no connection to the activity diagram on which it resides in the project.  I think the last is the biggest issue.  Why can't the EditConfiguration activity reside with the EditConfiguration diagram in the project?

Place an action on an activity diagram.  Make the action complex so that EA creates a new activity diagram (for detailing the action) beneath the action in the project hierarchy.  On this new diagram add an activity (common in the case in which we want to show object flow).  The new activity does not appear associated with the diagram in the project.  (Instead, it appears at the root level for the package.)  I think this is a bug.  (If we use activities instead of actions this is not the case, by the way, but I think it is more correct to use actions.)

Uml Process / Re: Triggers, type: change, tutorials ?
« on: May 09, 2014, 02:58:54 am »
An example of a ChangeEvent is, for motion on an axis, the move completes (so, inPositionIsTrue=T, or movingIsTrue=F, or some other similar attribute).  (Prior to the event, of course, the values of these attributes were different.)

In a state machine model, you can add a transition between two states, define the transition Type as Change, define a specification for the trigger (in v 10.0.1009--I don't remember being able to do this before), and save this newly defined trigger.

I don't see a way to show the specification on the diagram, unfortunately.  (We found it more expressive in the past to define a transition with only a guard instead (e.g., [inPositionIsTrue=T], in order to distinguish visually between SignalEvents and ChangeEvents.  This was OK for us since we weren't trying to generate code, but a ChangeEvent is more proper UML.  It is legal to name the ChangeEvent inPositionIsTrue=T, but there may be a better way to express that.  I'd like to hear some ideas on this.)


Uml Process / Re: State Machines, entry/exit actions and classes
« on: August 31, 2012, 02:53:05 am »
It's not entirely clear to me what you are doing, so I may repeat a bit of what you are actually doing.

For something like this we implement the state machine using the State Pattern.  For this we have a Context class (I think this would be your Class) and then states that we implement as state classes.  This means that each state class can define its own entry and exit methods [(e.g., Enabled:entry()].  Each method on a state class can invoke one or more methods on the Context* to carry out specific (atomic) tasks, in any desired arrangment.

*We actually break the Context class of the classic State Pattern into two pieces, Context and Model.  Context provides an interface to clients and contains a Model object.  Model provides an interface to the State methods.

Uml Process / Re: Newbie UML question: configuration parameters?
« on: June 29, 2011, 04:04:14 am »
Oh, and the classes that use a configuration have an attribute for that configuration.

Uml Process / Re: Newbie UML question: configuration parameters?
« on: June 29, 2011, 04:01:25 am »
Well, one can show files as artifacts in a deployment diagram.

What we do:
On our statemachine diagrams I make a note that we read initialization files on a transition between two specific states.
We don't show the files directly, but we include descriptions of the data structures in the configuration files as classes (well, in our case we are modeling something that isn't exactly a class, but that's not important here) in the model.

Uml Process / Re: Newbie UML question: configuration parameters?
« on: June 24, 2011, 02:43:02 am »
Do you want to model the configuration file data, the initialization behavior, or both?

Uml Process / Re: Use-case extension points
« on: November 05, 2010, 08:03:18 am »
Ah!  That helps!  Now I understand what you want.  (I didn't know about these.)

I see how to create the extension points in EA (, but you already know this.

The only thing I can see to do is add a constraint to the extend relationship.  It will then show on the diagram, so the appearance will be similar to the example you gave, but the designer has to type in the extension point.  He can't select it from a list; the relationship is informal.  I don't know of a way to do this more formally.  Yes, it would be good if there was a way!

Uml Process / Re: Use-case extension points
« on: November 05, 2010, 05:30:34 am »
I'm not quite sure what you mean, actually.  There is an "extend" relationship connector in the Use Case toolbox.

Do you mean you want to add a text description to the relationship?

Each relationship has a note compartment, but I don't you can show that on the diagram (although I expect you can show this in an RTF report).  If you want to show the text on a diagram your best bet is to add a Note element to the diagram and link it to one of the elements.

Or are you asking something different?

Uml Process / Re: Triggers, Events and Signals
« on: October 06, 2010, 03:14:41 am »
This could all make perfect sense if Signal had attributes.

One small point: a Signal can indeed have attributes.

Uml Process / Re: Linking sequence diagram to Use Case
« on: August 11, 2010, 02:18:18 am »
Once you create the link you can fix the model up a bit so that it reflects the hierarchy exactly the way you want.

Uml Process / Re: Linking sequence diagram to Use Case
« on: August 11, 2010, 02:12:42 am »
Yes, you can drag the diagram under the use case, then right-click on the use case and select Advanced...Make Composite from the pop-up menu.  If the sequence diagram is the only diagram under the use case (and it wasn't already a composite) then this will link the two so that if you subsequently double click on the use case it will open the sequence diagram.

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