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Messages - Javier

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16
General Board / Re: Multiple instances of a class in a diagram
« on: November 09, 2004, 01:02:50 pm »
Thomas,

The reason for all these requests is two-fold:

- I'm diagramming the UML2 specification for learning purposes, working towards my second UML certification.  I just decided to begin with the Kernel::Root diagram and guess what?  The first thing I find is Element and Comment being associated multiple times.  Each class is actually twice in the diagram, and for good reason: clarity.

- I'm testing Enterprise Architect's UML2 compliance.  So far I've found a few glitches--for example, tree-style for a generalization relationship is present, but not for the aggregation relationship, perhaps because it's less common?

Needless to say, I need the classes to be in the same diagram  :(


Regards.

17
General Board / Re: Multiple instances of a class in a diagram
« on: November 09, 2004, 12:03:17 pm »
Bruno,

Thx for the reply, but I don't think it'll serve my purpose because it is an instance.  The reason I need this feature--hint, hint, available in Rational Rose--is that I'm modeling two classes with multiple associations (generalization and containment) between them and the diagram just gets cluttered.

A (cheesy) workaround I've found is to create another class with the same name and create the associations there.

Regards.

18
General Board / Multiple instances of a class in a diagram
« on: November 09, 2004, 09:00:03 am »
Is there a way to have more than one class instance of a class in a diagram?

My impression is that there isn't, but I'd like to confirm.  I am using version 4.10.732.

19
General Board / Re: Generalization (as a tree)
« on: November 09, 2004, 12:52:47 pm »
Thank you all.  Totally missed the Tree Style option...

20
General Board / Generalization (as a tree)
« on: November 09, 2004, 09:57:37 am »
Is there a way in EA to create a generalization and display it as a tree?

Say you have a parent class ClassA and two classes, ClassB and ClassC that derive from ClassA.

I want to display them with a generalization relationship as a tree instead of individual generalization relationships.

I'm using version 4.10.732

Regards.

21
General Board / Re: Assocition instead of Aggregation
« on: November 08, 2004, 11:53:10 pm »
TrTnJohn,

In the most generic terms, all associations can be represented with a dashed arrow and a stereotype.  Bidirectional associations with two dashed arrows, one on each direction

for example, generalization can be a dashed arrow and a <<specialize>> stereotype, composition can be a dashed arrow and a <<has a>> stereotype, etc.

Several of the associations are so common that they deserve their own icon, aggregation (hollow diamond) being one of them, and composition (filled diamond) being another.  Thus my comment on the "kind of" association.  You can think of composition as a kind of aggregation (explanation below).

Now, regarding your comments on aggregation and composition, it is important to note that aggregation (your "has a") has a lifetime implication.  An aggregated instance may have a different lifetime than the aggregating instance.

Composition, on the other hand (your "must have a") , implies that the aggregated and aggregating instances have the same lifetime.  Whan A goes away, B goes away.

Notice that the UML does not say whether A and B are associated during construction of the aggregating class or whether the association is built by calling a method in A after A is constructed.  This is in line with UML, since it takes care of the "logical" design aspect.  In C++ there is another aspect that it's called physical design (by John Lakos).

Lastly, I use generic associations in my designs.  For example, if I want to have a developer notice that A uses B in some way, just draw a dashed arrow pointing to B to note that A depends in some way on B (i.e., uses it in the class "interface", denoting that interface here means all the methods for A and B is used as a parameter in one of the methods).

Regards,

Javier



22
General Board / Re: Assocition instead of Aggregation
« on: November 03, 2004, 11:27:41 pm »
Phillipe,

You can consider an aggregation a "kind of" association that has semantics for the roles a class A and class B play.  When you forward-engineer the code, these semantics are unambigious and EA is capable of generating the code the way you need it.

However, when you reverse-engineer the code, I gather EA cannot tell whether it would be a aggregation (hollow diamond) or composition (filled diamond) and it punts for a more generic association.  Without going into details, I imagine that the reverse engineering process can be tailored to what you need--possibly it has defaults--or you have to intervene and modify the association by hand.

Bruce,

I disagree with your statement :

Quote
IMO [snip] aggregations and compositions have little use at the physical design level.


Although it is true that during initial design it is important just to determine the association--regardless of whether it's aggregation or not, hollow/filled diamond, navigability, etc., I believe it is important to qualify the association correctly.  In our environment we make sure that aggregation is expressed correctly: filled diamonds depict the same lifetime for the container and contained object, while hollow diamonds reflect separate lifetimes.

I compare this to use case design, where you start up by identifying the actors associated with a given use case, and you don't care about who starts the use case initially, but after you're done with identifying the actors, then you start filling up the arrows to convey the initiating and receiving actors.

Regards,

Javier

23
General Board / Re: self messages
« on: November 09, 2004, 09:42:27 am »
I'm assuming you mean a sequence diagram? If that's the case, I don't have that problem.  I'm able to create a self message and place it between to other self messages.  Granted, when you create the message, the arrow appears at the bottom, but when you end up defining the operation, the arrow goes to the place where you clicked.  Moreover, you can move the message around with no problems.

I'm using version 4.10.732.

24
General Board / Re: Views on MDA....
« on: November 09, 2004, 09:34:37 am »
I think MDA is still in diapers.

I was reading an article by Grady Booch on the OMG site http://www.omg.org last night where he talks about MDA.

In my opinion, it'll be a few years before we can see true MDA tools--has been the same process for UML.  Even the books--at least the ones I've read--seem to agree that MDA is still a few years away.  I understand that there are some MDA tools out there, but to what extent they can produce a PIM?

Regards.


25
General Board / Re: How to convince my boss?
« on: November 09, 2004, 09:28:32 am »
I liked the quote (from Craig Larman?) about the value proposition and would like to extend a little on that concept.

To my company, the value proposition is not so much the UML tool.  We are a IBM Rational customer and have been for some years.  While Rose really lacks in terms of functionality, what it does it does it well enough for our needs.  Moreover, we integrate it with Rational RequisitePro and Rational SoDA for requirements management and documentation automation.  Since we use a development process, what we end up with is a software architecture document that contains what we need to successfully develop a system--or subsystem or component.  The value proposition from IBM Rational is the tool integration.  Don't get me wrong: Rose is not as complete as EA, but is complete enough.  I remember a methodologist saying that 80% of UML is class diagrams sequence diagrams and use cases, and that's what we use.  Ocassionally we'll use a state diagram, or an activity diagram, but it's definitely not the rule.

After I learned about EA, I tried to sell its value proposition to the company, but price is not everything.  It would be prohibitely expensive to maintain our current models, train personnel, etc., should we migrate to EA.

Now, going back to your original question--although it seems that you've already convince your boss--what is the value proposition from Enterprise Architect?  To me that's the question to answer.  It does not matter if something is $100, $1,000 or $10,000.  For some companies, $10,000 for a tool in the large scheme of things are peanuts if you're going to be making 10 million.  For other companies, paying $1,000 is too much.

So, my recommendation is to take a look at what the tool does and how well it would accommodate your needs.

26
General Board / [BUG] Association displays dashed line
« on: November 09, 2004, 08:30:42 am »
When an association is being defined, dragging the association from a class outside of the diagram, Enterprise Architect displays a dashed line.

Steps to reproduce:

1. Create a class diagram.
2. Create a class (ClassA).
3. Select one of the association icons (Association, the one with only a solid line).
4. With the
mouse button down, drag from ClassA outside of the diagram.

At this point, EA displays a dashed line.

The workaround is to minimize and restore EA.

I am using version 4.10.732.

27
General Board / Self-Associations Limitations
« on: November 09, 2004, 08:24:44 am »
I'm generating a self association BUT there are no resize handles--only move handles to move the association to .  I tried using the Current Connector toolbar to set a custom routing but didn't have success.

I need a larger--or custom-sized--association to be able to write longer role names and constraints.  The current size is just too limiting.

Is there another way, or should I post it as an enhancement?

I am using version 4.10.732.


28
General Board / EA UML 2 Compliance
« on: November 02, 2004, 11:43:59 pm »
Has a UML 2 compliance been released by Sparx, or has anybody taken the time to determine how compliant EA is?

Case in point, I'm creating a sequence diagram and I can see at least the following non-compliant points:

- Participants are underlined.  In UML 2 are not objects, therefore they shall not underlined.

- Cannot find the Stop EventOcurrence (the X to terminate a Lifeline).

- Presentation option for coregion area.

Regards.

29
General Board / Re: Documentation options
« on: April 29, 2004, 09:09:07 am »
Craigh,

Seems to me that you would get better mileage if you submitted this as a feature request in one of the other folders.  It should not be that tough for the company to add omit documentation.

Regards,

Javier

30
General Board / Re: creating generalization when synchronizing pro
« on: April 29, 2004, 09:05:12 am »
It seems to me that EA still has glitches when reverse engineering code--sometimes code originally generated with EA.

Try reverse engineering the same code in another model, and if it gives you the same results--the generalization--then submit it as a bug.

Regards,

Javier

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