c++ - How to create class diagram from source code using either Enterprise Architect or Rational Software Architect?

Question

I am not fluent in UML, but I would like to create a class diagram based on existing C++ code. Other StackOverflow questions have indicated that two programs - Enterprise Architect and Rational Software Architect - are fairly good at "reverse engineering" C++ code (i.e., creating UML class diagrams based on existing C++ code).

I have downloaded the trial version for both of these applications. However, I cannot make any headway into understanding what to do to create a class diagram in either of these applications.

In Rational Software Architect, I have created a UML project, but I cannot find any way within the program to select, and reverse engineer, my existing C++ code.

In Enterprise Architect, I was able to import my C++ code, but all the elements (classes) appeared in a useless, overlapping diagonal line within the diagram. I attempted other settings, such as circle, but these were equally impossible to read because the diagrams were so large (due to the attributes and methods taking up alot of space) that no amount of panning and zooming was useful. What I would like is to hide everything except the class names (i.e., not display any methods or attributes) so that all 20 classes appear conveniently and legibly in one screen.

However, I am unable to find a way to hide everything except the class names. Rather, when I found an option (in Enterprise Architect) that seemed like it might hide everything but the class names, for some reason the elements all vanished in the class diagram, and no amount of repeating the steps & deleting and re-adding packages made the class diagram reappear.

Note: My C++ code (at least those files I selected for import into Enterprise Architect) amount to only about 20 classes.

Sadly, a very careful search of the documentation for both of these programs provides only generalities - no specific instructions are given regarding reverse engineering for either of these programs, so far as I could find.

I would be grateful if someone could tell me the basic steps to create a legible, easy-to-navigate diagram via. reverse engineering (i.e., C++-to-UML) that shows only the class names, so that about 20 classes fit (legibly) on one screen, using either Enterprise Architect, or Rational Software Architect - OR any other tool whatsoever that is capable of doing this (I suggest EA and Rational only because they have been highlighted in other StackOverflow answers as the best programs available for this purpose).

Answer 1

This answer applies to EA.

You can import individual files or whole directories, recursively or no. Directory import is by far the most common case; single file import does not allow you to create a diagram automatically.

When you import a source directory, you have the option of creating diagrams for each UML package, or no diagrams at all. You also decide whether to create packages for each source code directory, namespace (default) or file.

If your code constists of only 20 classes then it's likely they're in a single directory and/or namespace, so play around with that option (Package Structure in the Import Source dialog) to get the right number of diagrams.

In the same dialog, there's a button "New Diagram Options," which opens another config dialog where you can choose whether the diagrams should contain the classes' attributes and/or operations. You can also make the decision on a visibility basis, eg show public members only.

This dialog only affects what's shown in the diagrams when they are created. The members are still imported, just not displayed. This sounds like what you're after.

You can change the display options for any diagram by double-clicking an empty area of it, or right-clicking and selecting Properties. It sounds like you got into this dialog and changed something around, but I can't really tell what. The situation you describe, where you can't get the display back the way it was, is not one I've ever encountered in EA.

It is also possible to select display options on a per-class basis by right-clicking it in the diagram and selecting Feature Visibility. I don't recommend you use this in reverse-engineered diagrams, I'm just mentioning it for completeness.

The layout you describe, with all classes in a meaningless diagonal, suggests to me that the diagram isn't being laid out properly after creation. The diagram creation is a two-step process; first all the classes are dropped onto it, then the layout is applied.

This is strange, as EA automatically lays out generated diagrams and I haven't been able to find an option which allows you to deselect this behaviour. If this persists, send a bug report to Sparx Systems. You can always lay out the diagram by opening it and selecting Layout Diagram from the top-level Diagram menu.

If, finally, your classes are spread out among different packages and namespaces so that EA generates multiple diagrams for them, you'll have to merge them manually. Do this by opening both diagrams, selecting all (Ctrl-A) in one, copying (Ctrl-C) and pasting (Ctrl-V) into the other, then ask EA to Layout Diagram again.

So:

1. Right-click an empty package in the project browser, select Code Engineering - Import Source Directory.
2. In the dialog, select the root directory and source type.
3. Tick "Create Logical Diagram for Each Package" and select the Package Structure which best fits your source structure.
4. Click "New Diagram Options" and in the new dialog untick "Show Attributes," "Show Operations" and "Show Property Methods" if applicable.
5. OK both dialogs.
6. If multiple diagrams have been created, copy all classes into a single diagram.
7. If the layout looks bad, select Diagram - Layout Diagram.

Hope this helps.