Re: Popular Design Diagram Methods For Ada

["Jeffrey D. Cherry" <jdcherry@utech.net>]

My group has looked at a lot of Ada code.  The software that we've looked 
at was developed by different companies (I'm with the IV&V contractor).  It's 
almost exclusively Ada83, but there is some Ada95.  The various projects 
range in size from about 30KLOC to over 250KLOC.  As you would expect, we're 
always looking for better tools to automate the code analysis process.  We 
can't depend on the developer's software design diagrams since they often 
don't exist or are not updated through the long development cycle.  We also 
need to focus on the code, since its what actually does the work.  Another 
limitation is that we only have PCs on which we may do the analysis.  Thus, 
any tool we consider must run under Windows 95/98 or NT.  We have one Linux 
machine that we've just recently acquired, so things are looking up.

Given the above context, and if you're talking just code analysis ... not, for 
example, requirements tracking or automated testing ... then we've been using 
a tool called "Understand for Ada" by Scientific Toolworks, Inc.  They also 
have a C++ and FORTRAN variant of the same tool.  Their web site is at 
http://www.scitools.com.  We've found that this tool gives you the most 
bang for the buck.  It generates a variety of reports and diagrams that 
we've found quite useful, and the latest version (1.3, currently in beta 
but due out at the end of February) is an impressive improvement over the 
previous version (1.2.7).  The tool doesn't generate UML diagrams (I'll 
address that topic below) but the diagrams it does generate gives you an idea 
of structure and other dependency relationships.  The browser makes 
navigation of these diagrams easy and we use the text reports for additional 
processing and analysis.

We've tried reverse engineering options in tools such as Rational's Rose and 
Software Through Pictures from Aonix, but were unimpressed with their results.  
The reason these reverse engineering tools don't help that much is because we 
look at (mostly) Ada83 code and these tools generate UML diagrams.  Since Ada83 
isn't as object-oriented as Ada95, the resulting class diagrams are 
uninformative.  This isn't a failure of the tool but merely a consequence of 
the implementation.  What we would like to see in these reverse engineering 
tools, but haven't seen, is as follows:

1) Class diagrams should use the data type name for the class name, and 
component boxes should list all the explicitly defined primitive operations 
on the type.  Implicit primitive operations could be listed as well but 
should be "hidable" from the diagram.

2) Component diagrams should be generated to show the relationships of the 
source files and their resulting application programs and/or libraries.

3) For a given subprogram, generate an activity diagram.

Other UML diagrams are, IMHO, not creatable from the source without some, or  
a lot of, input from the user.  Use Case diagrams, I think, are not derivable 
from the code, but must be generated by the user(s).  Statechart diagrams 
would be very difficult to generate from the code due the variety of ways to 
implement a state machine.  Sequence diagrams might be generated for common 
GUIs, but would require help from the user for event definition and 
callback routines, and at the very least would require processing files 
other than Ada source.  Collaboration diagrams would be even more difficult 
since the interaction must be defined by the user.  Deployment diagrams may 
be generated but again require the user to define the partitioning of 
applications to nodes, etc.  Something that, once again, can't be derived 
from the source code.

If you have money that you can devote to a project, you may want to consider 
using ASIS to develop your own analysis tools.  We've identified several 
ASIS tools that we'd like to develop but simply don't have the resources.  
Also, if you use a real operating system (i.e. _not_ Windows), there are 
many more analysis tools available.

-- 
Regards,
Jeffrey D. Cherry
Senior IV&V Analyst
Logicon Space and Information Operations
Logicon Inc.
a Northrop Grumman company