Visual Modeling Technique

by Daniel Tkach, Walter Fang, and Andrew So

Reviewed by Mark Lorenz

Visual Modeling Technique (VMT) is a book about developing software systems using VisualAge. It is part methodology and part product marketing. I have been on projects that actually used VMT successfully -- of course, I made some modifications to what's in the book, and I would advise you to do likewise. More about that later.

The VMT book doesn't add a great deal to what exists elsewhere in the industry. Instead, it documents what was and is in fact happening: projects pull different techniques from different methodologies to come up with something useful that works in real life. Of course, there is the "merging" of methodologies going on in multiple places in the industry, most notably the purchasing of well-known methodologists by Rational (and thereby purchasing the dominant methodology position in the industry). Don't get me wrong - documenting these pieces together is a worthwhile thing to do. (Note that if you have copies of IBM redbooks dealing with OO development, you probably have a good deal of the contents of the VMT book, albeit in a different format.)

One thing about VMT is inescapable at this time. If you are going to be certified by IBM as a VisualAge developer, you will need to be familiar with the contents of this book either from reading it or through other materials. As someone who has gone through the assessment process and is also participating in the ongoing certification program materials development, it is clear that at different steps in the process you will be expected to understand object-oriented analysis and design (OOA/D). Since VMT draws heavily from other sources in the industry, you can make it through the certification process without reading the VMT book, but you may have a harder time.

The book has valuable gems scattered about, such as:

"frameworks are domain-oriented, while design patterns are domain-independent" (p.116)

It also has mappings of OOA/D assets to the VisualAge development environment (mostly Smalltalk, but also Java and C++). For example, the tables in the design section of the book map OOA/D use cases to VisualAge visual parts (p.111). These are helpful for those using the VisualAge products for their object-oriented programming (OOP). There are also plenty of examples of implementations of sample code in VisualAge development products.

Some of the major drawbacks of this book are:

·1 VMT focuses too heavily and too early on the GUI. This is probably due to the emphasis on using VisualAge as a fundamental part of the methodology. GUI prototyping is important but after you have discovered the key parts of your business object model.

·2 The backbone methodology is Object Modeling Technique (OMT) (p.30), which is more data-oriented than I like to see. I recommend more of a behavior approach, such as Responsibility Driven Design (RDD) or Object-Oriented Software Engineering (OOSE) as the backbone, with OMT used as part of the static model notation.

·3 The chapters on using business rules (p.300), distributed Smalltalk (p.394), and SOM (p.383) seem to be IBM marketing brochures tacked onto the book.

·4 Some activities, such as state diagrams, seem to be thrown in to "check off" some list of topics to be covered. They are not really discussed in enough detail to be used based on the VMT book alone (I know that most OO projects don't need any/very many state transition diagrams).

·5 There is some poor advice (at least in my opinion) scattered about, such as:

"CRC is most effective for identifying object responsibilities and collaborations after the initial OMT object model has been built." (p.31)

None of these deficiencies are insurmountable by any means. I mention them to make sure readers - especially readers new to object technology - are aware of them.

Overall, I'm pleased with the VMT book and can recommend it, as long as the caveats noted above are taken into consideration. The book is especially of interest to VisualAge developers, since all examples use those products. Also, all related products work with VisualAge. Finally, the content of this book is helpful in becoming a certified VisualAge developer. The book adds less "new" information to the industry than some other books, but it is definitely worthy of a place on a VisualAge developer's bookshelf.

You can order this book through Amazon.com!

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