The Elements of Uml(tm) 2.0 Style

I must confess, I love little books. In the inimitable style of the White and Strunk book, this one provides well-grounded and practical prescriptions for language usage. It is not complete as a learning tool, but it provides an excellent adjunct to the Booch et al 'User Guide' or Fowler's 'Distilled'. When I first opened the book I thought some of the style guidelines appeared trivial. But digesting it as required reading in a UML intro class not only gave me the confidence to complete my assignments; I found additional insight into UML as-tool. I suspect I will be vetting every UML diagram I create through this book's precepts for a long time.

With the release of UML 2.0 into the wild, it was inevitable that Ambler would update his Elements of UML Style book. Like its predecessor, this little book is more a companion than a teacher. You will not learn how to do UML modeling from this guide--that is not its intent--but you will learn how to make your UML models more readable and consistent. Ironically, books that do intend to teach you UML modeling do not talk about "goodness" or accessibility of the model's representation. This guide brings that balance to your use of UML. There are many "gems" sleeping in his book. In his section on the Sequence diagram Ambler recommends putting the message text near the receiver side of the message arrow. This is not subtle: it makes the model significantly easier to read--especially when evolving the diagram in real-time on a white board. "Prefer Names over Types for Parameters" is another, and especially true when modeling from an analysis mindset rather than describing design. I could go on, but that would be redundant. Get the book. Read it. Consider his recommendations, and feel free to go in another direction if you can justify that direction is an improvement in clarity and communication. Not everything Ambler says should be taken as "the way", of course. As an experienced modeler I have certain style preferences to which I gravitate, and which violate some of Ambler's precepts. In use case diagrams, for example, I always denote an arrowhead on the actor-to-use case association. I also note specific stereotypes on the actors of a use case diagram because not all actors in a system are equal in importance in the project lifecycle. But I follow, and have independently adopted, many of Ambler's recommendations. Indeed, I know that many of his recommendations are derived from the common usage of the modeling community, plus his own unique additions. If you are just starting out with UML diagramming, this little guide will help you adopt some consistency as you navigate the new landscape of 13 diagrams in UML 2.0. Not all of those diagrams are equally important, either, and I was very pleased to see Ambler clearly stating his reservations about the Composite Structure diagram. Many of us wonder about the value of this offering in UML when other issues such as data modeling and UI modeling have been so prominently absent since UML's inception.

When I wrote a review for the original book (The Elements of UML Style) I commented on Scott Ambler's fantastic style of writing. The simplicity with which he puts across even the most complex concepts is truly appreciated by this 20++ year software veteran. Scott subscribes to, and adheres to, the KISS principle (Keep It Simple, Scott!). That is what makes it so easy to understand and appreciate his style. In this book Scott has updated the original text to include the diagrams of UML 2.0 and to use and explain the new terminology that goes with them. More interestingly Scott has also included two styles of diagrams. This includes both nicely produced diagrams from some unknown software tool AND a selection of hand-drawn diagrams. Two of the practices of Agile Modeling (AM) are "Model to Understand" and "Model to Communicate". Very often as we first model to understand problems and their domains, we utilize the UML but in an informal way, such as through the use of white boards. So, to finally see a UML book with hand-drawn diagrams is a great step forward. Thanks, Scott! This book is small enough to fit in your pocket but is incredibly massive in applicability. It belongs on the desks of every developer (AND their manager!) working with UML. Whether applying UML in an agile environment or within the constraints of behemoth software development projects, a basic understanding of the UML is essential. This book will get your team there, quickly. Research shows that the number one factor that contributes to project success (or failure) is the ability (or inability) to communicate well. That was one of the goals of the UML, a truly UNIFIED language in the arena of modeling. A key value in Agile Modeling (AM) is communication. Coupled with the AM principle of Know Your Models and the AM practice of Apply Modeling Standards, this book will assure that your project's modeling efforts shine.

The goal of this book is to enhance your existing UML modeling skills, it is not to teach you UML. It assumes that you understand the fundamentals of the UML but now want to improve the way that you apply the UML in practice. By following the guidelines presented in this book, you will improve the quality and communication value of your UML diagrams. The book also includes some tips for properly applying the UML notation.

As with other "Style" books, this one is *not* meant to teach you UML 2.0, but rather to bring some consistency between / among stakeholders when actually applying its usage in the real world to increase effective communication. For example, UML models are used to explore and communicate your requirements, architecture, and design ideas, and by following the guidelines described in this book you increase both the quality of your models and the chance that others will understand what you mean. This book is a valuable reference for anyone using the UML.