Enterprise Integration Patterns: Designing, Building, and Deploying Messaging Solutions (Addison Wesley Signature Series) (Hardcover)

The book arose from a Patterns conference where patterns for connecting different apps were discussed. The list of patterns was developed collaboratively by industry experts on the website http://www.enterpriseintegrationpatterns.com.

I've spent the past three years integrating hundreds of applications following corporate acquisition, disposal, outsourcing, and consolidation inside a large bank. This book summed up very precisely what I learnt in the first year. It does not go into more complicated patterns such as "Compensating Transactions" and "State Synchronization", but it covers the basic 50 everyday patterns of design very thoroughly.

The book is part of the Martin Fowler and Kent Beck series and this shows in the quality. It is highly readable and thoroughly peer reviewed.

Often when designing enterpise system one can get lost in detail. This book is about taking a step back and thinking about how the components in the enterpise architecture interact with each other, and how this messaging interaction can be modelled using UML-based techniques. I say UML based because the authors have developed their own descriptive diagrammatic notation that is extremely easy to follow. This messaging interaction takes the form of 70 or so patterns that describe messaging scenarios.

You have confidence in the authors, you know they know what they are talking about and have distilled their real-life experience with large scale enterprise solutions into real life problems and solutions. Whether you are from the .NET or J2EE camp, you will find what you need here if you are involved in building enterpise systems.

If you are looking for a book that gives you all the answers (and code) then this is not it - what it does give you is a number of ways of reasoning with example code to provide you with the ammunition to develop your own solution in a logical and progressively thought out manner. The text is informative, clear and uncomplicated with adopting a patronising tone - it just tells you what you need when you want it.

I really would recommend that this becomes part of your programming book collection, and when you think that you know how to design something, stop and open the book!

The only downside is that not all the source code is available in the accompanying website, oh well can't have everything.

If you are not sure about buying this book, then check out http://www.eaipatterns.com/ that will give you a real flavour of what they are talking about.

The book is very accessible, written and illustrated clearly and assuming very little initial knowledge. However it will also provide value to the experienced messaging developer, formalising his or her knowledge and suggesting new ways of using messaging to solve different problems. I particularly like the way that Hohpe and Woolfe lay out each pattern using language and visual styles to naturally delimit the sections of the pattern, rather than using lots of sub-headings. This increases the readability significantly.

Several books on patterns talk about a "pattern language", the idea of describing a complete design in terms of named patterns for the architectural form of each component. However this is one of the first books I have read which really adopt this idea - the authors have created a new visual language, which they first use to describe basic patterns in terms of basic message constructs, and then describe more complex patterns and solutions using the icons for the intermediate patterns. Best of all you can download a Visio stencil from the website and start using and extending the pattern language yourself.

The book is remarkably technology-agnostic, providing many examples in both .NET and Java forms, and with a fair sprinkling of other technologies, for example using proprietary EAI tools such as Tibco. I have certainly seen and used some of these patterns in older file-based integration schemes, and I suspect many of them work for Web Services too. As such the book has a much better claim to be a true "patterns" book than one wedded solely to a single technology base.

Each group of pattern descriptions is followed by a detailed "practical example" section which shows how one or more messaging technologies can implement the preceding patterns to solve real problems. There aren't any real "antipatterns" in the book, but the book is realistic about when a given technology or pattern should not be used, which is just as valuable.

If I have a complaint it's a minor one, that the book is too long. Including the multiple introductions, it runs to over 700 pages. Dipping in and out my read through has taken many months. Like many patterns books, in an attempt to keep each description self-contained you find by half-way through that some basic things are being repeated regularly. A more "normalised" structure might have been better. Also, although most of the book is very readable, a couple of chapters by "guest" authors, including the final one on Web Service standards, take a more academic tone.

That said, this is an excellent book, which can be read from cover to cover, or stands as a general-purpose reference, and I strongly recommend it.