Customer Reviews

SOA Principles of Service Design

5 star:		(26)
4 star:		(1)
3 star:		(2)
2 star:		(4)
1 star:		(1)

 

 

Where do I start?
On the positive side. It is the only computer book I have read in years that is completely free of typing and grammatical errors.
On the negative:
Thomas Erls' previous book contains lots of valuable information about services. This book does not.
A good design book would have contained more.
Every time he starts to discuss something of depth, it is always beyond the scope of the book, contained in the companion Design Patterns book or in a book that he has yet to write, or he references another chapter containing a paragraph of clarification. The OOAD section is great, but that's not the topic of the book.
You know those articles where the text is great, but the diagrams confusing and innane. Well in this book, the diagrams are inane and so is their description. Take for example, page 327. There is a drawing of a stationary car and a moving car. The text reads "State refers to the general condition of something. A car that is moving is in a state of motion, whereas a car that is not moving is in a stationary state." What enlightenment. Another figure, Figure 8.10 ( I know it well ), is repeated 4 times on two pages, and at various other places, with only changes to the text. I can't help but feeling, that if I read all of the following books that this one promotes, I may get one book's worth of content.
I know that my review differs from the others. I have extensive experience in design ( although not SOA design ), and found most of what was discussed repetetive and obvious. Also I can't help but notice when I look at other reviewers' profiles, they have only ever reviewed one book, or at most two.
I will probably buy, or at least checkout the SOA patterns book ( referenced extensively in this one as published, but lost in book desert ). I hope it contains the content that this book should have contained.

This book is beautifully produced. The printing is first rate, the multi-color format is very pleasing to the eye, it smells wonderful, and it is superbly copy-edited (I caught no typos or grammar atrocities as is typically par with technology books). The content you ask? Well that is a bit secondary I am afraid.

While the copy-editing is first rate, the content editing is in need of some work. There is some really excellent content in this book but it is too often mired in beautiful but banal diagrams and structurally sound but superflourous text. It simultaneously suffers from both redundancy and paucity of information. The reader is too often referred to other books in the series, websites, or other sources of information.

In the end I think that there is some great content here, but I am afraid that many readers will give up in boredom or frustration before digesting all of the content.

This book is excellently produced in terms of presentation and content. That in itself is a hint that it is neither a fact book nor a how-to guide. It has no other intention than to sell the reader on the idea of SOA. Yes, it does describe the various technological concepts and principles but it does not contain a discussion of what it actually means to do SOA and what problems you will encounter in the real world.

it is a lot of money for a piece of marketing. If you need to sell SOA to your C-level management then this is a good way to do it. If you want to know how to deliver on the promise of this book then you will find that there is not much out there. What is however happening is that the term SOA is being redefined and changed continously so that in the end, the people who promoted it can turn around and say: 'See we did it after all!'

I still think that we should focus on the business user and his needs and not on a piece of useless archtitecture. This is where in my mind this book fails. It does not help me to improve IT for the business users and therefore it does not help the business. More on my blog: http://isismjpucher.wordpress.com

"...but it stinks." (Oscar Wilde)

This book, like others in the Thomas Erl SOA series, suffers from being long on words but short on actual content. Everything is presented in such an abstract and meta-level way as to be almost useless. I get the impression that the end goal of the methdology described in this book is to produce more documentation, rather to to produce actual, functioning services. Read a few hundred pages of this book, then step back and ask yourself, "What exactly have I learned that I couldn't tell someone in a couple pages?" In addition to all the wordiness and redundancy, almost every topic refers the reader to some other Thomas Erl book or website for more complete information. And of course, the delightful pointless diagrams...

My real question (and I'm not being snide here) is, "Who *is* Thomas Erl?" What exactly are his credentials for presenting himself as the "guru of SOA?" The bio and testamonials on his website all present him as an expert precisely because he has written all these books. There's no other background about him. Where did his expertise come from? Has he ever actually worked in the industry? Or is he someone who recognized SOA as the next big software "thing" and was lucky enough to write the first book? In other words, like some of those personalities on "Hollywood Squares," is he famous simply because he's famous? I don't know; I'm asking.

Certainly the fuzzy, "meta-" quality of information in his books (and I've slogged through two of them so far) doesn't give me the sense that I'm reading the clear, incisive thoughts of someone who's actualy worked in (and mastered) a particular domain. People who really know what they're talking about can generally communicate an idea very succinctly. That isn't the case with this book.

This was a very timely book for me to read, since I am currently writing a new course on Testing Service-Oriented Architectures. This book has a very well-defined aspect of SOA, namely the design of services. Erl is very clear that this book does not cover topics he has previouly addressed in his other books on SOA, nor does it cover SOA standards since adoption of these proposed standards is not on the horizon.

With that said, I really appreciated the organization and presentation of this book. I have been reading some other titles and found this book very understandable. There are many illustrations that help explain the concepts of service design. The scope of topic coverage is also good. After explaining basic design of SOA, Erl covers topics such as service contracts, service coupling, service abstration, service reusability, service autonomy, service statelessness, and service discovery.

The book concludes with a discussion of Object-orientation and service-orientation, supporting practices, and mapping service orientation principles to strategic goals. There is also a case study that is referenced throughout the book to give a real-world application to the concepts explained in the book.

I found this book to be very readable, so anyone with an IT background should be able to understand it. Design experience would give an added perspective in understanding this topic, but others in the organization such as testers, business analysts, etc. should be able to profit from this book.

This is also a good reference book on service design. I could pick up the book, find a topic and immediately gain understanding of the topic. I like that!

One final thing I appreciated about the book was the lack of reference to specific vendors and tools. Not that tools and vendors aren't an important part of the SOA picture, but this vendor-neutral approach makes the book applicable in any environment.

I highly recommend this book to anyone who is involved in SOA design, people who may be investigating SOA as a new direction in building and reengineering systems, and people who just want to gain a better understanding of how services are designed. For testers and other software quality professionals, this book can form the basis of designing tests for services.

Readability - 5
Applicability - 5
Coverage of topics - 5
Depth of coverage - 5
Credibility - 5
Accuracy - 5
Relevance to software quality - 5
Overall - 5

What this book is not: it is not a handbook for architecting an SOA (try Erl's other book, Service-Oriented Architecture (SOA): Concepts, Technology, and Design (The Prentice Hall Service-Oriented Computing Series from Thomas Erl), for this). Nor is this a book for developers looking for code examples, WSDL pointers, or the like -- there's no code in this book, other than sparse snippets of XML schema.

What this book *is*: a stellar handbook for designing the services that participate in an SOA. If you have designed a suite of services and are looking to improve them, or are about to design a suite of services . . . then you're irresponsible if this book isn't on your desk. In particular, this book helps you think, in a structured way, about what makes *good* services.

The book starts (part I, about 100 pages) with a drive-by overview of service-orientation and design principles -- not much new here, but gets you in the mood.

Part II, the meat of the book (about 300 pages) gives you what you're really looking for: crisp, interrelated, cohesive principles for designing quality services:
- Contracts
- Coupling
- Abstraction
- Reusability
- Autonomy
- Statelessness
- Discoverability
- Composability
Rather than just ticking these off, Erl describes each principle in terms of the other principles, provides an analytic framework for assessing suitability and compliance, describes both positive and negative characteristics of the principle, and illustrates the principle in the context of an imaginary case study (surprisingly effective -- rather than the usual banal dialogues, the "case studies" include practical guidance and analytic insights). Throughout, as other reviewers have noted, the production quality is great (solid, consistent diagramming and easily-readable/flippable layout).

Part III has a useful comparison between OOAD and service orientation, a useful processes/glossary/roles section, and some bookkeeping.

Service oriented computing (SO), as defined by author, is popular generation of distributed computing platform with its own set of goals, design paradigm, architectural model, pattern catalog and software development methodology. SO inherits all of the primary OOAD goals and further increases their scope and adds others. Although they both share some design principles in many they differ - mostly because of missing inheritance principle. SO historically evolved out of approaches like EAI, BPM, WS, AOP, OOP while OOAD out of procedural programming, RPC, modular development, etc. Although SO historically follows OOAD it is not its complete replacement but rather complement that might be combined with.
The book establishes vocabulary of terms related to service oriented computing, defines and describes its goals, design principles and characteristics. Conscious application of principles lead to characteristics that might qualify design as good in terms of achieving goals always associated with defined characteristics. At the end of the book there is brief comparison between goals and principles of SO and OOAD respectively and brief overview of SO analysis and design process. While describing individual design principles their mutual relations and associated risks author also provides reference to design patterns, which help to proliferate them.
The book is very well structured and supplemented by expressive pictures and elegant graphics. However it is not guide to SOA analysis, design, patterns or implementation technologies like popular WS. It is really book of what service oriented computing is, what are its goals and design principles. Despite the structure is great, the language used in content is highly abstract, vague leading to definitions that are not precise and stay unclear, circularly referring to each other or to concepts not explained in the book at all. Many chapters contain text, which simply don't relate to the topic repeating sections earlier in the book or referring to unrelated and distracting content. Style used on many places is informal and distracting. My final impression is that the book was created in a hurry out of single unstructured article and filled into schematic structure ex-post. I miss clear expression, logic and relevancy on many places to be able unambiguously interpret and fully understand what has author meant. If I knew it I would never pay such amount of money despite some positives ...

The book is a continuation of Erl's dive into SOA that he started with his earlier books. The difference is that this is more of a practitioner's handbook than anything else. The text is lucid and to the point. The case studies at the end of each chapter to discuss the concepts covered are also invaluable.
If you're looking for a book that contains implementation specific, how-to's (e.g. with Java/JavaEE,WcF) then this book is not for you. If you need a conceptual and technology agnostic, yet practical, guide to implementing SOA, then this book is quite indispensable.

Thomas Erl is an SOA book machine...the next one is scheduled for 2008. The good news is that, as far as I am concerned, it's only getting better.

Here are another 531 pages filled with expertise. And for all the ones who don't think quantity matters, just read the first 100 pages. Those alone are worth getting the book for. If you are a CIO who wants to understand what SOA is really all about, read those first 100 pages and the lightbulbs will go on!

For serious integration architects, I couldn't imagine a better way Thomas Erl could have structured this book. It really has it all: (a) a case study that weaves itself through the entire book. I don't know about you, but when I had to study in college it were always the examples that helped me make sense of all the theory (b) great visuals - I am a visual person, and I know many others are. The graphics in this book are very helpful to make this an easy read! (c) as any Thomas Erl book, a clear and precise structure.

Don't expect the latest standards or programming code. But if you want to discover the architectural beauty behind SOA, pick up this book.

Thomas Erl, who has previously written two of the most practical and useful guides to creating Service-Oriented Architectures, has taken a step back to survey the field as a whole. When his first work hit the scene a few years back, service orientation was still immature, with few practitioners, a lot of buzz, and almost no standardization. Now that the concepts have matured, this work goes back to the basics, to the principles that underlie the concepts of service orientation, and creates a lexicon for the industry.

The lingua franca spelled out in this work enables service architects to communicate clearly and precisely about service principles. With an encyclopedic approach to the principles, it's easy to pick up and read the topics out of order, and each pass through offers new insights and interrelations. The diagrams and illustrations throughout elucidate the topics and serve as standalone discussion starters for architects everywhere.

I highly recommend it as a common read for your service-oriented team.