{ by david linsin }

October 12, 2009

Book Review Dynamic Modules for OSGi

Apress was kind enough to pass me a copy of this book, which I agreed to review in return.

I have been sitting on Pro Spring Dynamic Modules for Osgi(tm) Service Platforms for a while, although I got a fresh copy right after if was released earlier this year.

One reason for this might be, that after reading the first chapter, it felt like I was reading a manual rather than a book. Personally, I like a little bit more subjectiveness, because it improves the reading experience significantly. The author should spice up the dry material, so you won't get bored that easily. Unfortunately, that's what happened to me - I got bored. However, let's turn the spotlight to the content of the book.

The introduction chapter on OSGi is sufficient to get you up to speed. There are about 60 pages of Spring introduction. However, I think you should at least have some practical experiences with Spring, before digging into Spring Dynamic Modules or even Spring DM Server. It's simply not enough to explain the technicalities, to get someone an understanding of what Spring an its concepts is all about.

There's lot's of code in the book, which you can download and play with. If you like to read code, printed in a book, you are probably gonna like "Pro Spring Dynamic Modules for Osgi". For me, a book is not the preffered media to consume code. I have nothing against small code samples, but having pages over pages full of code, is really confusing and hurts readability.

The manual kind of feeling of the book continues the further you keep reading. Let me give you a concrete example: In chapter 4, called "Spring Dynamic Modules for OSGi", the author explains how the scope attribute of a bean declaration works:

Unfortunately, the how is all there is to the explanation. I expected a real life example of when to use the scope attribute and where it might not be suitable. I do understand, that the book can't go into details all the time, but especially those powerful Spring DM features like scoping, deserve more spotlight. Most of the time, the book stops when it gets interesting and you are left with your own imagination of how to apply that particular feature.

Despite the criticism, I got some neat tips from the book. The author suggests to split the OSGi dependent and traditional Spring configuration to make life easier for testing and mocking. I also gained a lot of knowledge from chapter 6, called "Versioning with OSGi and Spring". The author explains the concepts and implementation of versioning most of the time in a very understandable manner.

Overall, I think Pro Spring Dynamic Modules for Osgi(tm) Service Platforms is a reasonable reference book, with a nice sample application. If you are new to Spring and OSGi, you might have a hard time understanding the use case for those technologies, so I'd suggest to get this book as an addition to some basic reading material.


Daniel Schneller said...

Thanks for a realistic and critical review. This is what I thought of the book when reading a sample from it. I, too, would have liked a little "personal touch" in the writing style.

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