I’ve managed to give the jBPM Developer Guide by Mauricio Salatino, which was sent to me less than a mont ago by the people of Packt, a thorough read. Reviewing a book is not a simple task, certainly not when the topic is quite familiar. So I started every chapter by writing down some notes of what I would expect to find, and checked while reading if the content could cover my expectations.

Since many people will simply skip to the conclusion part (at least, that’s what I do when I read a book review), I’ll start off with The Short Review.

The Short Review

Basically a book review needs to answer the following question:

Would you recommend the book?

Yes. I would certainly recommend the book to any novice jBPM user. The book covers practically all jBPM3 concepts and gently builds up the complexity of the content. Having this book a few years ago when I started out with jBPM, would have saved me tremendous time. Granted, the book has some minor flaws (see The Long Review), but it currently is the best guide and reference when you want to start using jBPM. period.

The Long Review

In the following sections, I will summarize for each chapters the notes I’ve taken while reading the book.

The book is published by “Packt Publishing”. The nice thing about Packt is that they are generally fast to publish books about new and exciting, mostly open source technologies. On top of that, they also invest a part of the profit back into the project, which is a noble deed if you ask me.

In general

• This book is about jBPM3, not jBPM4. One might think this is a bad thing, but do remember that jBPM3 is extremely stable and is part of the JBoss SOA-Platform for many years to come (today jBPM3 is the only official supported version by Red Hat – these things take quite a time). People that are familiar with jBPM3, will have no problems to make the jump to jBPM4.
• A general nuisance is the language usage throughout the book: although the sentences are syntactical correct, they often not feel ‘right’. Others have already commented on this fact, so I’m not going into it here. I don’t blame the author: he shows a great amount of enthusiasm and jBPM knowledge, but with a little more editorial reviewing, this book could have gotten that little extra edge.
• The book is great for jBPM starters, no single doubt about that. However, I would have liked to see more ‘best practices’ and advanced configurations (JMS/SOA/etc.). Let’s hope for a next jBPM book that covers those topics

Preface and Chapter 1: Why developers need BPM

This chapter is a bit overwhelming for beginners. The author tries very hard to convince people of the rightness of open source software (which is perfectly valid ), but it’s too heavy as a starter chapter. This chapter would have been a good appendix, I guess.

Oh yeah, I don’t necessarily agree with Mauricio’s definition of a ‘BPM suite’. You’ll understand it when you read it

Chapter 2: jBPM for Developers

Good introduction to some important concepts like wait states, nodes, process definition vs instance, etc. The downside of this chapter is that it tries to explain these concepts by building a simple state machine in Java code. In my opinion, 99% of the jBPM starters will find this too overwhelming. I found it fun to read, but then again my day job is to build such “state machines”

Luckily, it goes uphill from here. My advice would be to read the chapters 1/2 after starting from chapter 3, and only giving them a quick read either way.

Chapter 3: Setting up Our Tools

Mandatory chapter for every beginner. I really liked the fact that nothing is “taken for granted’, as tools like SVN and Maven are also covered with some text. Many technical books assume that this is common knowledge, but experience has taught me this certainly is not the case. I also really liked the ‘community’ take on things in this chapter. The author explains and demonstrates that by knowing maven, svn, etc. every one can contribute to open source ecosystem. As a core jBPM dev, I was happy to find these encouragements.

This chapter demonstrates in depth how tools (Maven, Eclipse, etc.) need to be configured to get the maximum out of your jBPM experience. Also the jBPM project structure is touched, which is in reality a true knowledge advantage I’ve not yet seen in many jBPM users.

A small side remark (has no influence on jBPM novices, ofc.): the history of jBPM is a bit skewed, which is a bit of a pity if you’re closely involved with the project (eg. jBPM was orginally not created by JBoss)

Chapter 4: jPDL language

When I was reading this chapter, I noted down “To the point! This is the content you need”! I can’t express it better than that. A must-read chapter for every jBPM adept.

I was delighted too see that the author often explains functionality by referring to snippets in the source code. In my opinion, this is the way open source tech books should be. When I was still a jBPM consultant, I often looked at the source code to learn how corner cases where handled, or what exactly a certain operation does, etc. As Ronald often states on the jBPM User Forum: the best documentation is the source.

Chapter 5: Getting Hands Dirty with jPDL

In this chapter, the topics explained in the previous sections are used in a real project. The use case is interesting and has great didactical value. I had some reservations when I read the use case, and noted down some questions on how the author would tackle them (if they were tackled at all). I was happy to find them all answered by the end of the chapter. Perhaps a small remark could be here that the jBPM configuration isn’t showed in this chapter. This could be a bit confusing for some starters, since it involves some “magic” that is easy to explain.

Chapter 6: Peristence

Really thorough and detailed explanation of jBPM persistence. Excellent transaction explanation and great diagrams that explains what happens in which situation (automatic nodes, wait states, when updates happen, etc.). Really every aspect is covered (for example even Hibernate caching is touched), nice!

Imo, perphaps the best chapter of the book.

Chapter 7: Human Tasks

Perfect follow-up for the previous chapter. Good, detailed content about probably the most important construct of any BPM engine. I also really like the webapp approach at the end of the chapter: this is the stuff why people buy the book.

Chapter 8: Persistence and Human Tasks in the Real World

This chapter perfectly aligns with the previous Human Task sections: good and very detailed content.

Chapter 9: Handling information

Great explanation about variable usage in jBPM. The content is good for starters and should get you going quite far. But in my opinion, some things should have gotten more attention, since variables are an area in which many mistakes are made in real life projects. Some topics that could have gotten more love: hibernate objects as variable (+ why !), serializable (what about synchronisation problems?), business keys for process instances (why do you need them).

Chapter 10: Advanced features

This chapter definitely covers some advanced features. It even managed to surprise me: I had totally forgotten about the superstate indirections using “../” in the node names (altough I’ve used it a lot on a certain project) and the book mentioned this little detail! Also start tasks were covered – nice!

Some topics which I have needed a lot in my past projects weren’t covered (but this is really advanced stuff, and definitely not for startes): subprocess binding, more database schema focus, e-mail node and custom HQL queries using the jBPM objects. So altough I really liked the chapter, it could have gotten extra points when dealing with those topics.

Chapter 11: Advanced topics in practice

Not to miss chapter since here asynchronous execution is explained. The books goes really deep in the nitty gritty details of async executions – which I like. However in my opinion, the book doesn’t stress enough the crucial importance of the async functionality enough. But after reading this chapter, you’ll definitely be able to understand and try it for yourself.

Chapter 12: Going Enterprise

Explanation of what the jbpm-enterprise jar offers. Some good practices are states here, like the EJB intermediate layer with ids (jBPM4, anyone?). Also remote client usage is covered, together with Timers and job (VERY good explanation btw).

As my conclusion already can be found in the beginning of this post, I’ll repeat here the one-sentence summary. If you are starting out with jBPM, there is no better book or guide to get you guys. Highly recommended!