For a review of Mastering Xpages, I could copy almost wholesale the introduction from my review of XPages Extension Library: the low count of XPages books makes each one an essential purchase. As before, fortunately the book rises above that obligatory baseline and is absolutely worth your time. That's the upshot of this review: if you're a Domino programmer, buy and read this book.

Size

One of the first things you notice about the book is its size, clocking in at over a thousand pages. This is a function of the complexity of the platform and the breadth of its intended audiences. Due to its role as "the" XPages book, it contains content meant for people ranging from legacy Domino devs, experienced XPages devs, people entirely new to the platform, and JSF programmers new to Domino.

Fortunately, the structure of the book makes this manageable. Particularly once you get to Part IV, it is essentially a collection of self-contained topic references. Though it would be a good idea to read through the entire thing, there are large sections that you can hold off on until you have a need, such as XPiNC, mobile development, and internationalization.

Changes Since Last Time

The original edition of Mastering XPages was written for Dominp 8.5.2, before the Extension Library and before knowledge of real XPages development had really started infusing the community outside of a couple teams. The additions since the previous version focus largely on the "mainstreaming" of several Extension Library controls and concepts (without going into the exhaustive coverage of the Extension Library book proper), further coverage of Java's role in XPages development, and sort of a "best of" of IBM's releases in the interim: the XPages Toolbox, improved debugging, Tony McGuckin's Masterclass series on performance and scalability, and even the Rich Text Editor Evolution control. These provide a much more well-rounded view of what modern XPages development actually consists of, beyond the comparatively-primitive (and buggy) options in a stock 8.5.2 installation.

Java

I was very pleased to see heavy coverage of Java development in XPages, starting off early (and possibly intimidatingly) with a chapter on XPages' JSF roots and the Java classes/interfaces that make up its true form. To suit the various target audiences, this coverage runs the gamut from creating managed beans, to logging/performance tracking, to creating controls and renderers whole-cloth.

However, I'll admit that I wished there was another level represented: writing your business logic in Java, probably via managed beans. The IBM-advocated way is to use SSJS for business logic and use Java when you have a particularly JSF-related need, though, so the lack of this topic is a result of that.

Lack of Opinion

My primary quibble with the book is basically the same as my problem with the platform as a whole: it's not opinionated. XPages, as a platform, is massive, and trying to understand every moving part is likely impractical for anyone whose job isn't focused on either writing or manipulating the entire thing. As a Java-based framework, it carries enterprise Java's tendency for massive class hierarchies, factories, layers of configuration, and several types of indirection. As a system grafted on top of Domino, it bears the scars of merging with a platform and development ideology often at odds with JSF's origins. And as a modern web framework, it requires involvement in the dizzying array of web technologies and idioms.

The result of this is that it's often largely unclear what the best way to accomplish a task is. It's outside of the book's bailiwick to establish this One True Way (to my knowledge, no such Way exists for XPages), but the state of affairs leads to some potentially-confusing results.

On a micro scale, there's the example of resources in themes. Themes provide two syntaxes for including JavaScript and CSS files: the "legacy" way (<resource> elements) and the good way (the <resources> element and its XSP-alike children). The book mentions both, and even explicitly describes the latter as the one to use, but it, like Designer help and the default comments in a new theme file, still uses the older style for the actual examples. It would be better to mention the existence of the old style for in case you run into it, but otherwise ignore its existence.

On a macro scale, what the book lacks is a guide to building a full application. The book is rife with downlodable examples, and those are helpful, but I think it could be all the better to demonstrate building one of the canonical "tutorial"-type apps, such as a to-do list or store. An example of using each main topic in the same from-scratch app (CRUD basics with Domino documents, building a layout using Application Layout, mobile-enablement with the mobile controls, adding internationalization, and finally performance monitoring and tweaking) could provide a valuable guide to how to build a solid, performant XPages app. The use of the discussion app does a bit of this, but most of that app is already written, and it's not a consistent thread through the book.

Conclusion

Overall, gripes aside, my original opinion remains: this book is a valuable resource for any Domino developer. Its value goes beyond the initial reading as well, as it will be a powerful go-to reference tome for major subjects (especially if you get the ebook version and can just search). For my part, I expect the chapter on building components to be particularly useful as I delve further into the topic. If you haven't purchased this yet (or coaxed your company into purchasing it for you), remedy that immediately.