Customer Reviews

Pro Jakarta Velocity: From Professional to Expert

5 star:		(2)
4 star:		(3)
3 star:		(1)
2 star:		(1)
1 star:		(0)

 

 

Harrop puts forth an interesting claim in his book. He offers Velocity as a significant improvement over using JSPs to make dynamic web pages. By now, at least in the Java world, JSPs in combination with servlets, is the most common way to do this. Not the least because it gives a clear implementation of the MVC design pattern.

But Harrop points out that JSPs always had an awkward syntax. Which for complex pages leads to miserable, error-prone coding. Plus, the pages might be slow to build. Velocity seems to offer a coding approach that is more natural than JSPs. And you certainly don't have to abandon MVC. Harrops shows how to reimplement MVC, while using Velocity and hooking to a database, and coupled to Struts and Spring.

The code examples in the book are not complicated. That too is part of his message.

You may want to look closer at the book.

I have always been a strong supporter of Velocity. I even wrote an article for JavaRanch about Velocity back in March. Velocity is an open source template framework designed to simplify the task of generating content such as web pages, email, or any other text-based output. The Velocity documentation available from Apache is short, low on examples, and leaves holes (even if it is fairly good compared to some other open source projects). This book fills in the gaps and gives excellent coverage of the many features that are available with Velocity.

The book starts with an introduction to Velocity and then explains how to install and configure it. The author then discusses the Velocity Template Language, examines its shortcomings, and demonstrates how to get around them. Best practices are covered early in the book. Although Velocity is normally thought of as a web-based framework, the author doesn't let us forget that it can be used for both stand-alone and web applications and gives us detailed chapters on both. Velocity tools are well covered including Anakia, which can be used to transform XML. The Velocity architecture is explained as well as ways to extend that architecture.

The examples are well thought out and give good coverage of the features of Velocity. The most interesting part of the examples is how little work it is to integrate Velocity into a well-designed framework. The author shows how Velocity fits into both Struts and Spring, demonstrating that Velocity is not meant to replace these frameworks but rather to simplify content generation in any framework. I can strongly recommend this book for anyone interested in Velocity. For anyone not interested in Velocity, the question is, why not?

I am using this book to bring myself up to speed on a project that combines Velocity with Struts. I'm working with Struts and Velocity modules built by a consulting company. Before the project, I didn't know either one. Now I am in the middle of the project and somewhat familiar with both. Most of the velocity commands I am able to figure out pretty quickly without the book, which is good because every time I try to find something ($link.setAction for example, which is needed to obtain the URL for forwarding) it's not there. Maybe I'm missing something, but if I am, it also is not identified in this book. I'm doing much better by referring to my Struts reference(Programming Jakarta Struts) and searching the web.

This is one of the only books on the subject of Velocity. Velocity is a nice technology for doing template/macro based website without having to use a heavy weight toolkit or framework.

The book is well organized and paced. I used it's information to jump start my development. Since Velocity has changed overtime this book may not be covering the latest version. However, the basic information and examples are still useful to look at. It went a bit deeper than the online document for Velocity. For that reason alone, I think getting the book is useful.

It is a good book, nevertheless be careful to try to take the Java code for your production environment, in page 189 when it is explaining about the shopping cart makes money operations with type double when should be used BigDecimal in this case.

Although the first few chapters provide a good description of the Velocity Template Language and how to drive it, I found myself progressively flipping pages after that. I also read Harrop's Pro Spring, which was much more information-dense despite being over twice the size of this book.

If you are not yet familiar with concepts like MVC, layered application design, Struts, Spring etc: ignore the previous ;-)

This is an excellent introduction to the Velocity template engine. It covers the basic use and syntax of the engine, then embedding and extending it. It's very well written and organized.

On the downside I think the graphics could have been used more effectively, and I would have liked to have seen more on the basic template syntax. Overall, however, I highly recommend this book to anyone for whom the Velocity template engine is a central part of the architecture.