thejavajar

Google App Engine’s support of Java was a long awaited, highly demanded feature of the service back when I first started messing around with original, Python version a little over a year ago. The excitement that App Engine brought to developers was echoed by the overwhelming request for Java support. Over the past 10 days I have created a few sample applications locally to give it a test. I went the App Engine Eclipse plugin route to get things started. It is a really nice plugin that delivers what you would expect from Google. Once installed, you can create a project and have it running in under a minute.

Once I got familiar with what I was working with, I decided to turn this sample application into a simple Spring Web Flow 2 demo. That is where development stopped. Unfortunately, there are a lot of JVM features/classes that are not accessible on App Engine that Web Flow 2 (and 3rd party libraries) needs for binding and flow execution support. Nothing against Google or SpringSource, I just did not get what I wanted.

Fortunately, I created a new sample app that is based on Groovy’s Groovlet technology and things were moving forward again. Just configure the GroovyServlet in your web.xml file and away you go. My next experiment will be to work with Grails on App Engine via the Grails App Engine plugin.

Overall, App Engine is great. It is really easy to use and the application dashboard features are amazing. Access to application and admin log files in a nice HTML based presentation. Quota detail that explains bandwidth, CPU and datastore utilization along with access to different versions of your application.  You can even grant access to other developers for collaboration efforts. All features you normally do not get from your company’s “Enterprise” admin group.

On a side note, Vladimir Vivien and I will be discussing Google App Engine at the Tampa JUG on August 25th, 2009.

Spring Web Flow 2 Web Development is a great read for developers who want to take a hands-on approach to learning a great technology. By following and working with the examples, you can experience the basic principles of Spring Web Flow 2 and how it integrates with JSF, Spring Security and AJAX. This book is great for Java developers who are already using the core Spring Framework and now want to involve Spring in the presentation tier of a Web application.

Within the first few chapters, the authors present a good overview of Spring Web Flow 2. Chapter 2 starts with the installation of Spring Web Flow 2 and some help with running the examples packaged within the distribution. Chapter 2 also goes over putting together a development environment that is based on some pretty standard open source technologies like Ant, Maven, Ivy, Eclipse (Spring IDE) and NetBeans. The “Support for Developers” section of chapter 2 is a great feature of this book because if you are not already familiar with the aforementioned technologies, you get exposure to some great open source development tools. After learning a little more about how everything works together, the authors throw in a little JPA and by the end of chapter 2, you have completed your first example.

The focus of chapter 4 is Spring Faces. In my opinion, if you are going to work with JSF, focus on this chapter because Web Flow 2 is what is missing from JSF. I am not a big fan of some of the JSF implementations I have used in the past, but Web Flow 2 makes working with JSF and Facelets a bit nicer and the Spring Faces tag library is very helpful. Combine chapter 4 with chapter 5’s sections on Subflows and AJAX and you will have a good foundation for creating rich Web applications with Web Flow 2.

Chapter 6 illustrates Spring Web Flow 2’s testing support. A very important part of the development process is testing. Too many developers overlook the importance of testing especially when it comes to Web applications. Web Flow 2 comes with great testing support and as the book points out, testing support is part of the framework rather than an after-thought for developers.

Some Web applications require some level of security and most enterprise Web applications have to incorporate support for authentication and multiple levels of authorization. Chapter 7 discusses the integration of Web Flow 2 with Spring Security, formerly Acegi Security. This chapter provides a great high level view of Spring Security configuration and how to lock down access to parts of a Web page and even method level security.

Overall I enjoyed reading this book and learning Spring Web Flow 2. The authors, Markus Stäuble and Sven Lüppken, did a great job in presenting the core concepts of the technology in only 200+ pages. Prior to reading the book, I had little knowledge of the technology, but now I would be comfortable working on a project that is utilizing Spring Web Flow 2. More information about the book and authors can be found at www.packtpub.com.

Last night I got to spend a little time with a book I will be reviewing, Spring Web Flow 2 Web Development. I had a few other things going on last night, but I read through the table of contents and the preface to get an idea of what to expect. I think that Spring Web Flow is a great technology and I look forward to getting more intimate with the subject. I am not familiar with the authors, Sven Lüppken and Markus Stäuble, but I have read a little about them at the Packt Publishing Web site and I am excited to see how they present a great technology like Spring Web Flow 2. Chapter 4 is available as a sample chapter along with the code from the book and a few other resources at the publisher’s Web site.