This month, I'll round out the MVC triptych with a discussion of Grails views. Views (as you might guess) are stored in the grails-app/views directory. But there's much more to the view story than the intuitively obvious directory name. I'll talk about Groovy Server Pages (GSP) and give you pointers to many alternative view options. You'll learn about the standard Grails tag libraries (TagLibs) and find out how easy it is to create your own TagLib. You'll see how to fight the ongoing battle for DRYness (see Resources) by factoring common fragments of GSP code into their own partial templates. Finally, you'll learn how to tweak the default templates for scaffolded views, thereby balancing the convenience of automatically created views with the desire to move beyond a Grails application's default look-and-feel.

Many-to-many (m:m) relationships can be tricky to deal with in a Web application. In this installment of Mastering Grails , Scott Davis shows you how to implement m:m relationships in Grails successfully. See how they're handled by the Grails Object Relational Mapping (GORM) API and the back-end database. Also find out how a bit of Ajax (Asynchronous JavaScript + XML) can streamline the user interface.

Why would Bob McWhirter and James Strachan create a new scripting language? Why would they call it Groovy? More importantly, what features would enable Groovy to succeed when others are already entrenched? Let's answer the third question with a look at Groovy's features.

One pattern that shows up repeatedly is creating a Many-to-Many relationship using a mapping class. In Rails, the hasMany/through directive provides this functionality. Grails doesn't have an explicit hasMany/through statement like Rails. Rather, Many-to-Many relationships are created implicitly by GORM via your domain classes.

This article outlines my first attempt using Grails, though I already had experience with Groovy, the JVM compatible dynamic language, the Spring framework, Hibernate, and of course, Java.

The number of cell phone users worldwide is at 3.3 billion and rising, and Internet access from mobile phones is on a rapidly upward trajectory. Developing for the mobile Web has its unique demands. In this Mastering Grails installment, Scott Davis shows you how to make your Grails applications mobile phone friendly.

In this Mastering Grails installment, Scott Davis explores the various ways that Grails can use database tables that don't conform to the Grails naming standard. If you have Java™ classes that already map to your legacy databases, Grails allows you to use them unchanged. You'll see examples that use Hibernate HBM files and Enterprise JavaBeans 3 annotations with legacy Java classes.

Do you want to build your Web sites faster and cheaper, but still leverage industrial-strength technology? You can do just that using Grails and Apache Geronimo. Grails leverages the power of the dynamic language Groovy to accelerate your development. However, it runs on the Java Virtual Machine and leverages proven Java technologies. This makes it easy to take your Grails application to the next level by deploying it to Apache Geronimo, the premiere open source Java EE V5-certified application server. In this article, you will see how easy Grails can make Web development and how easy Geronimo can make Grails deployment. You will also see how a Grails application can leverage the resources and services provided by Geronimo.

Building a Web site is a study in event-driven, reactive development. Your application sits idle, anxiously waiting for the user to send in a request. It passes back the response and then goes back to sleep until the next call. In addition to the traditional Web life cycle of HTTP requests and responses, Grails provides a number of custom touch points where you can tap into the event model and provide behavior of your own. In this article, you'll discover the myriad of events being thrown in during the build process. You'll customize the startup and shutdown of your application. And finally, you'll explore the life cycle events of Grails domain classes.

The Grails framework greatly simplifies the task of building a Java web application. This article illustrates one approach to integrating a Flex application with a Java server application using Grails. The sample application for this article is a simple Flex search application, but the principles shown here still apply for building more complex applications