Book Image

Seam 2.x Web Development

Book Image

Seam 2.x Web Development

Overview of this book

The Seam framework from JBoss allows developers to use JSF, Facelets, EJB, and JPA to write conversational web applications. But you will first have to learn how these standard technologies are integrated using Seam and how they can be built upon using additional Seam components. If you need to build a Java web application fast, but don't have time to learn all these complex features, then this book is for you. The book provides a practical approach to developing Seam applications highlighting good development practices. It provides a complete walk through to develop Web applications using Seam, Facelets, and RichFaces and explains how to deploy them to the JBoss Application Server. You can start using key aspects of the Seam framework immediately because this book builds on them chapter by chapter, finally ending with details of enterprise functionality such as PDF report generation and event frameworks. First, the book introduces you to the fundamentals of Seam applications, describing topics such as Injection, Outjection and Bijection. You will understand the Facelets framework, AJAX, database persistence, and advanced Seam concepts through the many examples in the book. The book takes a practical approach throughout to describing the technologies and tools involved. You will add functionality to Seam applications after you learn how to use the Seam Generator RAD tools and how to customize and fully test application functionality. Hints and tips are provided along the way of how to use Seam and the JBoss Application Server.
Table of Contents (17 chapters)
Seam 2.x Web Development
Credits
About the author
About the reviewers
Preface

Persisting Java entities to the database


Now that we've seen how SeamGen helps us to configure persistence in our applications, let's take a look at how we can persist Java entities into a relational database.

The Seam Framework makes persisting entities or POJOs to relational databases much easier than executing SQL directly against the database. For an object to persist as an entity, there are several requirements that the POJO must enforce, as defined in the Java EE tutorial (http://java.sun.com/javaee/5/docs/tutorial/doc/bnbqa.html).

  • The class must be annotated with the @Entity annotation, as defined in the javax.persistence.Entity class.

  • The class must not have a private no-argument constructor. If you have not explicitly defined a no-argument constructor in a class, then the class will inherently have one.

  • The class must not be declared as final.

  • Entity properties must be accessible via getter and setter methods.

Let's take a look at a simple Java class that can be persisted to the database...