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

Seam component scope


In the previous section, we saw how it's possible to store, or cache, data by using simple Servlets. We looked at three different types of data scopes that can easily be used, local variables, HTTP session scope, and global variables.

However, Seam provides a more elegant solution that allows us to specify the scope of Seam components.

The scope of a component specifies how long the component will live, that is, how long the component is effectively cached in memory and available to the developer before it is removed from memory and is no longer available.

Within Seam, there are seven different scope contexts that can be applied to any Seam component. Ranging from the shortest scope context to the longest, these scope contexts are:

  • Stateless

  • Event

  • Page

  • Conversation

  • Session

  • Business Process

  • Application

Although we have defined the Business Process as having a shorter scope context than the Application scope, it is possible that Business Processes can last longer than Application...