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

Component scope


When writing web applications, we typically have several caching strategies to enable us to maintain state during the lifetime of the application.

The most common of these caching strategies are:

  • Local variables stored within a servlet

  • Data stored within a HTTP session

  • Data stored within application global caches

Note

When storing data in a global cache, developers sometimes use a database as this caching mechanism. This anti-pattern can sometimes have dramatically adverse effects as systems get bigger and the load on the database for storing and retrieving cache data increases.

These three types of caching allow us to achieve different levels of caching all the way from a fine granularity (local variables) through to coarse granularity (global variables).

Local variables

In the following simple class, we can see how we can easily cache values within a servlet.

public class SimpleServlet extends HttpServlet {
// … Unnecessary code not shown.
@Override
protected void doGet(HttpServletRequest...