Book Image

Apache MyFaces 1.2 Web Application Development

Book Image

Apache MyFaces 1.2 Web Application Development

Overview of this book

Hypes and trends (such as Web 2.0) cause a change in the requirements for user interfaces every now and then. While a lot of frameworks are capable of meeting those changing requirements, it often means you as a developer need in-depth knowledge of web standards, such as XHTML and JavaScript. A framework like Apache MyFaces that hides all details of how the page is rendered at the client and at the same time offers a rich set of tools and building blocks could save you a lot of time, not only when you're building a brand new application but also when you're adapting an existing application to meet new user interface requirements.This book will teach you everything you need to know to build appealing web interfaces with Apache MyFaces and maintain your code in a pragmatic way. It describes all the steps that are involved in building a user interface with Apache MyFaces. This includes building templates and composition components with Facelets, using all sorts of specialized components from the Tomahawk, Trinidad, and Tobago component sets and adding validation with MyFaces Extensions Validator.The book uses a step-by-step approach and contains a lot of tips based on experience of the MyFaces libraries in real-world projects. Throughout the book an example scenario is used to work towards a fully functional application when the book is finished.This step-by-step guide will help you to build a fully functional and powerful application.
Table of Contents (22 chapters)
Apache MyFaces 1.2
Credits
About the Author
Acknowledgement
About the Reviewers
Preface
Trinidad Tags
Trinidad Text Keys
Default JSF Error Messages
ExtVal Default Error Messages

Creating custom error messages


With ExtVal, the error messages shown if validation fails come from different sources, as follows:

  • For validation that is derived from JPA annotations, ExtVal relies on the standard JSF validators. Hence, the error messages shown are the standard JSF error messages. The way in which standard JSF messages can be overridden is defined in the JSF standard. This is covered in the next section, Overriding standard JSF error messages.

  • The ExtVal annotations @Length, @DoubleRange, @LongRange, and @Required also rely on standard JSF mechanisms for implementing the validation. So these will lead to standard JSF error messages as well.

  • All other ExtVal annotations have their own default error messages. How to override these ExtVal messages is covered in the Overriding ExtVal default error messages section.

Overriding standard JSF error messages

Although overriding standard JSF messages is not a feature of ExtVal, we cover it briefly here for convenience. Standard JSF error...