MyFaces Extensions Validator

Validation is an important part of every business application. Therefore JavaServer Faces (JSF) provides a specific phase for it that covers the needs of many web applications. However as time passed, new features and specifications were introduced by the Java Community Process (JCP). One feature that became an important part of Java software development was metadata via annotations. The most important reason to use metadata-based validation is to prevent duplication of code. In the past it was common use to repeat all sorts of validation in the View layer of a project. With metadata-based validation, this is no longer necessary.

MyFaces ExtVal allows to validate

• Bean-Validation (JSR 303) constraints (integration of any JSR 303 implementation for all JSF versions)
• Custom constraints
• Existing metadata (e.g. metadata of JPA annotations)
• ExtVal constraints
  • Simple constraints
  • Constraints for cross-validation

Main features of ExtVal

• Platform for JSF based validation
• Cross-component validation (including cross-entity validation)
• JPA Support (validation based on JPA annotations)
• Extensible (e.g. custom annotations, error messages and much more!)
• Support for client-side validation
• Validation exception interception
• Zero configuration (just optional)
• Bean-Validation (JSR 303) Support (3rd release and higher)