The J2EE™ Tutorial Second Edition

Creating a Custom Validator

If the standard validators don't perform the validation checking you need, you can easily create a custom validator to validate user input. As explained in Validation Model (page 654), there are two ways to implement validation code:

• Implement a backing bean method that performs the validation.

• Provide an implementation of the Validator interface to perform the validation.

Writing a Method to Perform Validation (page 757) explains how to implement a backing bean method to perform validation. The rest of this section explains how to implement the Validator interface.

If you choose to implement the Validator interface and you want to allow the page author to configure the validator's attributes from the page, you also ...