The validators participate in the validation of submitted values during the request validation phase. They are responsible for checking whether the input parameter complies with the validation rules associated with the input field. The validator is expected to raise an exception and an error message is then associated with the faulty input field.

The validator is described in the XHTML file by using one of the following JSF core components:

Component Validation type
f:validateLength The input field must have a minimun/maximum length
f:validateLongRange The input field must be a number in the given range
f:validator An Ada registered or custom validator is used
f:validateRegex The input field must match the regular expression

A validator instance must implement the ASF.Validators.Validator interface. It only needs to implement the Validate procedure which gets the UI component, the faces request context and the submitted value. It must verify the value according to the validator's rule and the UI component. When the value is incorrect, it must set an error message in the UI component so that some user friendly message is reported. In case of error, it must also raise the Invalid_Value exception.

Length validator

The ASF.Validators.Texts.Length_Validator implements the validator for the <f:validateLength> XHTML validator.

Regex validator

The ASF.Validators.Texts.Regex_Validator implements the validator for the <f:validateRegex> XHTML validator.

Range validator

The ASF.Validators.Numbers defines various number oriented validators.