Matches - returns true if a value matches a provided compiled regular expression pattern.

MaxChars return true if a value contains no more than n characters.

MinChars - returns true if a value contains at least n characters.

NotBlank returns true if a value is not an empty string.

PermittedValue returns true if a value is in a list of permitted values.

Validator a type which contains a map of validation errors for our form fields.