Provide custom Validator for @Size

Question

How could I provide a custom validator implementation for a built-in constraint like @Size? in a JavaEE6 JSF Web Application

Answer 1

Implement a ConstraintValidator<MyType, Size>, register it via an XML based constraint mapping:

<constraint-mappings
    xmlns="http://jboss.org/xml/ns/javax/validation/mapping" version="1.1">

    <constraint-definition annotation="javax.validation.constraints.Size">
        <validated-by include-existing-validators="false">
            <value>org.mycompany.MySizeValidator</value>
        </validated-by>
    </constraint-definition>
</constraint-mappings>

and add this mapping to META-INF/validation.xml:

<validation-config
    xmlns="http://jboss.org/xml/ns/javax/validation/configuration" version="1.1">

    <constraint-mapping>path/to/mapping.xml</constraint-mapping>
</validation-config>

You can learn more in the Hibernate Validator reference guide.