Hibernate Validator
Hibernate Validator 4.x is the reference implementation for JSR 303 - Bean Validation.
JSR 303 defines a metadata model and API for JavaBean validation. The default metadata source is annotations, with the ability to override and extend the meta-data through the use of XML validation descriptors. The API is not tied to a specific application tier or programming model. It is specifically not tied to either the web tier or the persistence tier, and is available for both server-side application programming, as well as rich client Swing application developer.
Bean Validation TCK
Together with the reference implementation of JSR 303 Hibernate provides also the Bean Validation TCK. You can find more information about the TCK on the Hibernate wiki.
Hibernate Validator News
- Bean Validation: restricting the metadata results
- Aug 9, 2010 9:20 AM by Emmanuel Bernard
Gunnar asked me an interesting question on Bean Validation. Instead of keeping the knowledge private, I thought it would be useful to share more wildly.
Is it possible to determine whether a given constraint is specified at field or property level using the constraint metadata API?
First off, in many case you don't need to do the distinction. Had Java support properties from the ground up, we would not have this problem (sigh).
Anyways, the answer is yes. You can fine tune what is returned from the metadata API.
PropertyDescriptor property = validator.getConstraintsForClass(Address.class) .getConstraintsForProperty("street1"); Set<ConstraintDescriptor<?>> fieldConstraints = property .findConstraints() .lookingAt(Scope.LOCAL_ELEMENT) .declaredOn(ElementType.FIELD) .getConstraintDescriptors(); Set<ConstraintDescriptor<?>> propertyConstraints = property .findConstraints() .lookingAt(Scope.LOCAL_ELEMENT) .declaredOn(ElementType.METHOD) .getConstraintDescriptors();The key here is the use of the findConstraints() fluent API. You have three ways to restrict the metadata retrieved:
- declaredOn(ElementType... types): defines where to look the constraints (METHOD, FIELD etc)
- lookingAt(Scope scope): defines whether to look for constraints hosted on superclass/interfaces (default) or not
- unorderedAndMatchingGroups(Class<?>... groups): restrict to the constraints matching a given set of groups for this element (note that the ordering of group sequences is not respected)
That's all.
