I want to make a comment on the jsr-303 specification. In particular the specification of the InvalidContraint (4.2).

I think there is a problem to "rebuild the context of the failure" with InvalidContraint, in case of an object graph validation with validation of collection valued properties ( see 3.1.3). I don't see a way to retrieve the InvalidContraints for a object which is contained in a Collection.

For example if you have an rootObject Order which has a validated set of OrderItems.
In a UI you have can edit Order with OrderItems. When saving a invalid orderitem the errors of the OrderItems should be displayed. I don't know how retrieve the InvalidContraint for an OrderItem with the propertypath.

I suggest to add also reference to the validated "leaf object" , so I can retrieve the InvalidContraints for every object in a graph( even in case if they are contained in a collection). In most UI frameworks you can get a reference to the object which you are presenting (in this case an OrderItem), so getting the invalidcontraint for that object is no problem anymore if the invalidconstaint has a reference to the validated object.

Agree, I think this reference to the validated "leaf object" should be very useful.

Thanks, we will consider it.

When a bean-level constraint fails, this is the object that you get when calling javax.validation.InvalidConstraint#getValue()

When a property-level constraint fails, the JSR303 API currently does not give you access to the (child) object to which the propertyPath leads.

In the reference implementation (http://code.google.com/p/agimatec-validation/), you can access it with some extensions:
1. Create a subclass of com.agimatec.utility.validation.jsr303.InvalidConstraintImpl and add a property to hold the object

2. create a subclass of com.agimatec.utility.validation.jsr303.ConstraintValidationListener.
Method addError() gets a ValidationContext. The ValidationContext has a method getBean(), which is the object you need. Put it into the subclass of InvalidConstraintImpl

2. Subclass com.agimatec.utility.validation.jsr303.ClassValidator and overwrite method createContext(). Instanciate your subclass of ConstraintValidationListener there.

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alternatively you can use BeanValidator instead of ClassValidator. Validation returns com.agimatec.utility.validation.ValidationResults instead of a Set of InvalidContraints. The API ValidationResults offers errors-by-reason and errors-by-owner. Error instances hold the object, the reason and the propertyName.