Hello,
Is that the way that it is intended to work? I thought I read
somewhere, though I can't find it now, that the constraints would be
checked at the end of the unit of work. I thought this would be a nice
way to allow my validation to happen in the domain layer and propagate
the violation messages to the application for them to be displayed to
the user.
The way it is currently implemented only the first constraint violation
would be reported to the user, making it unusable as a general way of
doing validation as it would require the user to submit the form, fix
the first validation error, submit the form, fix the next validation
error, ad nauseum as opposed to having all the constraint violations
checked at the end of the unit of work and reporting all violations at
once. I could duplicate the constraints in the application before
passing the parameters to the domain layer, but that just seems ugly and
was one problem I was hoping Qi4j would help me solve.
The other problem with this mechanism is that it requires a setter to be
called for any validation to be performed. The problem with this is
that it could allow invalid data to pass. For instance, in the Nameable
example that I've used elsewhere we have
public interface Nameable {
@NonEmptyString Property<String> name();
}
That non-empty string constraint is only ever going to be checked when
nameable.name().set(something) is called. If someone where to simply
create the entity and never call that setter, we'd wind up with an
invalid object in our entity store.
There are 2 ways to fix it, leave the current checks as they are and do
the constraint checks again when the unit of work completes or remove
the check on the setter and add the checks to the unit of work
completion and rely on it exclusively.
WDYT?
Rich
Rickard Öberg wrote:
> Hey,
>
> I think QI-59 is fixed now. EntityPropertiInstance simply calls
> super.set(aNewValue), which will invoke the constraints checking in
> PropertyInstance.
>
> Testcase that now works:
> @Test
> public void
> givenEntityWithConstrainedPropertyWhenInvalidPropertyValueSetThenThrowException()
> {
> UnitOfWork uow = unitOfWorkFactory.newUnitOfWork();
>
> try
> {
> TestCase testCase = uow.newEntity( TestCase.class );
>
> testCase.someProperty().set( null );
>
> uow.complete();
> fail( "Should not be allowed to set invalid property value" );
> }
> catch( Exception e )
> {
> uow.discard();
> }
> }
>
> interface TestCase
> extends EntityComposite
> {
> @NotNull Property<String> someProperty();
> }
> ---
>
> /Rickard
>
> _______________________________________________
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>
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