Infinite validation loop

Question

I have a validator for my Roo model.

When it finds an error (returns false), it works as expected.

However, when it succeeds, the controller enters an infinite loop resulting in a StackOverflowError:

at org.hibernate.validator.internal.engine.ValidatorImpl.validateConstraintsForDefaultGroup(ValidatorImpl.java:387)
at org.hibernate.validator.internal.engine.ValidatorImpl.validateConstraintsForCurrentGroup(ValidatorImpl.java:351)
at org.hibernate.validator.internal.engine.ValidatorImpl.validateInContext(ValidatorImpl.java:303)
at org.hibernate.validator.internal.engine.ValidatorImpl.validate(ValidatorImpl.java:133)
at org.hibernate.cfg.beanvalidation.BeanValidationEventListener.validate(BeanValidationEventListener.java:136)
at org.hibernate.cfg.beanvalidation.BeanValidationEventListener.onPreInsert(BeanValidationEventListener.java:94)
at org.hibernate.action.internal.EntityInsertAction.preInsert(EntityInsertAction.java:181)
at org.hibernate.action.internal.EntityInsertAction.execute(EntityInsertAction.java:81)
at org.hibernate.engine.spi.ActionQueue.execute(ActionQueue.java:377)
at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:369)
at org.hibernate.engine.spi.ActionQueue.executeActions(ActionQueue.java:286)
at org.hibernate.event.internal.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:339)
at org.hibernate.event.internal.DefaultAutoFlushEventListener.onAutoFlush(DefaultAutoFlushEventListener.java:62)
at org.hibernate.internal.SessionImpl.autoFlushIfRequired(SessionImpl.java:1205)
at org.hibernate.internal.SessionImpl.list(SessionImpl.java:1262)
at org.hibernate.internal.QueryImpl.list(QueryImpl.java:101)
at org.hibernate.ejb.QueryImpl.getSingleResult(QueryImpl.java:283)
at com.foo.domain.validate.UniqueNameValidator.isValid(UniqueNameValidator.java:30)
at com.foo.domain.validate.UniqueNameValidator.isValid(UniqueNameValidator.java:1)
at org.hibernate.validator.internal.engine.ConstraintTree.validateSingleConstraint(ConstraintTree.java:308)
at org.hibernate.validator.internal.engine.ConstraintTree.validateConstraints(ConstraintTree.java:180)
at org.hibernate.validator.internal.engine.ConstraintTree.validateConstraints(ConstraintTree.java:124)
at org.hibernate.validator.internal.metadata.core.MetaConstraint.validateConstraint(MetaConstraint.java:86)
at org.hibernate.validator.internal.engine.ValidatorImpl.validateConstraint(ValidatorImpl.java:442)
at org.hibernate.validator.internal.engine.ValidatorImpl.validateConstraintsForDefaultGroup(ValidatorImpl.java:387)

Note that the first and last lines are the same. This stack trace repeats many times before the stack overflow occurs.

My UniqueNameValidator looks like this:

public class UniqueNameValidator implements ConstraintValidator<UniqueFoo, Foo> {
  public boolean isValid(Foo value, ConstraintValidatorContext context) {
    TypedQuery<Long> q = ... // checks several conditions with other models in actual code
    return q.getSingleResult() == 0;
  }
}

My Roo MVC controller looks like this:

@RequestMapping(method = RequestMethod.POST, produces = "text/html")
public String create(@Valid Foo foo,
                     BindingResult bindingResult,
                     Model uiModel,
                     HttpServletRequest httpServletRequest) {
    if (bindingResult.hasErrors()) {
        populateCreateForm(uiModel, foo);
        return "foos/create";
    }
    uiModel.asMap().clear();

    foo.persist();

    return Session.getStoredURI("/" + encodeUrlPathSegment(foo.getId().toString(), httpServletRequest));
}

My model looks like this:

@RooJavaBean
@RooJpaActiveRecord
@UniqueName
public class Foo {
  @NotNull
  private String parentName;
  ...
}

What am I doing wrong?

Answer 1

The query in the UniqueNameValidator is causing the recursive validation.

TypedQuery<Long> q = ... 
return q.getSingleResult() == 0;

needs to be:

TypedQuery<Long> q = ...
q.setFlushMode(FlushModeType.COMMIT);
return q.getSingleResult() == 0;