Persistance's CriteriaBuilder - check if greater than 0

Question

I gave up trying to figure it out so I ask here :) my goal is to filter some data in database query by CriteriaBuilder. Each Client has fields like howMuchOrders and orderTotalValue.

Here I try to check if my given atLeastAverageValue is lower than averageTotalValueExpression(calculated by dividing orderTotalValue by howMuchOrders). At very begining I need to check if my atLeastAverageValue is not null. Otherwise I do not want to add predicate to list of executed predicates with query.

Everything works fine until root.get("orderCount") gives zero (which is possible) and it throws org.springframework.dao.DataIntegrityViolationException. I could catch and handle this exception, but it is not the way i like to do it. Firstly I'd like to check if value in root.get("orderCount") is not null. If it is not - calculate and add prediacte to predicates list. Otherwise do nothing.

private void addMaxAveragePredicate(BigDecimal atLeastAverageValue, List<Predicate> predicates, CriteriaBuilder builder, Root<?> root) {
    if (atLeastAverageValue!=null) {
            Expression averageTotalValueExpression = builder.quot(root.get("orderCount"), root.get("orderTotalValue")).as(BigDecimal.class);
            predicates.add(builder.lessThanOrEqualTo(averageTotalValueExpression, atLeastAverageValue));

    }
}

Can anyone help?

Answer 1

Found the solution! I was not able to find out if the value is greater than 0 like in if statement, but I imagined how would the sql query look. I just needed to check if orderCount > 0 and orderValue/order in logical AND :) looks like this:

predicates.add(builder.and(builder.greaterThan(root.get("orderCount"), 0), 
builder.lessThanOrEqualTo(exQuot, attValue)));

I just needed some time :)