Question

I have a problem with using Conjunctions and Disjunctions. My program receives an arbitrary number of filter elements (each representing a Criterion) from the ui and is intended to chain together them as an AND or OR.

So for example I can have 3 elements like this (I represent a Criterion with a letter):

a OR b AND c

My code looks like this:

    // ...
    Criteria rootCriteria = createCriteria(entityClass);
    Conjunction conjunction = Restrictions.conjunction();
    Disjunction disjunction = Restrictions.disjunction();
    boolean isFirst = true;
    for (InternalFilterElement element : elements) {
        if (isFirst) {
            isFirst = false;
            rootCriteria.add(createCriterion(element.getFilterRelation(), element.getValue()));
        } else if (InternalFilterOperand.AND.equals(element.getInternalFilterOperand())) {
            addCriterionToJunction(conjunction, element);
        } else {
            addCriterionToJunction(disjunction, element);
        }
    }
    rootCriteria.add(disjunction);
    rootCriteria.add(conjunction);
    // ...

My problem is that I always get a AND b AND c and some unnecessary parentheses.

What I really wish to know is that I am using the wrong tool for this task or not? How can I mix AND and OR operators?

edit

InternalFilterOperand is basically an enum containing OR and AND

addCriterionToJunction just adds a Criterion to the Junction based on the relation (<, >, …) and the value. It does not have any side effects.

Answer 1

By using the following code, you mix AND and OR operators in Hibernate:

    Criteria rootCriteria = createCriteria(entityClass);
    rootCriteria.add(Restrictions.or(
            Restrictions.eq("a","a"),
            Restrictions.and(
                    Restrictions.eq("b","b"),
                    Restrictions.eq("c","c")
            )
    ));

This example results in the following output: a=a OR b=b AND c=c without the parenthesis you would get with conjunction and disjunction.