根据其他条件向条件添加多个参数

Question

I want to create a Hibernate query with criteria that dynamically changes based on further conditions

Example

First, create criteria.

if (condition 1 applies) {add another argument to the criteria}

if (condition 2 applies) {add another argument to the criteria} else {add another argument to the criteria}

Finally, get the result in a list.

I have this snippet so far.

Unfortunately, I haven't got provided with a test environment so I cannot test what happens if I put another query.where command after the first one. I'd like to use multiple where clauses, first always use one as a base, then add more if certain conditions met.

session = HibernateUtil.openSession();

CriteriaBuilder cb = session.getCriteriaBuilder();
CriteriaQuery<MyClass> query = cb
        .createQuery(MyClass.class);

Root<MyClass> root = query.from(MyClass.class);

query.select(root);
query.where(
        cb.and(
                cb.equal(root.get("dataPointId"), container.getDataPointId()),
                cb.equal(root.get("datapointSubNumber"), subnumber)
        )
);

I want to specifiy more where clauses based on conditions and get the result as a List<MyClass> .

Answer 1

You can use CriteriaBuilder and pass an array of Predicates to it. While adding the predicates you can have your if-else based on conditions to build a dynamic list. You can have your complex logic and build predicates array accordingly.

Something like this:

List<Predicate> predicates = new ArrayList<Predicate>();

if ( <some condition> ) {
    predicates.add(criteriaBuilder.like(<your query condition>));
} else {
    predicates.add(criteriaBuilder.equal(<your query condition>));
}

And at last:

query.where(criteriaBuilder.and(predicates.toArray()));