Create a JPA Criteria fully dynamically

Question

Usually I\'m a Hibernate user and for my new project we use JPA 2.0.

My DAO receives a Container with a generic.

public class Container {
          


        

Answer 1

As long as your T is Comparable (it's required for greaterThan), you should be able to do something like the following:

public class Container<T extends Comparable<T>> { 
    ...
    public <R> Predicate toPredicate(CriteriaBuilder cb, Root<R> root) {
        ...
        if (">".equals(operation) {
            return cb.greaterThan(root.<T>get(fieldId), value);
        } 
        ...
    }
    ...
}