Case insensitive search with Predicate and Criteria API

Question

I have currently implemented a dynamic query builder that works perfectly if my query conditions are spelled correctly. Since this might not be always the case I need a solution that is flexible enough to take any variation of the condition, primarily supporting case insensitivity.

Current specification's toPredicate method override code looks like this:

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

    Path<String> username = root.get("username");
    Path<String> agentCode = root.get("agentCode");
    Path<EntityStatus> status = root.get("status");
    Path<String> firstname = root.get("firstName");
    Path<String> lastname = root.get("lastName");
    Path<String> email = root.get("eMail");


if(criteria.getUsername()!=null && !criteria.getUsername().isEmpty()) {
      predicates.add(cb.equal(username, criteria.getUsername()));
    }

    if(criteria.getAgentCode()!=null && !criteria.getAgentCode().isEmpty()) {
      predicates.add(cb.equal(agentCode, criteria.getAgentCode()));
    }

    if(criteria.getFirstName()!=null && !criteria.getFirstName().isEmpty()) {
      predicates.add(cb.like(firstname, "%"+criteria.getFirstName()+"%"));
    }

    if(criteria.getLastName()!=null && !criteria.getLastName().isEmpty()) {
      predicates.add(cb.equal(lastname, criteria.getLastName()));
    }

    if(criteria.getEMail()!=null && !criteria.getEMail().isEmpty()) {
      predicates.add(cb.equal(email, criteria.getEMail()));
    }

    if(criteria.getStatus()!=null) {
      predicates.add(cb.equal(status, criteria.getStatus()));
    }

    return cb.and(predicates.toArray(new Predicate[predicates.size()]));
  }

And my repository interface that is being called from the service layer looks like this.

public interface UserRepo extends PagingAndSortingRepository<User, Long> {
     List<User> findAll(Specification spec);
}

Answer 1

As @Nikolas Charalambidis has suggested, I've used a variation of his answer that is suitable for my exact implementation. The answer required modifying only predacate.add() lines. With this answer the solution is flexible enough to support both case insensitivity as well as partial input.

predicates.add(cb.like(cb.lower(email), "%"+criteria.getEMail().toLowerCase()+"%"));