Question

Here is my function:

private boolean CheckPassword(String type, String login, String passwordHash) {
    EntityManagerFactory entityManagerFactory 
            = Persistence.createEntityManagerFactory("kwestionariuszFor" + type);
    EntityManager entityManager 
            = entityManagerFactory.createEntityManager();
    type = type.substring(0, 1).toUpperCase() + type.substring(1, type.length());
    List<Object> entities 
            = entityManager.createNamedQuery(type + ".findByLogin").setParameter("login", login).getResultList();
    if (passwordHash.equals(entities.get(0).Password)) {
        return true;
    }
    else {
        return false;
    }
}

The Java doesn’t “know” that there IS Password column in any of the tables. I was thinking that the way to tell it so may look like this:

List<type.toClass()>

or something… is there any way to achieve what I want? I don’t want to create if, after if, after if… -_-‘

Answer 1

You must create a common type for all of your classes that represent database tables.

Like this:

public abstract class PasswordObject {
    private String password;

    public PasswordObject(String password) {
        this.password = password;
    }

    public String getPassword() {
        return password;
    }
}

I don’t know if the method createNamedQuery would be able to return a List<PassowrdObject>, but if not, you can just cast it like this (as long as it’s safe to do so, which you can only tell by the way you use it):

PasswordObject po = (PasswordObject) entities.get(0);
String password = po.getPassword();