Execute SQL-LIKE with List attribute

I have this method on my Dao class:

  public List<E> search(String key, Object value) {
    EntityManager entityManager = getEntityManager();
    entityManager.getTransaction().begin();
    List result = entityManager.createQuery("SELECT a FROM "+clazz.getSimpleName()+" a WHERE a."+key+" LIKE '"+value+"%'").getResultList();
    entityManager.getTransaction().commit();
    entityManager.close();
    return result;
  }

the sql works fine when the attribute is @Column or a @OneToOne`, but when it’s something like that:

  @OneToMany(fetch = FetchType.EAGER, cascade=CascadeType.ALL)
  @OrderColumn
  private List<Titulo> nome;

where the class Titulo has this attributes:

  @Id
  @GeneratedValue(strategy=GenerationType.IDENTITY)
  private Integer id;

  @Column
  private String idioma;

  @Column(length=32)
  private String conteudo;

causes this error:

message: left and right hand sides of a binary logic operator were incompatible [java.util.List(org.loja.model.categoria.Categoria.nome) : string]; nested exception is org.hibernate.TypeMismatchException: left and right hand sides of a binary logic operator were incompatible [java.util.List(org.loja.model.categoria.Categoria.nome) : string]

How I can change the method to make work for both types of attributes?

Answer

I manage to solve this issue with the approach below, using java reflection to detect the type of the field trying to be queried, and using a proper sql command. Don’t know how efficient this can be; if anyone have a better solution to this, feel free to add another answer with it.

public List<E> search(String key, Object value) throws NoSuchFieldException {
    EntityManager entityManager = getEntityManager();
    entityManager.getTransaction().begin();

    List result;
    Field field = clazz.getDeclaredField(key);

    ParameterizedType listType = (ParameterizedType) field.getGenericType();
    Class<?> classElement = (Class<?>) listType.getActualTypeArguments()[0];
    String nome = classElement.getSimpleName();

    Field field2[] = classElement.getDeclaredFields();
    String attr = field2[field2.length - 1].getName();

    if(field != null) {
      if(field2 != null) {
        result = entityManager.createQuery("SELECT a FROM "+clazz.getSimpleName()+" a, "+nome+" b WHERE b."+attr+" LIKE '"+value+"%'").getResultList();
      } else {
        result = entityManager.createQuery("SELECT a FROM "+clazz.getSimpleName()+" a, "+nome+" b WHERE b LIKE '"+value+"%'").getResultList();
      }
    } else {
      result = entityManager.createQuery("SELECT a FROM "+clazz.getSimpleName()+" a WHERE a."+key+" LIKE '"+value+"%'").getResultList();
    }

    entityManager.getTransaction().commit();
    entityManager.close();
    return result;
  }

UPDATE I got one issue with the code above: in the first query (of the three in the if/else), it’s always returned all the elements of the table, almost if the LIKE was being ignored.