Trying to filter a query by an attribute with @Convert is failling. I have tried to find a workaround with no success.

The case is simple (attached), there is a class with an attribute of type Set. This attribute is wanted to be saved as a String (VARCHAR) in database.

@Entity
public class MyEntity {


    private Long id;

    private Set<String> teams;

    public MyEntity() {
    }

    public MyEntity(Set<String> teams) {
        this.teams = teams;
    }

    @Id
    @GeneratedValue
    @Column(name="ID")
    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    @Convert(converter = TeamsConverter.class)
    @Column(name = "MY_ENTITY_FIELDS")
    public Set<String> getTeams() {
        return teams;
    }

    public void setTeams(Set<String> teams) {
        this.teams = teams;
    }
}

Converter translates from Set to String and viceversa

@Converter
public class TeamsConverter implements AttributeConverter<Set, String> {
    public String convertToDatabaseColumn(Set set) {
        return set == null ? null : String.join("|", set);
    }

    public Set convertToEntityAttribute(String s) {
        HashSet set = new HashSet();
        if (s != null) {
            for (String splitted : s.split("|")) {
                set.add(splitted);
            }
        }
        return set;
    }
}

I have tried 3 ways of doing this leading me to open this issue:

1. isMember

    q.where(cb.isMember("CAI", c.<Set<String>>get("teams"))); 

   //java.lang.IllegalArgumentException: unknown collection expression type [org.hibernate.jpa.criteria.path.SingularAttributePath]

1. equalToSet

      Set<String> a = new HashSet<String>();
           a.add("CAI");
           q.where(cb.equal(c.get("teams"), a));
   

   // java.lang.ClassCastException: java.lang.String cannot be cast to java.util.Set

2. equalToString

     q.where(cb.equal(c.get("teams"), "CAI")); 

   // java.lang.IllegalArgumentException: Parameter value [CAI] did not match expected type [java.util.Set (n/a)]