public Collection<? extends Object> search(Object obj, Connection conn) {
        if(obj instanceof Aluno){
            return this.listAll(this.createSelectAlunoHistoricoCmd((Aluno)obj), conn);
        }
        else if(obj instanceof Turma){
            return this.listAll(this.createSelectAlunosTurmaCmd((Turma)obj), conn);
        }
        
        return new ArrayList<Object>();
    }