Validar duplicados en un autocomplete multiple

Para validar duplicados en un autocomplete múltiple usamos

public List<Rol> completeFiltrado(String query) {
        List<Rol> suggestions = new ArrayList<>();
        List<Rol> temp = new ArrayList<>();
        try {
            Boolean found = false;
            query = query.trim();
            String field = (String) UIComponent.getCurrentComponent(FacesContext.getCurrentInstance()).getAttributes().get("field");
            temp = rolRepository.findRegex(field, query, true, new Document(field, 1));

            if (rolList.isEmpty()) {
                if (!temp.isEmpty()) {
                    suggestions = temp;
                }
            } else {
                if (!temp.isEmpty()) {

                    for (Rol r : temp) {
                        found = false;
                        for (Rol r2 : rolList) {
                            if (r.getIdrol().equals(r2.getIdrol())) {
                                found = true;
                            }
                        }
                        if (!found) {
                            suggestions.add(r);
                        }

                    }
                }

            }
            //suggestions=  rolRepository.findRegex(field,query,true,new Document(field,1));

        } catch (Exception e) {
            errorServices.errorMessage(nameOfClass(), nameOfMethod(), e.getLocalizedMessage());
        }
        return suggestions;
    }