private boolean contains(RoleProxy role) {
   for (RoleProxy roleProxy : rolesSet) {
     if (roleProxy.getId().equals(role.getId())) {
       return true;
     }
   }
   return false;
 }
 private void remove(RoleProxy role) {
   for (RoleProxy roleProxy : rolesSet) {
     if (roleProxy.getId().equals(role.getId())) {
       rolesSet.remove(roleProxy);
       return;
     }
   }
 }
 @Override
 public void render(
     com.google.gwt.cell.client.Cell.Context context, RoleProxy value, SafeHtmlBuilder sb) {
   sb.append(SafeHtmlUtils.fromString(value.getName()));
 }