protected void addMembers(List<RelationMember> newMembers,boolean atBeginning){
  if (atBeginning) {
    members.addAll(0,newMembers);
  }
 else {
    members.addAll(newMembers);
  }
}

protected void addMembers ( List < RelationMember > newMembers , boolean atBeginning ) { if ( atBeginning ) { members . addAll ( 0 , newMembers ) ; } else { members . addAll ( newMembers ) ; } }
adds multiple elements to the relation in the order in which they appear in the list . they can be either prepended or appended to the existing nodes .
