public Namespace(PrincipalUser creator,String qualifier,PrincipalUser owner,Set<PrincipalUser> users){
  super(creator);
  setQualifier(qualifier);
  setOwner(owner);
  if (users != null && !users.isEmpty()) {
    setUsers(users);
  }
  addUser(owner);
}

public Namespace ( PrincipalUser creator , String qualifier , PrincipalUser owner , Set < PrincipalUser > users ) { super ( creator ) ; setQualifier ( qualifier ) ; setOwner ( owner ) ; if ( users != null && ! users . isEmpty ( ) ) { setUsers ( users ) ; } addUser ( owner ) ; }
creates a new namespace object .
