public Builder add(Term term){
  return add(term,positions.isEmpty() ? 0 : 1 + positions.get(positions.size() - 1));
}

public Builder add ( Term term ) { return add ( term , positions . isEmpty ( ) ? 0 : 1 + positions . get ( positions . size ( ) - 1 ) ) ; }
adds a term to the end of the query phrase . the relative position of the term is the one immediately after the last term added .
