private void validateCyclicAliasing(String field) throws SyntaxError {
  Set<String> set=new HashSet<>();
  set.add(field);
  if (validateField(field,set)) {
    throw new SyntaxError("Field aliases lead to a cycle");
  }
}

private void validateCyclicAliasing ( String field ) throws SyntaxError { Set < String > set = new HashSet < > ( ) ; set . add ( field ) ; if ( validateField ( field , set ) ) { throw new SyntaxError ( "Field aliases lead to a cycle" ) ; } }
validate there is no cyclic referencing in the aliasing
