private int deriveInstanceId(String name,int id){
  if (id == 0) {
    return 0;
  }
 else {
    final int prime=31;
    int result=1;
    result=(prime * result) + name.hashCode();
    result=(prime * result) + id;
    return result;
  }
}

private int deriveInstanceId ( String name , int id ) { if ( id == 0 ) { return 0 ; } else { final int prime = 31 ; int result = 1 ; result = ( prime * result ) + name . hashCode ( ) ; result = ( prime * result ) + id ; return result ; } }
calculates an instance id from a pair of a name and a definition id .
