protected Precondition makePrecondition(final InputPort port,int portIndex){
  return makePrecondition(port);
}

protected Precondition makePrecondition ( final InputPort port , int portIndex ) { return makePrecondition ( port ) ; }
subclasses might override this method in order to specify preconditions dependent on the number of port . for example when a parameter lists the input types , etc . . .
