core:

import EDU.neu.ccs.demeter.*;
add: class SummingVisitor extends UniversalVisitor {
  protected int total;
  public int get_total() (@ return total; @)
  public void set_total(int new_total)
    (@ total = new_total; @)
  public constructor SummingVisitor(int total) (@
    super();
    set_total(total);
  @)
  public static SummingVisitor parse(java.io.Reader in)
    throws ParseException
  (@ return new Parser(in)._SummingVisitor(); @)
  public static SummingVisitor parse(java.io.InputStream in)
    throws ParseException
  (@ return new Parser(in)._SummingVisitor(); @)
  public static SummingVisitor parse(String s) (@
    try { return parse(new java.io.StringReader(s)); }
    catch (ParseException e) {
      throw new RuntimeException(e.toString());
    }
  @)
  public constructor SummingVisitor() (@ total = 0; @)
  public void before(Quantity host) (@ System.out.println("sum " + total); 
	total = total + host.get_number().intValue(); @)
  int get_return_val() (@ return total ; @)
(@  void universal_trv0_bef(UniversalVisitor _v_) {
    super.universal_trv0_bef(_v_);
  }
@)
(@  void universal_trv0_aft(UniversalVisitor _v_) {
    super.universal_trv0_aft(_v_);
  }
@)
(@  void universal_trv0(UniversalVisitor _v_) {
    universal_trv0_bef(_v_);
    super.universal_trv0(_v_);
    universal_trv0_aft(_v_);
  }
@)
}