class BookSellerAgentCapabilities extends SemanticCapabilities {
  protected KBase setupKbase() {
    FilterKBase kb = (FilterKBase) super.setupKbase();
    
    // 1. Assertion filter to handle the not_for_sale predicate
    kb.addKBAssertFilter(new KBAssertFilterAdapter("(B ??myself (not (for_sale ??isbn ??seller)))") {
      public Formula doApply(Formula formula, MatchResult match) {
        Term isbn = match.term("isbn");
        myKBase.retractFormula(ISBN_FORMULA.instantiate("isbn", isbn));
        myKBase.retractFormula(TITLE_FORMULA.instantiate("isbn", isbn));
        myKBase.retractFormula(SELLING_PRICE_FORMULA.instantiate("isbn", isbn));
        myKBase.retractFormula(SELLING_DELAY_FORMULA.instantiate("isbn", isbn));
        ...
        return new TrueNode();
      }
    });

    // 2. Assertion filter to handle the selling_price predicate
    kb.addKBAssertFilter(new KBAssertFilterAdapter("(B ??myself (selling_price ??isbn ??price ??seller))") {
      public Formula doApply(Formula formula, MatchResult match) {
        Term isbn = match.term("isbn");
        myKBase.retractFormula(SELLING_PRICE_FORMULA.instantiate("isbn", isbn));
        return formula;
      }
    });

    // 3. Query filter to check if a string is a substring of another one
    kb.addKBQueryFilter(new KBQueryFilterAdapter("(B ??myself (zsubstr ??str ??substr))") {
      public MatchResult doApply(Formula formula, MatchResult match) {
        // The parameters of the zsubstr predicate must be instantiated
        String str = ((Constant)match.term("str")).stringValue();
        String substr = ((Constant)match.term("substr")).stringValue();
        return ( str.indexOf(substr) != -1 ) ? match : null;
      }
    });

    return kb;
  }
}