private void appendCombo(final RequestBuilder builder) {
   if (SecurityType.COMBO.equals(contract.getSecurityType())) {
     builder.append(contract.getComboLegs().size());
     for (final ComboLeg comboLeg : contract.getComboLegs()) {
       builder.append(comboLeg.getContractId());
       builder.append(comboLeg.getRatio());
       builder.append(comboLeg.getOrderAction().getAbbreviation());
       builder.append(comboLeg.getExchange());
     }
   }
 }
 private void appendContract(final RequestBuilder builder) {
   if (Feature.MARKET_DATA_REQUEST_BY_CONTRACT_ID.isSupportedByVersion(
       getServerCurrentVersion())) {
     builder.append(contract.getId());
   }
   builder.append(contract.getSymbol());
   builder.append(contract.getSecurityType().getAbbreviation());
   builder.append(contract.getExpiry());
   builder.append(contract.getStrike());
   builder.append(contract.getOptionRight().getName());
   builder.append(contract.getMultiplier());
   builder.append(contract.getExchange());
   builder.append(contract.getPrimaryExchange());
   builder.append(contract.getCurrencyCode());
   builder.append(contract.getLocalSymbol());
 }