code: @Override
      public DescriptorValue calculate(IAtomContainer container) {
          if (order.equals("")) {
              int bondCount = 0;
              for (IBond bond : container.bonds()) {
                  boolean hasHydrogen = false;
                  for (int i = 0; i < bond.getAtomCount(); i++) {
                      if (bond.getAtom(i).getSymbol().equals("H")) {
                          hasHydrogen = true;
                          break;
                      }
                  }
                  if (!hasHydrogen) bondCount++;
  
              }
              return new DescriptorValue(getSpecification(), getParameterNames(), getParameters(), new IntegerResult(
                      bondCount), getDescriptorNames(), null);
          }
  
          int bondCount = 0;
          for (IBond bond : container.bonds()) {
              if (bondMatch(bond.getOrder(), order)) {
                  bondCount += 1;
              }
          }
  
          return new DescriptorValue(getSpecification(), getParameterNames(), getParameters(), new IntegerResult(
                  bondCount), getDescriptorNames());
      }
docs: This method calculate the number of bonds of a given type in an atomContainer
  
  @param  container  AtomContainer
  @return            The number of bonds of a certain type.