code: public static int getBondCount(IChemSequence sequence) {
          int count = 0;
          for (int i = 0; i < sequence.getChemModelCount(); i++) {
              count += ChemModelManipulator.getBondCount(sequence.getChemModel(i));
          }
          return count;
      }
docs: Get the total number of bonds inside an IChemSequence.
  
  @param sequence   The IChemSequence object.
  @return           The number of Bond objects inside.