code: public static int getElementCount(IMolecularFormula formula, String symbol) {
          return getElementCount(formula, formula.getBuilder().newInstance(IElement.class, symbol));
      }
docs: Occurrences of a given element in a molecular formula.
  
  @param  formula the formula
  @param  symbol  element symbol (e.g. C for carbon)
  @return         number of the times the element occurs
  @see #getElementCount(IMolecularFormula, IElement)