code: public SortDirection getSortDirection(String sortExpression) {
          Sort term = findSort(sortExpression);
          return term == null ? SortDirection.NONE : term.getDirection();
      }
docs: Get the {@link SortDirection} for a {@link Sort} given a sort expression.
  
  @param sortExpression the sort expression used to locate a {@link Sort} object.
  @return a {@link Sort}'s {@link SortDirection} if one is found whose <code>sortExpression</code>
  property matches the given <code>sortExpression</code>.  <code>null</code> otherwise.