code: public int getNumberOfPaths()
      {
          if(results != null)//Categorical!
              return results.length;
          else if(catAttributes != null)//Regression!
              if(regressionResults.length == 1)
                  return 1;
              else if(splittingAttribute < catAttributes.length)//Categorical
                  return catAttributes[splittingAttribute].getNumOfCategories();
              else//Numerical is always binary
                  return 2;
          return Integer.MIN_VALUE;//Not trained!
      }
docs: Returns the number of paths that this decision stump leads to. The stump may not ever
  direct a data point on some of the paths. A result of 1 path means that all data points
  will be given the same decision, and is generated when the entropy of a set is 0.0.
  <br><br>
  -1 is returned for an untrained stump
  
  @return the number of paths this decision stump has stored