public static void getDDX(String dataset, String constraintExpression, OutputStream os) throws BadConfigurationException, PPTException {
public static ServerDDS getDDX(String dataset, String constraintExpression) throws PPTException, DODSException {  return getDDX(dataset,constraintExpression, new DefaultFactory());
    public static void getDDX(String dataset,                              String constraintExpression,                              OutputStream os)            throws BadConfigurationException, PPTException {        besGetTransaction(getAPINameForDDX(), dataset, constraintExpression, os);    }