code: public String getExpandedDRL(final String source,
                                   final Reader dsl) throws DroolsParserException {
          DefaultExpanderResolver resolver = getDefaultResolver(dsl);
          return getExpandedDRL(source,
                  resolver);
      }
docs: This will expand the DRL. useful for debugging.
  
  @param source -
  the source which use a DSL
  @param dsl -
  the DSL itself.
  @throws DroolsParserException
  If unable to expand in any way.