code: protected List<ColumnDef> getIndexes() throws IOException
      {
          CfDef cfdef = getCfInfo(loadSignature).cfDef;
          List<ColumnDef> indexes = new ArrayList<ColumnDef>();
          for (ColumnDef cdef : cfdef.column_metadata)
          {
              if (cdef.index_type != null)
                  indexes.add(cdef);
          }
          return indexes;
      }
docs: get a list of columns with defined index