code: public DecoratedKey getIndexKeyFor(ByteBuffer value)
      {
          // FIXME: this imply one column definition per index
          ByteBuffer name = columnDefs.iterator().next().name.bytes;
          return new BufferDecoratedKey(new LocalToken(baseCfs.metadata.getColumnDefinition(name).type, value), value);
      }
docs: Returns the decoratedKey for a column value
  @param value column value
  @return decorated key