code: private String expandString() {
          final FastStringBuffer fsb = new FastStringBuffer(FastStringBuffer.SMALL);
          try {
              final INodeReadTrx rtx = createRtxAndMove();
              final FilterAxis axis = new FilterAxis(new DescendantAxis(rtx), rtx, new TextFilter(rtx));
  
              while (axis.hasNext()) {
                  if (rtx.getNode().getKind() == TEXT) {
                      fsb.append(rtx.getValueOfCurrentNode());
                  }
                  axis.next();
              }
              rtx.close();
          } catch (final TTException exc) {
              LOGGER.error(exc.toString());
          }
          return fsb.condense().toString();
      }
docs: Filter text nodes.
  
  @return concatenated String of text treeData values.