code: @Override
      public void setTargetHistoryToken(final String targetHistoryToken) {
          this.targetHistoryToken = targetHistoryToken;
          if (targetHistoryToken != null) {
              final String hash = History.encodeHistoryToken(targetHistoryToken);
              getAnchorElement().setHref("#" + hash);
          }
      }
docs: Set the target history token for the widget. Note, that you should use either {@link #setTargetHistoryToken(String)}
  or {@link #setHref(String)}, but not both as {@link #setHref(String)} resets the target history token.
  @param targetHistoryToken String target history token of the widget