class DisplayData implements Serializable {

  @Override
  public String toString() {
    StringBuilder builder = new StringBuilder();
    boolean isFirstLine = true;
    for (Item entry : entries.values()) {
      if (isFirstLine) {
        isFirstLine = false;
      } else {
        builder.append("\n");
      }

      builder.append(entry);
    }

    return builder.toString();
  }

  private  DisplayData(Map<Identifier, Item> entries);

}