@NotNull private String addUniqueField(@NotNull String name) { List<String> existNames = fieldNames.get(name); if (existNames == null) { existNames = new LinkedList<String>(); fieldNames.put(name, existNames); } String suffix = existNames.isEmpty() ? "" : "$" + existNames.size(); String newName = name + suffix; existNames.add(newName); return newName; }