public final class EmptyListToNull implements JsonAdapter.Factory {
    @Override
    public JsonAdapter<?> create(Type type, Set<? extends Annotation> annotations, Moshi moshi) {
        Class<?> rawType = Types.getRawType(type);
        if (checkAssignments(rawType)) {
            return null; // We don't want to decorate actual collection types.
        }

        final JsonAdapter<Object> delegate = moshi.nextAdapter(this, type, annotations);

        return new JsonAdapter<Object>() {
            @Override public Object fromJson(JsonReader reader) throws IOException {
                if (reader.peek() != BEGIN_ARRAY) {
                    return delegate.fromJson(reader);
                }

                reader.beginArray();
                reader.endArray();
                return null;
            }

            @Override public void toJson(JsonWriter writer, Object value) throws IOException {
                delegate.toJson(writer, value);
            }
        };
    }