@Override
  protected void validateRequest() {
    if (!params().containsKey("input")) {
      throw new IllegalArgumentException("Request must contain 'input'.");
    }
  }
A <a
href="https://developers.google.com/places/web-service/query#query_autocomplete_requests">Query
Autocomplete</a> request.
src/main/java/com/google/maps/QueryAutocompleteRequest.java