/**
  * Creates a new request.
  *
  * @param method the HTTP method to use
  * @param url URL to fetch the JSON from
  * @param requestData A {@link Object} to post and convert into json as the request. Null is
  *     allowed and indicates no parameters will be posted along with request.
  * @param listener Listener to receive the JSON response
  * @param errorListener Error listener, or null to ignore errors.
  */
 public JacksonRequest(
     int method,
     String url,
     Object requestData,
     Class<T> responseType,
     Response.Listener<T> listener,
     Response.ErrorListener errorListener) {
   super(
       method,
       url,
       (requestData == null) ? null : Mapper.string(requestData),
       listener,
       errorListener);
   this.responseType = responseType;
 }