content: /*
   * Copyright 2017 Google Inc. All rights reserved.
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package com.example.networksecurity.data.remote;
  
  
  import com.android.volley.AuthFailureError;
  import com.android.volley.NetworkResponse;
  import com.android.volley.ParseError;
  import com.android.volley.Request;
  import com.android.volley.Response;
  import com.android.volley.toolbox.HttpHeaderParser;
  import com.google.gson.Gson;
  import com.google.gson.JsonSyntaxException;
  
  import java.io.UnsupportedEncodingException;
  import java.util.Map;
  
  /**
   * A Volley Request for Gson.
   * Code from https://developer.android.com/training/volley/request-custom.html
   *
   * @param <T>
   */
  public class GsonRequest<T> extends Request<T> {
      private final Gson gson = new Gson();
      private final Class<T> clazz;
      private final Map<String, String> headers;
      private final Response.Listener<T> listener;
  
      /**
       * Make a GET request and return a parsed object from JSON.
       *
       * @param url     URL of the request to make
       * @param clazz   Relevant class object, for Gson's reflection
       * @param headers Map of request headers
       */
      public GsonRequest(String url, Class<T> clazz, Map<String, String> headers,
                         Response.Listener<T> listener, Response.ErrorListener errorListener) {
          super(Method.GET, url, errorListener);
          this.clazz = clazz;
          this.headers = headers;
          this.listener = listener;
      }
  
      @Override
      public Map<String, String> getHeaders() throws AuthFailureError {
          return headers != null ? headers : super.getHeaders();
      }
  
      @Override
      protected void deliverResponse(T response) {
          listener.onResponse(response);
      }
  
      @Override
      protected Response<T> parseNetworkResponse(NetworkResponse response) {
          try {
              String json = new String(
                      response.data,
                      HttpHeaderParser.parseCharset(response.headers));
              return Response.success(
                      gson.fromJson(json, clazz),
                      HttpHeaderParser.parseCacheHeaders(response));
          } catch (UnsupportedEncodingException e) {
              return Response.error(new ParseError(e));
          } catch (JsonSyntaxException e) {
              return Response.error(new ParseError(e));
          }
      }
  }