Service Generator

ServiceGenerator

import android.text.TextUtils;

import org.jetbrains.annotations.NotNull;

import java.io.IOException;
import java.util.concurrent.TimeUnit;

import okhttp3.Interceptor;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;
import okhttp3.logging.HttpLoggingInterceptor;
import retrofit2.Retrofit;
import retrofit2.converter.gson.GsonConverterFactory;

public class ServiceGenerator {

    public static final String API_BASE_URL = "https://someurl.com";

    private static OkHttpClient.Builder httpClient = new OkHttpClient.Builder();

    private static Retrofit.Builder builder =
            new Retrofit.Builder()
                    .baseUrl(API_BASE_URL)
                    .addConverterFactory(GsonConverterFactory.create());

    private static Retrofit retrofit = builder.build();

   public static <S> S createService(Class<S> serviceClass) {
        return createService(serviceClass, null, null);
    }

    public static <S> S createService(
            Class<S> serviceClass, String username, String authtoken) {
        if (!TextUtils.isEmpty(username)
                && !TextUtils.isEmpty(authtoken)) {
            return createServices(serviceClass,username, authtoken);
        }

        return createServices(serviceClass,null, null);
    }

    public static <S> S createServices(
            Class<S> serviceClass, final String username , final String authToken) {

        HttpLoggingInterceptor logging = new HttpLoggingInterceptor();
        logging.setLevel(HttpLoggingInterceptor.Level.BODY);

        httpClient.readTimeout(5000, TimeUnit.SECONDS);
        httpClient .callTimeout(5000, TimeUnit.SECONDS);
        httpClient  .addInterceptor(logging);
        if (!TextUtils.isEmpty(authToken)) {
            ServiceInterceptor interceptor =
                    new ServiceInterceptor(username,authToken);

            if (!httpClient.interceptors().contains(interceptor)) {
                httpClient.addInterceptor(interceptor);

                builder.client(httpClient.build());
                retrofit = builder.build();
            }
        }

        return retrofit.create(serviceClass);
    }
     static class ServiceInterceptor implements Interceptor {

         private String mUsername,authtoken;

         public ServiceInterceptor(String username, String authToken) {
             mUsername = username;
             authtoken = authToken;
         }

         @NotNull
        @Override
        public Response intercept(@NotNull Chain chain) throws IOException {
            Request request = chain.request();
            if (request.header("No-Authentication") == null) {
                // to be replaced by real auth token once api is ready
                // auth token from shared preferences which is stored once user login
                request = request.newBuilder().addHeader("authtoken", "authtoken").addHeader("username","username").build();
            }
            return chain.proceed(request);
        }
    }
}