Java tutorial
/* * Copyright (C) 2010 Dudie * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ package fr.dudie.keolis.client; import java.lang.reflect.Type; import java.util.List; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import com.google.gson.Gson; import com.google.gson.GsonBuilder; import com.google.gson.JsonParseException; import com.google.gson.reflect.TypeToken; import fr.dudie.keolis.gson.BikeStationDeserializer; import fr.dudie.keolis.gson.LineAlertDataDeserializer; import fr.dudie.keolis.gson.SubwayStationDeserializer; import fr.dudie.keolis.model.ApiResponse; import fr.dudie.keolis.model.BikeStation; import fr.dudie.keolis.model.LineAlertData; import fr.dudie.keolis.model.StatusAttributes; import fr.dudie.keolis.model.SubwayStation; /** * Utilities for Keolis service. * * @author Olivier Boudet */ public final class KeoUtils { /** The event logger. */ private static final Logger LOGGER = LoggerFactory.getLogger(KeoUtils.class); /** Gson instance for Keolis api calls. */ private static Gson gsonInstance; /** * Private constructor to avoid instantiation. */ private KeoUtils() { } /** * Checks the response code of the keolis API and return the JSON Object named "data". * * @param apiResponse * the response of the keolis API * @param <T> * type of data returned by the API * @throws JSONException * the response does not contains valid data */ public static <T> void checkResponse(final ApiResponse<T> apiResponse) throws JsonParseException { final StatusAttributes attributes = apiResponse.getOpendata().getAnswer().getStatus().getAttributes(); if (LOGGER.isDebugEnabled()) { LOGGER.debug("checking keolis response - code = {}, message = {}", attributes.getCode(), attributes.getMessage()); } if (attributes.getCode() != 0) { final String message = String.format("Keolis API error : code=%S, %s ", attributes.getCode(), attributes.getMessage()); throw new JsonParseException(message); } } /** * Gets a gson instance dedicated to Keolis API. * * @return the gson instance */ public static Gson getGsonInstance() { if (gsonInstance == null) { final GsonBuilder gsonBuilder = new GsonBuilder(); gsonBuilder.setDateFormat("yyyy-MM-dd'T'HH:mm:ss"); // type adapter needed just because "data" object in the response can be an array or an // empty string. final Type lineAlertDataType = new TypeToken<LineAlertData>() { }.getType(); gsonBuilder.registerTypeAdapter(lineAlertDataType, new LineAlertDataDeserializer()); final Type listOfSubwayStation = new TypeToken<List<SubwayStation>>() { }.getType(); gsonBuilder.registerTypeAdapter(listOfSubwayStation, new SubwayStationDeserializer()); final Type listOfBikeStation = new TypeToken<List<BikeStation>>() { }.getType(); gsonBuilder.registerTypeAdapter(listOfBikeStation, new BikeStationDeserializer()); gsonInstance = gsonBuilder.create(); } return gsonInstance; } }