Java tutorial
/* * The MIT License * * Copyright 2015 Ivar Grimstad (ivar.grimstad@gmail.com). * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. */ package eu.agilejava.snoop.scan; import com.fasterxml.jackson.dataformat.yaml.snakeyaml.Yaml; import com.fasterxml.jackson.dataformat.yaml.snakeyaml.error.YAMLException; import eu.agilejava.snoop.SnoopConfigurationException; import eu.agilejava.snoop.client.SnoopConfig; import java.io.IOException; import java.net.URI; import java.util.Calendar; import java.util.Collections; import java.util.Map; import java.util.Optional; import java.util.logging.Logger; import javax.annotation.PostConstruct; import javax.annotation.PreDestroy; import javax.annotation.Resource; import javax.ejb.ScheduleExpression; import javax.ejb.Singleton; import javax.ejb.Startup; import javax.ejb.TimedObject; import javax.ejb.Timeout; import javax.ejb.Timer; import javax.ejb.TimerConfig; import javax.ejb.TimerService; import javax.websocket.ClientEndpoint; import javax.websocket.ContainerProvider; import javax.websocket.DeploymentException; import javax.websocket.OnMessage; import javax.websocket.Session; import javax.websocket.WebSocketContainer; /** * Registers with Snoop and gives heartbeats every 10 second. * * @author Ivar Grimstad (ivar.grimstad@gmail.com) */ @ClientEndpoint @Singleton @Startup public class SnoopRegistrationClient { private static final Logger LOGGER = Logger.getLogger("eu.agilejava.snoop"); private static final String REGISTER_ENDPOINT = "snoop"; private static final String STATUS_ENDPOINT = "snoopstatus/"; private String serviceUrl; private final SnoopConfig applicationConfig = new SnoopConfig(); @Resource private TimerService timerService; @PostConstruct private void init() { LOGGER.config("Checking if snoop is enabled"); if (SnoopExtensionHelper.isSnoopEnabled()) { try { readConfiguration(); LOGGER.config(() -> "Registering " + applicationConfig.getServiceName()); register(applicationConfig.getServiceName()); } catch (SnoopConfigurationException e) { LOGGER.severe(() -> "Snoop is enabled but not configured properly: " + e.getMessage()); } } else { LOGGER.config("Snoop is not enabled. Use @EnableSnoopClient!"); } } public void register(final String clientId) { sendMessage(REGISTER_ENDPOINT, applicationConfig.toJSON()); ScheduleExpression schedule = new ScheduleExpression(); schedule.second("*/10").minute("*").hour("*").start(Calendar.getInstance().getTime()); TimerConfig config = new TimerConfig(); config.setPersistent(false); Timer timer = timerService.createCalendarTimer(schedule, config); LOGGER.config(() -> timer.getSchedule().toString()); } /** * Handles incoming message. * * @param session The WebSocket session * @param message The message */ @OnMessage public void onMessage(Session session, String message) { LOGGER.config(() -> "Message: " + message); sendMessage(STATUS_ENDPOINT + applicationConfig.getServiceName(), applicationConfig.toJSON()); } @Timeout public void health(Timer timer) { LOGGER.config(() -> "health update: " + Calendar.getInstance().getTime()); LOGGER.config(() -> "Next: " + timer.getNextTimeout()); sendMessage(STATUS_ENDPOINT + applicationConfig.getServiceName(), applicationConfig.toJSON()); } /** * Sends message to the WebSocket server. * * @param endpoint The server endpoint * @param msg The message * @return a return message */ private String sendMessage(String endpoint, String msg) { LOGGER.config(() -> "Sending message: " + msg); String returnValue = "-1"; try { WebSocketContainer container = ContainerProvider.getWebSocketContainer(); String uri = serviceUrl + endpoint; Session session = container.connectToServer(this, URI.create(uri)); session.getBasicRemote().sendText(msg != null ? msg : ""); returnValue = session.getId(); } catch (DeploymentException | IOException ex) { LOGGER.warning(ex.getMessage()); } return returnValue; } @PreDestroy private void deregister() { LOGGER.config(() -> "Deregistering " + applicationConfig.getServiceName()); sendMessage(STATUS_ENDPOINT + applicationConfig.getServiceName(), null); } private void readConfiguration() throws SnoopConfigurationException { Map<String, Object> snoopConfig = Collections.EMPTY_MAP; try { Yaml yaml = new Yaml(); Map<String, Object> props = (Map<String, Object>) yaml .load(Thread.currentThread().getContextClassLoader().getResourceAsStream("/snoop.yml")); snoopConfig = (Map<String, Object>) props.get("snoop"); } catch (YAMLException e) { LOGGER.config(() -> "No configuration file. Using env properties."); } applicationConfig.setServiceName(SnoopExtensionHelper.getServiceName()); final String host = readProperty("host", snoopConfig); final String port = readProperty("port", snoopConfig); applicationConfig.setServiceHome(host + ":" + port + "/"); applicationConfig.setServiceRoot(readProperty("serviceRoot", snoopConfig)); LOGGER.config(() -> "application config: " + applicationConfig.toJSON()); serviceUrl = "ws://" + readProperty("snoopService", snoopConfig); } private String readProperty(final String key, Map<String, Object> snoopConfig) { String property = Optional.ofNullable(System.getProperty(key)).orElseGet(() -> { String envProp = Optional.ofNullable(System.getenv(applicationConfig.getServiceName() + "." + key)) .orElseGet(() -> { String confProp = Optional.ofNullable(snoopConfig.get(key)).orElseThrow(() -> { return new SnoopConfigurationException( key + " must be configured either in application.yml or as env parameter"); }).toString(); return confProp; }); return envProp; }); return property; } }