Java tutorial
/** * Copyright (c) 2014-2017 by the respective copyright holders. * All rights reserved. This program and the accompanying materials * are made available under the terms of the Eclipse Public License v1.0 * which accompanies this distribution, and is available at * http://www.eclipse.org/legal/epl-v10.html */ package org.eclipse.smarthome.binding.yahooweather.handler; import static org.eclipse.smarthome.binding.yahooweather.YahooWeatherBindingConstants.*; import java.io.IOException; import java.math.BigDecimal; import java.net.MalformedURLException; import java.net.URL; import java.net.URLConnection; import java.util.ArrayList; import java.util.Collection; import java.util.concurrent.ScheduledFuture; import java.util.concurrent.TimeUnit; import org.apache.commons.io.IOUtils; import org.apache.commons.lang.StringUtils; import org.eclipse.smarthome.binding.yahooweather.internal.ExpiringCache; import org.eclipse.smarthome.config.core.Configuration; import org.eclipse.smarthome.config.core.status.ConfigStatusMessage; import org.eclipse.smarthome.core.library.types.DecimalType; import org.eclipse.smarthome.core.thing.ChannelUID; import org.eclipse.smarthome.core.thing.Thing; import org.eclipse.smarthome.core.thing.ThingStatus; import org.eclipse.smarthome.core.thing.ThingStatusDetail; import org.eclipse.smarthome.core.thing.binding.ConfigStatusThingHandler; import org.eclipse.smarthome.core.types.Command; import org.eclipse.smarthome.core.types.RefreshType; import org.eclipse.smarthome.core.types.State; import org.eclipse.smarthome.core.types.UnDefType; import org.slf4j.Logger; import org.slf4j.LoggerFactory; /** * The {@link YahooWeatherHandler} is responsible for handling commands, which are * sent to one of the channels. * * @author Kai Kreuzer - Initial contribution * @author Stefan Buweiler - Integrate new thing status handling * @author Thomas Hfer - Added config status provider */ public class YahooWeatherHandler extends ConfigStatusThingHandler { private static final String LOCATION_PARAM = "location"; private final Logger logger = LoggerFactory.getLogger(YahooWeatherHandler.class); private final int MAX_DATA_AGE = 3 * 60 * 60 * 1000; // 3h private final int CACHE_EXPIRY = 10 * 1000; // 10s private long lastUpdateTime; private BigDecimal location; private BigDecimal refresh; private String weatherData = null; ScheduledFuture<?> refreshJob; public YahooWeatherHandler(Thing thing) { super(thing); } @Override public void initialize() { logger.debug("Initializing YahooWeather handler."); super.initialize(); Configuration config = getThing().getConfiguration(); location = (BigDecimal) config.get(LOCATION_PARAM); try { refresh = (BigDecimal) config.get("refresh"); } catch (Exception e) { logger.debug("Cannot set refresh parameter.", e); } if (refresh == null) { // let's go for the default refresh = new BigDecimal(60); } startAutomaticRefresh(); } @Override public void dispose() { refreshJob.cancel(true); } private void startAutomaticRefresh() { Runnable runnable = new Runnable() { @Override public void run() { try { boolean success = updateWeatherData(); if (success) { updateState(new ChannelUID(getThing().getUID(), CHANNEL_TEMPERATURE), getTemperature()); updateState(new ChannelUID(getThing().getUID(), CHANNEL_HUMIDITY), getHumidity()); updateState(new ChannelUID(getThing().getUID(), CHANNEL_PRESSURE), getPressure()); } } catch (Exception e) { logger.debug("Exception occurred during execution: {}", e.getMessage(), e); } } }; refreshJob = scheduler.scheduleAtFixedRate(runnable, 0, refresh.intValue(), TimeUnit.SECONDS); } @Override public void handleCommand(ChannelUID channelUID, Command command) { if (command instanceof RefreshType) { boolean success = updateWeatherData(); if (success) { switch (channelUID.getId()) { case CHANNEL_TEMPERATURE: updateState(channelUID, getTemperature()); break; case CHANNEL_HUMIDITY: updateState(channelUID, getHumidity()); break; case CHANNEL_PRESSURE: updateState(channelUID, getPressure()); break; default: logger.debug("Command received for an unknown channel: {}", channelUID.getId()); break; } } } else { logger.debug("Command {} is not supported for channel: {}", command, channelUID.getId()); } } @Override public Collection<ConfigStatusMessage> getConfigStatus() { Collection<ConfigStatusMessage> configStatus = new ArrayList<>(); try { String locationData = getWeatherData( "SELECT location FROM weather.forecast WHERE woeid = " + location.toPlainString()); String city = getValue(locationData, "location", "city"); if (city == null) { configStatus.add( ConfigStatusMessage.Builder.error(LOCATION_PARAM).withMessageKeySuffix("location-not-found") .withArguments(location.toPlainString()).build()); } } catch (IOException e) { logger.debug("Communication error occurred while getting Yahoo weather information.", e); } return configStatus; } private synchronized boolean updateWeatherData() { try { String data = getWeatherData( "SELECT * FROM weather.forecast WHERE u = 'c' AND woeid = " + location.toPlainString()); if (data != null) { if (data.contains("\"results\":null")) { if (isCurrentDataExpired()) { weatherData = null; logger.trace( "The Yahoo Weather API did not return any data. Omiting the old result because it became too old."); updateStatus(ThingStatus.OFFLINE, ThingStatusDetail.OFFLINE.COMMUNICATION_ERROR, "The Yahoo Weather API did not return any data."); return false; } else { // simply keep the old data logger.trace("The Yahoo Weather API did not return any data. Keeping the old result."); return false; } } else { lastUpdateTime = System.currentTimeMillis(); weatherData = data; } updateStatus(ThingStatus.ONLINE); return true; } } catch (IOException e) { logger.warn("Error accessing Yahoo weather: {}", e.getMessage()); updateStatus(ThingStatus.OFFLINE, ThingStatusDetail.OFFLINE.COMMUNICATION_ERROR, e.getMessage()); } weatherData = null; return false; } private boolean isCurrentDataExpired() { return lastUpdateTime + MAX_DATA_AGE < System.currentTimeMillis(); } private final ExpiringCache<String, String> CACHE = new ExpiringCache<String, String>(CACHE_EXPIRY, new ExpiringCache.LoadAction<String, String>() { @Override public String load(String query) throws IOException { try { URL url = new URL("https://query.yahooapis.com/v1/public/yql?format=json&q=" + query.replaceAll(" ", "%20").replaceAll("'", "%27")); URLConnection connection = url.openConnection(); return IOUtils.toString(connection.getInputStream()); } catch (MalformedURLException e) { logger.debug("Constructed query url '{}' is not valid: {}", query, e.getMessage()); throw e; } } }); private String getWeatherData(String query) throws IOException { return CACHE.get(query); } private State getHumidity() { if (weatherData != null) { String humidity = getValue(weatherData, "atmosphere", "humidity"); if (humidity != null) { return new DecimalType(humidity); } } return UnDefType.UNDEF; } private State getPressure() { if (weatherData != null) { String pressure = getValue(weatherData, "atmosphere", "pressure"); if (pressure != null) { DecimalType ret = new DecimalType(pressure); if (ret.doubleValue() > 10000.0) { // Unreasonably high, record so far was 1085,8 hPa // The Yahoo API currently returns inHg values although it claims they are mbar - therefore convert ret = new DecimalType(BigDecimal.valueOf((long) (ret.doubleValue() / 0.3386388158), 2)); } return ret; } } return UnDefType.UNDEF; } private State getTemperature() { if (weatherData != null) { String temp = getValue(weatherData, "condition", "temp"); if (temp != null) { return new DecimalType(temp); } } return UnDefType.UNDEF; } private String getValue(String data, String element, String param) { String tmp = StringUtils.substringAfter(data, element); if (tmp != null) { return StringUtils.substringBetween(tmp, param + "\":\"", "\""); } return null; } }