Java tutorial
/******************************************************************************* * This file is part of OpenNMS(R). * * Copyright (C) 2010-2012 The OpenNMS Group, Inc. * OpenNMS(R) is Copyright (C) 1999-2012 The OpenNMS Group, Inc. * * OpenNMS(R) is a registered trademark of The OpenNMS Group, Inc. * * OpenNMS(R) 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. * * OpenNMS(R) 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 OpenNMS(R). If not, see: * http://www.gnu.org/licenses/ * * For more information contact: * OpenNMS(R) Licensing <license@opennms.org> * http://www.opennms.org/ * http://www.opennms.com/ *******************************************************************************/ package org.opennms.features.poller.remote.gwt.server.geocoding; import java.io.InputStream; import java.io.UnsupportedEncodingException; import java.net.URLEncoder; import java.util.List; import net.simon04.jelementtree.ElementTree; import org.apache.http.client.HttpClient; import org.apache.http.client.methods.HttpGet; import org.apache.http.client.methods.HttpUriRequest; import org.apache.http.impl.client.DefaultHttpClient; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.opennms.features.poller.remote.gwt.client.GWTLatLng; /** * <p>MapquestGeocoder class.</p> * * @author ranger * @version $Id: $ * @since 1.8.1 */ public class MapquestGeocoder implements Geocoder { private static final Logger LOG = LoggerFactory.getLogger(MapquestGeocoder.class); public enum Quality { COUNTRY, STATE, ZIP, COUNTY, ZIP_EXTENDED, CITY, STREET, INTERSECTION, ADDRESS, POINT } private static final String GEOCODE_URL = "http://www.mapquestapi.com/geocoding/v1/address?callback=renderGeocode&outFormat=xml"; private static final HttpClient m_httpClient = new DefaultHttpClient(); private String m_apiKey; private Quality m_minimumQuality; private String m_referer; /** * <p>Constructor for MapquestGeocoder.</p> */ public MapquestGeocoder() { m_apiKey = System.getProperty("gwt.apikey"); m_referer = System.getProperty("gwt.geocoder.referer"); final String minimumQuality = System.getProperty("gwt.geocoder.minimumQuality"); if (minimumQuality != null) { m_minimumQuality = Quality.valueOf(minimumQuality); } } /** * <p>Constructor for MapquestGeocoder.</p> * * @param apiKey a {@link java.lang.String} object. */ public MapquestGeocoder(String apiKey) { this(); m_apiKey = apiKey; } /** {@inheritDoc} */ @Override public GWTLatLng geocode(final String geolocation) throws GeocoderException { final HttpUriRequest method = new HttpGet(getUrl(geolocation)); method.addHeader("User-Agent", "OpenNMS-MapQuestGeocoder/1.0"); method.addHeader("Referer", m_referer); try { InputStream responseStream = m_httpClient.execute(method).getEntity().getContent(); final ElementTree tree = ElementTree.fromStream(responseStream); if (tree == null) { throw new GeocoderException( "an error occurred connecting to the MapQuest geocoding service (no XML tree was found)"); } final ElementTree statusCode = tree.find("//statusCode"); if (statusCode == null || !statusCode.getText().equals("0")) { final String code = (statusCode == null ? "unknown" : statusCode.getText()); final ElementTree messageTree = tree.find("//message"); final String message = (messageTree == null ? "unknown" : messageTree.getText()); throw new GeocoderException("an error occurred when querying MapQuest (statusCode=" + code + ", message=" + message + ")"); } final List<ElementTree> locations = tree.findAll("//location"); if (locations.size() > 1) { LOG.warn("more than one location returned for query: {}", geolocation); } else if (locations.size() == 0) { throw new GeocoderException("MapQuest returned an OK status code, but no locations"); } final ElementTree location = locations.get(0); // first, check the quality if (m_minimumQuality != null) { final Quality geocodeQuality = Quality .valueOf(location.find("//geocodeQuality").getText().toUpperCase()); if (geocodeQuality.compareTo(m_minimumQuality) < 0) { throw new GeocoderException("response did not meet minimum quality requirement (" + geocodeQuality + " is less specific than " + m_minimumQuality + ")"); } } // then, extract the lat/lng final ElementTree latLng = location.find("//latLng"); Double latitude = Double.valueOf(latLng.find("//lat").getText()); Double longitude = Double.valueOf(latLng.find("//lng").getText()); return new GWTLatLng(latitude, longitude); } catch (GeocoderException e) { throw e; } catch (Throwable e) { throw new GeocoderException("unable to get lat/lng from MapQuest", e); } } private String getUrl(String geolocation) throws GeocoderException { try { return GEOCODE_URL + "&key=" + m_apiKey + "&location=" + URLEncoder.encode(geolocation, "UTF-8"); } catch (UnsupportedEncodingException e) { throw new GeocoderException("unable to URL-encode query string", e); } } }