Java tutorial
/** * Global Sensor Networks (GSN) Source Code * Copyright (c) 2006-2014, Ecole Polytechnique Federale de Lausanne (EPFL) * * This file is part of GSN. * * GSN 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. * * GSN 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 GSN. If not, see <http://www.gnu.org/licenses/>. * * File: src/gsn/wrappers/HttpGetAndroidWrapper.java * * @author Sofiane Sarni * */ /******************************************************************************* * Copyright 2012 Colin Cachia * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. ******************************************************************************/ package gsn.wrappers; import gsn.beans.AddressBean; import gsn.beans.DataField; import gsn.beans.DataTypes; import gsn.beans.StreamElement; import gsn.wrappers.AbstractWrapper; import gsn.utils.ParamParser; import org.w3c.dom.CharacterData; import org.w3c.dom.Document; import org.w3c.dom.Element; import org.w3c.dom.Node; import org.w3c.dom.NodeList; import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.DocumentBuilderFactory; import java.io.BufferedInputStream; import java.io.IOException; import java.io.Serializable; import java.net.HttpURLConnection; import java.net.MalformedURLException; import java.net.URL; import java.net.URLConnection; import org.apache.commons.io.output.ByteArrayOutputStream; import org.slf4j.LoggerFactory; import org.slf4j.Logger; public class HttpGetAndroidWrapper extends AbstractWrapper { private int DEFAULT_RATE = 2000; private static int threadCounter = 0; private final transient Logger logger = LoggerFactory.getLogger(HttpGetAndroidWrapper.class); private static String urlPath, Longitude, Latitude; private HttpURLConnection httpURLConnection; private URL url; private AddressBean addressBean; private String inputRate; private static final String FIELD_NAME_LONG = "Longitude"; private static final String FIELD_NAME_LAT = "Latitude"; private static final String[] FIELD_NAMES = new String[] { FIELD_NAME_LONG, FIELD_NAME_LAT }; private int rate; //private transient final DataField [] outputStructure = new DataField [] { new DataField( "longitude" , "Double" , "Longitude Data from Network-Connected Android Smartphone." ), new DataField( "latitude" , "Double" , "Latitude Data from Network-Connected Android Smartphone." ) }; /** * From XML file it needs the followings : * <ul> * <li>url</li> The full url for retriving the binary data. * <li>rate</li> The interval in msec for updating/asking for new information. * <li>mime</li> Type of the binary data. * </ul> */ public boolean initialize() { this.addressBean = getActiveAddressBean(); urlPath = this.addressBean.getPredicateValue("url"); try { url = new URL(urlPath); } catch (MalformedURLException e) { logger.error("Loading the http android wrapper failed : " + e.getMessage(), e); return false; } inputRate = this.addressBean.getPredicateValue("rate"); if (inputRate == null || inputRate.trim().length() == 0) rate = DEFAULT_RATE; else rate = Integer.parseInt(inputRate); logger.debug("AndroidWrapper is now running @" + rate + " Rate."); return true; } public void run() { while (isActive()) { parseXML(); } } public String getWrapperName() { return "Http Android Receiver"; } public void dispose() { threadCounter--; } public DataField[] getOutputFormat() { DataField[] outputFormat = new DataField[2]; outputFormat[0] = new DataField("Longitude", "Double", "Longitude value from Android Smartphone"); outputFormat[1] = new DataField("Latitude", "Double", "Latitude value from Android Smartphone"); return outputFormat; } private void parseXML() { URL url; try { url = new URL(urlPath); URLConnection conn = url.openConnection(); DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); DocumentBuilder builder = factory.newDocumentBuilder(); Document doc = builder.parse(conn.getInputStream()); NodeList nodes = doc.getElementsByTagName("stream-element"); for (int i = 0; i < nodes.getLength(); i++) { Element element = (Element) nodes.item(i); NodeList Long = element.getElementsByTagName("long"); Element line = (Element) Long.item(0); Longitude = getCharacterDataFromElement(line); NodeList Lat = element.getElementsByTagName("lat"); line = (Element) Lat.item(0); Latitude = getCharacterDataFromElement(line); } StreamElement streamElement = new StreamElement(FIELD_NAMES, new Byte[] { DataTypes.DOUBLE, DataTypes.DOUBLE }, new Serializable[] { Double.parseDouble(Longitude), Double.parseDouble(Latitude) }, System.currentTimeMillis()); postStreamElement(streamElement); } catch (Exception e) { logger.error(e.getMessage(), e); } } public static String getCharacterDataFromElement(Element e) { Node child = e.getFirstChild(); if (child instanceof CharacterData) { CharacterData cd = (CharacterData) child; return cd.getData(); } return "?"; } }