frk.gpssimulator.service.impl.DefaultGpsdService.java Source code

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Here is the source code for frk.gpssimulator.service.impl.DefaultGpsdService.java

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/*
 * Copyright 2015 the original author or authors.
 *
 * 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 frk.gpssimulator.service.impl;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Calendar;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.InitializingBean;

import frk.gpssimulator.model.PositionInfo;
import frk.gpssimulator.service.GpsdService;

/**
 *
 * @author faram
 * @author Gunnar Hillert
 *
 */
public class DefaultGpsdService implements GpsdService, InitializingBean {

    private static final Logger LOGGER = LoggerFactory.getLogger(DefaultGpsdService.class);

    private BufferedWriter pipeWriter;

    public static final String GPSD_PIPE = "/tmp/gps";

    /*
     * (non-Javadoc)
     *
     * @see
     * frk.gpssimulator.service.GpsdService#updatePosition(frk.gpssimulator.
     * model.PositionInfo)
     */
    @Override
    public void updatePosition(PositionInfo position) {

        // an NMEA RMC position sentence (report) is of form:
        // $GPRMC,124426,A,5920.7019,N,02803.2893,E,,,121212,,

        Calendar cal = Calendar.getInstance();
        Integer hour = cal.get(Calendar.HOUR_OF_DAY);
        Integer minute = cal.get(Calendar.MINUTE);
        Integer second = cal.get(Calendar.SECOND);
        Integer date = cal.get(Calendar.DATE);
        Integer month = cal.get(Calendar.MONTH) + 1; // java Calendar month
        // starts at 0
        Integer year = cal.get(Calendar.YEAR) % 100; // convert to 2 digit year

        String sHour = String.format("%02d", hour);
        String sMinute = String.format("%02d", minute);
        String sSecond = String.format("%02d", second);
        String sDate = String.format("%02d", date);
        String sMonth = String.format("%02d", month);
        String sYear = String.format("%02d", year);

        String sentence = null;
        if (position == null) {
            sentence = "$GPRMC," + sHour + sMinute + sSecond + ",A,,,,,,," + sDate + sMonth + sYear + ",,";
        } else {
            double lat = position.getPosition().getLatitude();
            double lon = position.getPosition().getLongitude();

            String latSuffix = "N";
            if (lat < 0) {
                latSuffix = "S";
            }
            lat = Math.abs(lat);
            String lonSuffix = "E";
            if (lon < 0) {
                lonSuffix = "W";
            }
            lon = Math.abs(lon);

            long latDeg = (long) lat; // degree part
            double latMin = (lat - latDeg) * 60; // minute part
            long latMinWhole = (long) latMin; // whole part of minute
            Double latMinFrac = latMin - latMinWhole; // fractional part of
            // minute
            String sLatDeg = String.format("%02d", latDeg);
            String sLatMinWhole = String.format("%02d", latMinWhole);
            String sLatMinFrac = latMinFrac.toString().replace("0.", ".");
            long lonDeg = (long) lon; // degree part
            double lonMin = (lon - lonDeg) * 60; // minute part
            long lonMinWhole = (long) lonMin; // whole part of minute
            Double lonMinFrac = lonMin - lonMinWhole; // fractional part of
            // minute
            String sLonDeg = String.format("%02d", lonDeg);
            String sLonMinWhole = String.format("%02d", lonMinWhole);
            String sLonMinFrac = lonMinFrac.toString().replace("0.", ".");

            sentence = "$GPRMC," + sHour + sMinute + sSecond + ",A," + sLatDeg + sLatMinWhole + sLatMinFrac + ","
                    + latSuffix + "," + sLonDeg + sLonMinWhole + sLonMinFrac + "," + lonSuffix + ",,," + sDate
                    + sMonth + sYear + ",,";
        }

        try {
            pipeWriter.write(sentence + "\r\n");
            pipeWriter.flush();
        } catch (IOException e) {
            throw new IllegalStateException(e);
        }
    }

    /**
     * Initialize gpsd.
     * @return error message, if any
     */
    void initGpsd() throws IOException, InterruptedException {
        startProc("killall -9 gpsd", false);
        startProc("rm -f " + GPSD_PIPE, false);
        startProc("mkfifo " + GPSD_PIPE, false);
        startProc("gpsd " + GPSD_PIPE, false);
        //writer for gpsd pipe
        pipeWriter = new BufferedWriter(new FileWriter(GPSD_PIPE));

    }

    /**
     * Start given process.
     * @param command
     * @param wait for process to exit
     * @return
     */
    int startProc(String command, Boolean wait) throws IOException, InterruptedException {
        String[] commandArray = command.split(" ");
        ProcessBuilder pb = new ProcessBuilder(commandArray);
        pb.redirectErrorStream(true); //redirect errorstream and outputstream to single stream
        Process proc = pb.start();
        BufferedReader in = new BufferedReader(new InputStreamReader(proc.getInputStream()));
        String line;
        //empty the output buff of the proc
        while ((line = in.readLine()) != null) {
            LOGGER.info(line);
        }

        if (wait) {
            return proc.waitFor();
        } else {
            return 0;
        }

    }

    @Override
    public void afterPropertiesSet() throws Exception {
        if (System.getProperty("os.name").contains("Linux")) {
            try {
                initGpsd();
            } catch (IOException | InterruptedException e) {
                throw new IllegalStateException(e);
            }
        }
    }
}