EnforaProtocolDecoder.java

/*
 * Copyright 2012 - 2015 Anton Tananaev (anton@traccar.org)
 *
 * 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 org.traccar.protocol;

import org.jboss.netty.buffer.ChannelBuffer;
import org.jboss.netty.buffer.ChannelBufferIndexFinder;
import org.jboss.netty.channel.Channel;
import org.traccar.BaseProtocolDecoder;
import org.traccar.DeviceSession;
import org.traccar.helper.DateBuilder;
import org.traccar.helper.Parser;
import org.traccar.helper.PatternBuilder;
import org.traccar.helper.StringFinder;
import org.traccar.model.Position;

import java.net.SocketAddress;
import java.nio.charset.StandardCharsets;
import java.util.regex.Pattern;

public class EnforaProtocolDecoder extends BaseProtocolDecoder {

    public EnforaProtocolDecoder(EnforaProtocol protocol) {
        super(protocol);
    }

    private static final Pattern PATTERN = new PatternBuilder()
            .text("GPRMC,")
            .number("(dd)(dd)(dd).?d*,")         // time (hhmmss)
            .expression("([AV]),")               // validity
            .number("(dd)(dd.d+),")              // latitude
            .expression("([NS]),")
            .number("(ddd)(dd.d+),")             // longitude
            .expression("([EW]),")
            .number("(d+.d+)?,")                 // speed
            .number("(d+.d+)?,")                 // course
            .number("(dd)(dd)(dd),")             // date (ddmmyy)
            .any()
            .compile();

    public static final int IMEI_LENGTH = 15;

    @Override
    protected Object decode(
            Channel channel, SocketAddress remoteAddress, Object msg) throws Exception {

        ChannelBuffer buf = (ChannelBuffer) msg;

        // Find IMEI number
        int index = buf.indexOf(buf.readerIndex(), buf.writerIndex(), new ChannelBufferIndexFinder() {
            @Override
            public boolean find(ChannelBuffer buffer, int guessedIndex) {
                if (buffer.writerIndex() - guessedIndex >= IMEI_LENGTH) {
                    for (int i = 0; i < IMEI_LENGTH; i++) {
                        if (!Character.isDigit((char) buffer.getByte(guessedIndex + i))) {
                            return false;
                        }
                    }
                    return true;
                }
                return false;
            }
        });
        if (index == -1) {
            return null;
        }

        String imei = buf.toString(index, IMEI_LENGTH, StandardCharsets.US_ASCII);
        DeviceSession deviceSession = getDeviceSession(channel, remoteAddress, imei);
        if (deviceSession == null) {
            return null;
        }

        // Find NMEA sentence
        int start = buf.indexOf(buf.readerIndex(), buf.writerIndex(), new StringFinder("GPRMC"));
        if (start == -1) {
            return null;
        }

        String sentence = buf.toString(start, buf.readableBytes() - start, StandardCharsets.US_ASCII);
        Parser parser = new Parser(PATTERN, sentence);
        if (!parser.matches()) {
            return null;
        }

        Position position = new Position();
        position.setProtocol(getProtocolName());
        position.setDeviceId(deviceSession.getDeviceId());

        DateBuilder dateBuilder = new DateBuilder()
                .setTime(parser.nextInt(0), parser.nextInt(0), parser.nextInt(0));

        position.setValid(parser.next().equals("A"));
        position.setLatitude(parser.nextCoordinate());
        position.setLongitude(parser.nextCoordinate());
        position.setSpeed(parser.nextDouble(0));
        position.setCourse(parser.nextDouble(0));

        dateBuilder.setDateReverse(parser.nextInt(0), parser.nextInt(0), parser.nextInt(0));
        position.setTime(dateBuilder.getDate());

        return position;
    }

}