Java tutorial
/* * Copyright 2015 - 2018 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 io.netty.buffer.ByteBuf; import io.netty.buffer.Unpooled; import io.netty.channel.Channel; import org.traccar.BaseProtocolDecoder; import org.traccar.DeviceSession; import org.traccar.NetworkMessage; import org.traccar.Protocol; import org.traccar.helper.BitUtil; import org.traccar.model.CellTower; import org.traccar.model.Network; import org.traccar.model.Position; import java.net.SocketAddress; import java.nio.charset.StandardCharsets; import java.util.Date; public class ThinkRaceProtocolDecoder extends BaseProtocolDecoder { public ThinkRaceProtocolDecoder(Protocol protocol) { super(protocol); } public static final int MSG_LOGIN = 0x80; public static final int MSG_GPS = 0x90; private static double convertCoordinate(long raw, boolean negative) { long degrees = raw / 1000000; double minutes = (raw % 1000000) * 0.0001; double result = degrees + minutes / 60; if (negative) { result = -result; } return result; } @Override protected Object decode(Channel channel, SocketAddress remoteAddress, Object msg) throws Exception { ByteBuf buf = (ByteBuf) msg; buf.skipBytes(2); // header ByteBuf id = buf.readSlice(12); buf.readUnsignedByte(); // separator int type = buf.readUnsignedByte(); buf.readUnsignedShort(); // length if (type == MSG_LOGIN) { int command = buf.readUnsignedByte(); // 0x00 - heartbeat if (command == 0x01) { String imei = buf.toString(buf.readerIndex(), 15, StandardCharsets.US_ASCII); DeviceSession deviceSession = getDeviceSession(channel, remoteAddress, imei); if (deviceSession != null && channel != null) { ByteBuf response = Unpooled.buffer(); response.writeByte(0x48); response.writeByte(0x52); // header response.writeBytes(id); response.writeByte(0x2c); // separator response.writeByte(type); response.writeShort(0x0002); // length response.writeShort(0x8000); response.writeShort(0x0000); // checksum channel.writeAndFlush(new NetworkMessage(response, remoteAddress)); } } } else if (type == MSG_GPS) { DeviceSession deviceSession = getDeviceSession(channel, remoteAddress); if (deviceSession == null) { return null; } Position position = new Position(getProtocolName()); position.setDeviceId(deviceSession.getDeviceId()); position.setTime(new Date(buf.readUnsignedInt() * 1000)); int flags = buf.readUnsignedByte(); position.setValid(true); position.setLatitude(convertCoordinate(buf.readUnsignedInt(), !BitUtil.check(flags, 0))); position.setLongitude(convertCoordinate(buf.readUnsignedInt(), !BitUtil.check(flags, 1))); position.setSpeed(buf.readUnsignedByte()); position.setCourse(buf.readUnsignedByte()); position.setNetwork( new Network(CellTower.fromLacCid(buf.readUnsignedShort(), buf.readUnsignedShort()))); return position; } return null; } }