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.helper.Checksum; import org.traccar.helper.DateBuilder; import org.traccar.helper.UnitsConverter; import org.traccar.model.Position; import java.net.SocketAddress; public class MxtProtocolDecoder extends BaseProtocolDecoder { public MxtProtocolDecoder(Protocol protocol) { super(protocol); } public static final int MSG_ACK = 0x02; public static final int MSG_NACK = 0x03; public static final int MSG_POSITION = 0x31; private static void sendResponse(Channel channel, int device, long id, int crc) { if (channel != null) { ByteBuf response = Unpooled.buffer(); response.writeByte(device); response.writeByte(MSG_ACK); response.writeIntLE((int) id); response.writeShortLE(crc); response.writeShortLE(Checksum.crc16(Checksum.CRC16_XMODEM, response.nioBuffer())); ByteBuf encoded = Unpooled.buffer(); encoded.writeByte(0x01); // header while (response.isReadable()) { int b = response.readByte(); if (b == 0x01 || b == 0x04 || b == 0x10 || b == 0x11 || b == 0x13) { encoded.writeByte(0x10); b += 0x20; } encoded.writeByte(b); } response.release(); encoded.writeByte(0x04); // ending channel.writeAndFlush(new NetworkMessage(encoded, channel.remoteAddress())); } } @Override protected Object decode(Channel channel, SocketAddress remoteAddress, Object msg) throws Exception { ByteBuf buf = (ByteBuf) msg; buf.readUnsignedByte(); // start int device = buf.readUnsignedByte(); // device descriptor int type = buf.readUnsignedByte(); long id = buf.readUnsignedIntLE(); DeviceSession deviceSession = getDeviceSession(channel, remoteAddress, String.valueOf(id)); if (deviceSession == null) { return null; } if (type == MSG_POSITION) { Position position = new Position(getProtocolName()); position.setDeviceId(deviceSession.getDeviceId()); buf.readUnsignedByte(); // protocol int infoGroups = buf.readUnsignedByte(); position.set(Position.KEY_INDEX, buf.readUnsignedShortLE()); DateBuilder dateBuilder = new DateBuilder().setDate(2000, 1, 1); long date = buf.readUnsignedIntLE(); long days = BitUtil.from(date, 6 + 6 + 5); long hours = BitUtil.between(date, 6 + 6, 6 + 6 + 5); long minutes = BitUtil.between(date, 6, 6 + 6); long seconds = BitUtil.to(date, 6); dateBuilder.addMillis((((days * 24 + hours) * 60 + minutes) * 60 + seconds) * 1000); position.setTime(dateBuilder.getDate()); position.setValid(true); position.setLatitude(buf.readIntLE() / 1000000.0); position.setLongitude(buf.readIntLE() / 1000000.0); long flags = buf.readUnsignedIntLE(); position.set(Position.KEY_IGNITION, BitUtil.check(flags, 0)); if (BitUtil.check(flags, 1)) { position.set(Position.KEY_ALARM, Position.ALARM_GENERAL); } position.set(Position.KEY_INPUT, BitUtil.between(flags, 2, 7)); position.set(Position.KEY_OUTPUT, BitUtil.between(flags, 7, 10)); position.setCourse(BitUtil.between(flags, 10, 13) * 45); // position.setValid(BitUtil.check(flags, 15)); position.set(Position.KEY_CHARGE, BitUtil.check(flags, 20)); position.setSpeed(UnitsConverter.knotsFromKph(buf.readUnsignedByte())); buf.readUnsignedByte(); // input mask if (BitUtil.check(infoGroups, 0)) { buf.skipBytes(8); // waypoints } if (BitUtil.check(infoGroups, 1)) { buf.skipBytes(8); // wireless accessory } if (BitUtil.check(infoGroups, 2)) { position.set(Position.KEY_SATELLITES, buf.readUnsignedByte()); position.set(Position.KEY_HDOP, buf.readUnsignedByte()); position.setAccuracy(buf.readUnsignedByte()); position.set(Position.KEY_RSSI, buf.readUnsignedByte()); buf.readUnsignedShortLE(); // time since boot position.set(Position.KEY_POWER, buf.readUnsignedByte()); position.set(Position.PREFIX_TEMP + 1, buf.readByte()); } if (BitUtil.check(infoGroups, 3)) { position.set(Position.KEY_ODOMETER, buf.readUnsignedIntLE()); } if (BitUtil.check(infoGroups, 4)) { position.set(Position.KEY_HOURS, UnitsConverter.msFromMinutes(buf.readUnsignedIntLE())); } if (BitUtil.check(infoGroups, 5)) { buf.readUnsignedIntLE(); // reason } if (BitUtil.check(infoGroups, 6)) { position.set(Position.KEY_POWER, buf.readUnsignedShortLE() * 0.001); position.set(Position.KEY_BATTERY, buf.readUnsignedShortLE()); } if (BitUtil.check(infoGroups, 7)) { position.set(Position.KEY_DRIVER_UNIQUE_ID, String.valueOf(buf.readUnsignedIntLE())); } buf.readerIndex(buf.writerIndex() - 3); sendResponse(channel, device, id, buf.readUnsignedShortLE()); return position; } return null; } }