Java tutorial
/* * Copyright 2019 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.channel.Channel; import org.traccar.BaseProtocolDecoder; import org.traccar.DeviceSession; import org.traccar.Protocol; import org.traccar.helper.BitUtil; import org.traccar.helper.DateBuilder; import org.traccar.helper.ObdDecoder; import org.traccar.helper.UnitsConverter; import org.traccar.model.Position; import java.net.SocketAddress; import java.nio.charset.StandardCharsets; public class NyitechProtocolDecoder extends BaseProtocolDecoder { public NyitechProtocolDecoder(Protocol protocol) { super(protocol); } public static final short MSG_LOGIN = 0x1001; public static final short MSG_COMPREHENSIVE_LIVE = 0x2001; public static final short MSG_COMPREHENSIVE_HISTORY = 0x2002; public static final short MSG_ALARM = 0x2003; public static final short MSG_FIXED = 0x2004; private void decodeLocation(Position position, ByteBuf buf) { DateBuilder dateBuilder = new DateBuilder() .setDateReverse(buf.readUnsignedByte(), buf.readUnsignedByte(), buf.readUnsignedByte()) .setTime(buf.readUnsignedByte(), buf.readUnsignedByte(), buf.readUnsignedByte()); position.setTime(dateBuilder.getDate()); int flags = buf.readUnsignedByte(); position.setValid(BitUtil.to(flags, 2) > 0); double lat = buf.readUnsignedIntLE() / 3600000.0; double lon = buf.readUnsignedIntLE() / 3600000.0; position.setLatitude(BitUtil.check(flags, 2) ? lat : -lat); position.setLongitude(BitUtil.check(flags, 3) ? lon : -lon); position.setSpeed(UnitsConverter.knotsFromCps(buf.readUnsignedShortLE())); position.setCourse(buf.readUnsignedShortLE() * 0.1); position.setAltitude(buf.readShortLE() * 0.1); } private String decodeAlarm(int type) { switch (type) { case 0x09: return Position.ALARM_ACCELERATION; case 0x0a: return Position.ALARM_BRAKING; case 0x0b: return Position.ALARM_CORNERING; case 0x0e: return Position.ALARM_SOS; default: return null; } } @Override protected Object decode(Channel channel, SocketAddress remoteAddress, Object msg) throws Exception { ByteBuf buf = (ByteBuf) msg; buf.skipBytes(2); // header buf.readUnsignedShortLE(); // length String id = buf.readCharSequence(12, StandardCharsets.US_ASCII).toString(); DeviceSession deviceSession = getDeviceSession(channel, remoteAddress, id); if (deviceSession == null) { return null; } int type = buf.readUnsignedShortLE(); if (type != MSG_LOGIN && type != MSG_COMPREHENSIVE_LIVE && type != MSG_COMPREHENSIVE_HISTORY && type != MSG_ALARM && type != MSG_FIXED) { return null; } Position position = new Position(getProtocolName()); position.setDeviceId(deviceSession.getDeviceId()); if (type == MSG_COMPREHENSIVE_LIVE || type == MSG_COMPREHENSIVE_HISTORY) { buf.skipBytes(6); // time boolean includeLocation = buf.readUnsignedByte() > 0; boolean includeObd = buf.readUnsignedByte() > 0; buf.readUnsignedByte(); // include sensor if (includeLocation) { decodeLocation(position, buf); } else { getLastLocation(position, null); } if (includeObd) { int count = buf.readUnsignedByte(); for (int i = 0; i < count; i++) { int pid = buf.readUnsignedShortLE(); int length = buf.readUnsignedByte(); switch (length) { case 1: position.add(ObdDecoder.decodeData(pid, buf.readByte(), true)); break; case 2: position.add(ObdDecoder.decodeData(pid, buf.readShortLE(), true)); break; case 4: position.add(ObdDecoder.decodeData(pid, buf.readIntLE(), true)); break; default: buf.skipBytes(length); break; } } } position.set(Position.KEY_FUEL_USED, buf.readUnsignedInt() * 0.01); position.set(Position.KEY_ODOMETER_TRIP, buf.readUnsignedInt()); } else if (type == MSG_ALARM) { buf.readUnsignedShortLE(); // random number buf.readUnsignedByte(); // tag position.set(Position.KEY_ALARM, decodeAlarm(buf.readUnsignedByte())); buf.readUnsignedShortLE(); // threshold buf.readUnsignedShortLE(); // value buf.skipBytes(6); // time decodeLocation(position, buf); } else if (type == MSG_FIXED) { buf.skipBytes(6); // time decodeLocation(position, buf); } else { decodeLocation(position, buf); } return position; } }