Java tutorial
/* * Copyright 2013 - 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.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.DateBuilder; import org.traccar.helper.UnitsConverter; import org.traccar.model.Position; import java.net.SocketAddress; public class CellocatorProtocolDecoder extends BaseProtocolDecoder { public CellocatorProtocolDecoder(Protocol protocol) { super(protocol); } static final int MSG_CLIENT_STATUS = 0; static final int MSG_CLIENT_PROGRAMMING = 3; static final int MSG_CLIENT_SERIAL_LOG = 7; static final int MSG_CLIENT_SERIAL = 8; static final int MSG_CLIENT_MODULAR = 9; public static final int MSG_SERVER_ACKNOWLEDGE = 4; private byte commandCount; private void sendReply(Channel channel, SocketAddress remoteAddress, long deviceId, byte packetNumber) { if (channel != null) { ByteBuf reply = Unpooled.buffer(28); reply.writeByte('M'); reply.writeByte('C'); reply.writeByte('G'); reply.writeByte('P'); reply.writeByte(MSG_SERVER_ACKNOWLEDGE); reply.writeIntLE((int) deviceId); reply.writeByte(commandCount++); reply.writeIntLE(0); // authentication code reply.writeByte(0); reply.writeByte(packetNumber); reply.writeZero(11); byte checksum = 0; for (int i = 4; i < 27; i++) { checksum += reply.getByte(i); } reply.writeByte(checksum); channel.writeAndFlush(new NetworkMessage(reply, remoteAddress)); } } private String decodeAlarm(short reason) { switch (reason) { case 70: return Position.ALARM_SOS; case 80: return Position.ALARM_POWER_CUT; case 81: return Position.ALARM_LOW_POWER; default: return null; } } @Override protected Object decode(Channel channel, SocketAddress remoteAddress, Object msg) throws Exception { ByteBuf buf = (ByteBuf) msg; boolean alternative = buf.getByte(buf.readerIndex() + 3) != 'P'; buf.skipBytes(4); // system code int type = buf.readUnsignedByte(); long deviceUniqueId = buf.readUnsignedIntLE(); if (type != MSG_CLIENT_SERIAL) { buf.readUnsignedShortLE(); // communication control } byte packetNumber = buf.readByte(); sendReply(channel, remoteAddress, deviceUniqueId, packetNumber); if (type == MSG_CLIENT_STATUS) { Position position = new Position(getProtocolName()); DeviceSession deviceSession = getDeviceSession(channel, remoteAddress, String.valueOf(deviceUniqueId)); if (deviceSession == null) { return null; } position.setDeviceId(deviceSession.getDeviceId()); position.set(Position.KEY_VERSION_HW, buf.readUnsignedByte()); position.set(Position.KEY_VERSION_FW, buf.readUnsignedByte()); buf.readUnsignedByte(); // protocol version position.set(Position.KEY_STATUS, buf.readUnsignedByte() & 0x0f); buf.readUnsignedByte(); // operator / configuration flags buf.readUnsignedByte(); // reason data position.set(Position.KEY_ALARM, decodeAlarm(buf.readUnsignedByte())); position.set("mode", buf.readUnsignedByte()); position.set(Position.KEY_INPUT, buf.readUnsignedIntLE()); if (alternative) { buf.readUnsignedByte(); // input position.set(Position.PREFIX_ADC + 1, buf.readUnsignedShortLE()); position.set(Position.PREFIX_ADC + 2, buf.readUnsignedShortLE()); } else { buf.readUnsignedByte(); // operator position.set(Position.PREFIX_ADC + 1, buf.readUnsignedIntLE()); } position.set(Position.KEY_ODOMETER, buf.readUnsignedMediumLE()); buf.skipBytes(6); // multi-purpose data buf.readUnsignedShortLE(); // fix time buf.readUnsignedByte(); // location status buf.readUnsignedByte(); // mode 1 buf.readUnsignedByte(); // mode 2 position.set(Position.KEY_SATELLITES, buf.readUnsignedByte()); position.setValid(true); if (alternative) { position.setLongitude(buf.readIntLE() / 10000000.0); position.setLatitude(buf.readIntLE() / 10000000.0); } else { position.setLongitude(buf.readIntLE() / Math.PI * 180 / 100000000); position.setLatitude(buf.readIntLE() / Math.PI * 180 / 100000000); } position.setAltitude(buf.readIntLE() * 0.01); if (alternative) { position.setSpeed(UnitsConverter.knotsFromKph(buf.readUnsignedIntLE())); position.setCourse(buf.readUnsignedShortLE() / 1000.0); } else { position.setSpeed(UnitsConverter.knotsFromMps(buf.readUnsignedIntLE() * 0.01)); position.setCourse(buf.readUnsignedShortLE() / Math.PI * 180.0 / 1000.0); } DateBuilder dateBuilder = new DateBuilder() .setTimeReverse(buf.readUnsignedByte(), buf.readUnsignedByte(), buf.readUnsignedByte()) .setDateReverse(buf.readUnsignedByte(), buf.readUnsignedByte(), buf.readUnsignedShortLE()); position.setTime(dateBuilder.getDate()); return position; } return null; } }