Java tutorial
/* * Copyright 2017 - 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.UnitsConverter; import org.traccar.model.Position; import java.net.SocketAddress; import java.nio.charset.StandardCharsets; import java.util.Date; public class TlvProtocolDecoder extends BaseProtocolDecoder { public TlvProtocolDecoder(Protocol protocol) { super(protocol); } private void sendResponse(Channel channel, SocketAddress remoteAddress, String type, String... arguments) { if (channel != null) { ByteBuf response = Unpooled.buffer(); response.writeCharSequence(type, StandardCharsets.US_ASCII); for (String argument : arguments) { response.writeByte(argument.length()); response.writeCharSequence(argument, StandardCharsets.US_ASCII); } response.writeByte(0); channel.writeAndFlush(new NetworkMessage(response, remoteAddress)); } } private String readArgument(ByteBuf buf) { return buf.readSlice(buf.readUnsignedByte()).toString(StandardCharsets.US_ASCII); } @Override protected Object decode(Channel channel, SocketAddress remoteAddress, Object msg) throws Exception { ByteBuf buf = (ByteBuf) msg; String type = buf.readSlice(2).toString(StandardCharsets.US_ASCII); if (channel != null) { switch (type) { case "0A": case "0C": sendResponse(channel, remoteAddress, type); break; case "0B": sendResponse(channel, remoteAddress, type, "1482202689", "10", "20", "15"); break; case "0E": case "0F": sendResponse(channel, remoteAddress, type, "30", "Unknown"); break; default: break; } } if (type.equals("0E")) { DeviceSession deviceSession = getDeviceSession(channel, remoteAddress, readArgument(buf)); if (deviceSession == null) { return null; } Position position = new Position(getProtocolName()); position.setDeviceId(deviceSession.getDeviceId()); position.setValid(true); position.setTime(new Date(Long.parseLong(readArgument(buf)) * 1000)); readArgument(buf); // location identifier position.setLongitude(Double.parseDouble(readArgument(buf))); position.setLatitude(Double.parseDouble(readArgument(buf))); position.setSpeed(UnitsConverter.knotsFromKph(Double.parseDouble(readArgument(buf)))); position.setCourse(Double.parseDouble(readArgument(buf))); position.set(Position.KEY_SATELLITES, Integer.parseInt(readArgument(buf))); return position; } return null; } }