Java tutorial
/* * Copyright 2013 - 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.BcdUtil; import org.traccar.helper.DateBuilder; import org.traccar.helper.UnitsConverter; import org.traccar.model.Position; import java.net.SocketAddress; public class GatorProtocolDecoder extends BaseProtocolDecoder { public GatorProtocolDecoder(Protocol protocol) { super(protocol); } public static final int MSG_HEARTBEAT = 0x21; public static final int MSG_POSITION_DATA = 0x80; public static final int MSG_ROLLCALL_RESPONSE = 0x81; public static final int MSG_ALARM_DATA = 0x82; public static final int MSG_TERMINAL_STATUS = 0x83; public static final int MSG_MESSAGE = 0x84; public static final int MSG_TERMINAL_ANSWER = 0x85; public static final int MSG_BLIND_AREA = 0x8E; public static final int MSG_PICTURE_FRAME = 0x54; public static final int MSG_CAMERA_RESPONSE = 0x56; public static final int MSG_PICTURE_DATA = 0x57; public static String decodeId(int b1, int b2, int b3, int b4) { int d1 = 30 + ((b1 >> 7) << 3) + ((b2 >> 7) << 2) + ((b3 >> 7) << 1) + (b4 >> 7); int d2 = b1 & 0x7f; int d3 = b2 & 0x7f; int d4 = b3 & 0x7f; int d5 = b4 & 0x7f; return String.format("%02d%02d%02d%02d%02d", d1, d2, d3, d4, d5); } private void sendResponse(Channel channel, SocketAddress remoteAddress, byte calibration) { if (channel != null) { ByteBuf response = Unpooled.buffer(); response.writeByte(0x24); response.writeByte(0x24); // header response.writeByte(MSG_HEARTBEAT); // size response.writeShort(5); response.writeByte(calibration); response.writeByte(0); // main order response.writeByte(0); // slave order response.writeByte(1); // calibration response.writeByte(0x0D); channel.writeAndFlush(new NetworkMessage(response, remoteAddress)); } } @Override protected Object decode(Channel channel, SocketAddress remoteAddress, Object msg) throws Exception { ByteBuf buf = (ByteBuf) msg; buf.skipBytes(2); // header int type = buf.readUnsignedByte(); buf.readUnsignedShort(); // length String id = decodeId(buf.readUnsignedByte(), buf.readUnsignedByte(), buf.readUnsignedByte(), buf.readUnsignedByte()); sendResponse(channel, remoteAddress, buf.getByte(buf.writerIndex() - 2)); if (type == MSG_POSITION_DATA || type == MSG_ROLLCALL_RESPONSE || type == MSG_ALARM_DATA || type == MSG_BLIND_AREA) { Position position = new Position(getProtocolName()); DeviceSession deviceSession = getDeviceSession(channel, remoteAddress, "1" + id, id); if (deviceSession == null) { return null; } position.setDeviceId(deviceSession.getDeviceId()); DateBuilder dateBuilder = new DateBuilder().setYear(BcdUtil.readInteger(buf, 2)) .setMonth(BcdUtil.readInteger(buf, 2)).setDay(BcdUtil.readInteger(buf, 2)) .setHour(BcdUtil.readInteger(buf, 2)).setMinute(BcdUtil.readInteger(buf, 2)) .setSecond(BcdUtil.readInteger(buf, 2)); position.setTime(dateBuilder.getDate()); position.setLatitude(BcdUtil.readCoordinate(buf)); position.setLongitude(BcdUtil.readCoordinate(buf)); position.setSpeed(UnitsConverter.knotsFromKph(BcdUtil.readInteger(buf, 4))); position.setCourse(BcdUtil.readInteger(buf, 4)); int flags = buf.readUnsignedByte(); position.setValid((flags & 0x80) != 0); position.set(Position.KEY_SATELLITES, flags & 0x0f); position.set(Position.KEY_STATUS, buf.readUnsignedByte()); position.set("key", buf.readUnsignedByte()); position.set("oil", buf.readUnsignedShort() / 10.0); position.set(Position.KEY_POWER, buf.readUnsignedByte() + buf.readUnsignedByte() * 0.01); position.set(Position.KEY_ODOMETER, buf.readUnsignedInt()); return position; } return null; } }