Java tutorial
/* * Copyright 2016 - 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.Context; 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.model.Position; import java.net.SocketAddress; import java.nio.charset.StandardCharsets; import java.util.ArrayList; import java.util.Date; import java.util.List; public class GranitProtocolDecoder extends BaseProtocolDecoder { private static final int HEADER_LENGTH = 6; private double adc1Ratio; private double adc2Ratio; private double adc3Ratio; private double adc4Ratio; public GranitProtocolDecoder(Protocol protocol) { super(protocol); adc1Ratio = Context.getConfig().getDouble("granit.adc1Ratio", 1); adc2Ratio = Context.getConfig().getDouble("granit.adc2Ratio", 1); adc3Ratio = Context.getConfig().getDouble("granit.adc3Ratio", 1); adc4Ratio = Context.getConfig().getDouble("granit.adc4Ratio", 1); } public static void appendChecksum(ByteBuf buffer, int length) { buffer.writeByte('*'); int checksum = Checksum.xor(buffer.nioBuffer(0, length)) & 0xFF; String checksumString = String.format("%02X", checksum); buffer.writeBytes(checksumString.getBytes(StandardCharsets.US_ASCII)); buffer.writeByte('\r'); buffer.writeByte('\n'); } private static void sendResponseCurrent(Channel channel, int deviceId, long time) { ByteBuf response = Unpooled.buffer(); response.writeBytes("BB+UGRC~".getBytes(StandardCharsets.US_ASCII)); response.writeShortLE(6); // length response.writeInt((int) time); response.writeShortLE(deviceId); appendChecksum(response, 16); channel.writeAndFlush(new NetworkMessage(response, channel.remoteAddress())); } private static void sendResponseArchive(Channel channel, int deviceId, int packNum) { ByteBuf response = Unpooled.buffer(); response.writeBytes("BB+ARCF~".getBytes(StandardCharsets.US_ASCII)); response.writeShortLE(4); // length response.writeShortLE(packNum); response.writeShortLE(deviceId); appendChecksum(response, 14); channel.writeAndFlush(new NetworkMessage(response, channel.remoteAddress())); } private void decodeStructure(ByteBuf buf, Position position) { short flags = buf.readUnsignedByte(); position.setValid(BitUtil.check(flags, 7)); if (BitUtil.check(flags, 1)) { position.set(Position.KEY_ALARM, Position.ALARM_GENERAL); } short satDel = buf.readUnsignedByte(); position.set(Position.KEY_SATELLITES, BitUtil.from(satDel, 4)); int pdop = BitUtil.to(satDel, 4); position.set(Position.KEY_PDOP, pdop); int lonDegrees = buf.readUnsignedByte(); int latDegrees = buf.readUnsignedByte(); int lonMinutes = buf.readUnsignedShortLE(); int latMinutes = buf.readUnsignedShortLE(); double latitude = latDegrees + latMinutes / 60000.0; double longitude = lonDegrees + lonMinutes / 60000.0; if (position.getValid()) { if (!BitUtil.check(flags, 4)) { latitude = -latitude; } if (!BitUtil.check(flags, 5)) { longitude = -longitude; } } position.setLongitude(longitude); position.setLatitude(latitude); position.setSpeed(buf.readUnsignedByte()); int course = buf.readUnsignedByte(); if (BitUtil.check(flags, 6)) { course = course | 0x100; } position.setCourse(course); position.set(Position.KEY_DISTANCE, buf.readShortLE()); int analogIn1 = buf.readUnsignedByte(); int analogIn2 = buf.readUnsignedByte(); int analogIn3 = buf.readUnsignedByte(); int analogIn4 = buf.readUnsignedByte(); int analogInHi = buf.readUnsignedByte(); analogIn1 = analogInHi << 8 & 0x300 | analogIn1; analogIn2 = analogInHi << 6 & 0x300 | analogIn2; analogIn3 = analogInHi << 4 & 0x300 | analogIn3; analogIn4 = analogInHi << 2 & 0x300 | analogIn4; position.set(Position.PREFIX_ADC + 1, analogIn1 * adc1Ratio); position.set(Position.PREFIX_ADC + 2, analogIn2 * adc2Ratio); position.set(Position.PREFIX_ADC + 3, analogIn3 * adc3Ratio); position.set(Position.PREFIX_ADC + 4, analogIn4 * adc4Ratio); position.setAltitude(buf.readUnsignedByte() * 10); int output = buf.readUnsignedByte(); for (int i = 0; i < 8; i++) { position.set(Position.PREFIX_IO + (i + 1), BitUtil.check(output, i)); } buf.readUnsignedByte(); // status message buffer } @Override protected Object decode(Channel channel, SocketAddress remoteAddress, Object msg) throws Exception { ByteBuf buf = (ByteBuf) msg; int indexTilde = buf.indexOf(buf.readerIndex(), buf.writerIndex(), (byte) '~'); DeviceSession deviceSession = getDeviceSession(channel, remoteAddress); if (deviceSession != null && indexTilde == -1) { String bufString = buf.toString(StandardCharsets.US_ASCII); Position position = new Position(getProtocolName()); position.setDeviceId(deviceSession.getDeviceId()); position.setTime(new Date()); getLastLocation(position, new Date()); position.setValid(false); position.set(Position.KEY_RESULT, bufString); return position; } if (buf.readableBytes() < HEADER_LENGTH) { return null; } String header = buf.readSlice(HEADER_LENGTH).toString(StandardCharsets.US_ASCII); if (header.equals("+RRCB~")) { buf.skipBytes(2); // binary length 26 int deviceId = buf.readUnsignedShortLE(); deviceSession = getDeviceSession(channel, remoteAddress, String.valueOf(deviceId)); if (deviceSession == null) { return null; } long unixTime = buf.readUnsignedIntLE(); if (channel != null) { sendResponseCurrent(channel, deviceId, unixTime); } Position position = new Position(getProtocolName()); position.setDeviceId(deviceSession.getDeviceId()); position.setTime(new Date(unixTime * 1000)); decodeStructure(buf, position); return position; } else if (header.equals("+DDAT~")) { buf.skipBytes(2); // binary length int deviceId = buf.readUnsignedShortLE(); deviceSession = getDeviceSession(channel, remoteAddress, String.valueOf(deviceId)); if (deviceSession == null) { return null; } byte format = buf.readByte(); if (format != 4) { return null; } byte nblocks = buf.readByte(); int packNum = buf.readUnsignedShortLE(); if (channel != null) { sendResponseArchive(channel, deviceId, packNum); } List<Position> positions = new ArrayList<>(); while (nblocks > 0) { nblocks--; long unixTime = buf.readUnsignedIntLE(); int timeIncrement = buf.getUnsignedShortLE(buf.readerIndex() + 120); for (int i = 0; i < 6; i++) { if (buf.getUnsignedByte(buf.readerIndex()) != 0xFE) { Position position = new Position(getProtocolName()); position.setDeviceId(deviceSession.getDeviceId()); position.setTime(new Date((unixTime + i * timeIncrement) * 1000)); decodeStructure(buf, position); position.set(Position.KEY_ARCHIVE, true); positions.add(position); } else { buf.skipBytes(20); // skip filled 0xFE structure } } buf.skipBytes(2); // increment } return positions; } return null; } }