Java tutorial
/* * Copyright 2015 - 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.BitUtil; import org.traccar.helper.UnitsConverter; import org.traccar.model.CellTower; import org.traccar.model.Network; import org.traccar.model.Position; import java.net.SocketAddress; import java.util.Date; import java.util.LinkedList; import java.util.List; public class BceProtocolDecoder extends BaseProtocolDecoder { public BceProtocolDecoder(Protocol protocol) { super(protocol); } private static final int DATA_TYPE = 7; public static final int MSG_ASYNC_STACK = 0xA5; public static final int MSG_STACK_COFIRM = 0x19; public static final int MSG_TIME_TRIGGERED = 0xA0; public static final int MSG_OUTPUT_CONTROL = 0x41; public static final int MSG_OUTPUT_CONTROL_ACK = 0xC1; @Override protected Object decode(Channel channel, SocketAddress remoteAddress, Object msg) throws Exception { ByteBuf buf = (ByteBuf) msg; String imei = String.format("%015d", buf.readLongLE()); DeviceSession deviceSession = getDeviceSession(channel, remoteAddress, imei); if (deviceSession == null) { return null; } List<Position> positions = new LinkedList<>(); while (buf.readableBytes() > 1) { int dataEnd = buf.readUnsignedShortLE() + buf.readerIndex(); int type = buf.readUnsignedByte(); if (type != MSG_ASYNC_STACK && type != MSG_TIME_TRIGGERED) { return null; } int confirmKey = buf.readUnsignedByte() & 0x7F; while (buf.readerIndex() < dataEnd) { Position position = new Position(getProtocolName()); position.setDeviceId(deviceSession.getDeviceId()); int structEnd = buf.readUnsignedByte() + buf.readerIndex(); long time = buf.readUnsignedIntLE(); if ((time & 0x0f) == DATA_TYPE) { time = time >> 4 << 1; time += 0x47798280; // 01/01/2008 position.setTime(new Date(time * 1000)); // Read masks int mask; List<Integer> masks = new LinkedList<>(); do { mask = buf.readUnsignedShortLE(); masks.add(mask); } while (BitUtil.check(mask, 15)); mask = masks.get(0); if (BitUtil.check(mask, 0)) { position.setValid(true); position.setLongitude(buf.readFloatLE()); position.setLatitude(buf.readFloatLE()); position.setSpeed(UnitsConverter.knotsFromKph(buf.readUnsignedByte())); int status = buf.readUnsignedByte(); position.set(Position.KEY_SATELLITES, BitUtil.to(status, 4)); position.set(Position.KEY_HDOP, BitUtil.from(status, 4)); position.setCourse(buf.readUnsignedByte() * 2); position.setAltitude(buf.readUnsignedShortLE()); position.set(Position.KEY_ODOMETER, buf.readUnsignedIntLE()); } if (BitUtil.check(mask, 1)) { position.set(Position.KEY_INPUT, buf.readUnsignedShortLE()); } for (int i = 1; i <= 8; i++) { if (BitUtil.check(mask, i + 1)) { position.set(Position.PREFIX_ADC + i, buf.readUnsignedShortLE()); } } if (BitUtil.check(mask, 10)) { buf.skipBytes(4); } if (BitUtil.check(mask, 11)) { buf.skipBytes(4); } if (BitUtil.check(mask, 12)) { buf.skipBytes(2); } if (BitUtil.check(mask, 13)) { buf.skipBytes(2); } if (BitUtil.check(mask, 14)) { position.setNetwork(new Network(CellTower.from(buf.readUnsignedShortLE(), buf.readUnsignedByte(), buf.readUnsignedShortLE(), buf.readUnsignedShortLE(), buf.readUnsignedByte()))); buf.readUnsignedByte(); } if (BitUtil.check(mask, 0)) { positions.add(position); } } buf.readerIndex(structEnd); } // Send response if (type == MSG_ASYNC_STACK && channel != null) { ByteBuf response = Unpooled.buffer(8 + 2 + 2 + 1); response.writeLongLE(Long.parseLong(imei)); response.writeShortLE(2); response.writeByte(MSG_STACK_COFIRM); response.writeByte(confirmKey); int checksum = 0; for (int i = 0; i < response.writerIndex(); i++) { checksum += response.getUnsignedByte(i); } response.writeByte(checksum); channel.writeAndFlush(new NetworkMessage(response, remoteAddress)); } } return positions; } }