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 org.traccar.BaseProtocolEncoder; import org.traccar.helper.Checksum; import org.traccar.helper.DataConverter; import org.traccar.model.Command; import java.nio.charset.StandardCharsets; import java.util.TimeZone; public class MeiligaoProtocolEncoder extends BaseProtocolEncoder { private ByteBuf encodeContent(long deviceId, int type, ByteBuf content) { ByteBuf buf = Unpooled.buffer(); buf.writeByte('@'); buf.writeByte('@'); buf.writeShort(2 + 2 + 7 + 2 + content.readableBytes() + 2 + 2); // message length buf.writeBytes(DataConverter.parseHex((getUniqueId(deviceId) + "FFFFFFFFFFFFFF").substring(0, 14))); buf.writeShort(type); buf.writeBytes(content); buf.writeShort(Checksum.crc16(Checksum.CRC16_CCITT_FALSE, buf.nioBuffer())); buf.writeByte('\r'); buf.writeByte('\n'); return buf; } @Override protected Object encodeCommand(Command command) { ByteBuf content = Unpooled.buffer(); switch (command.getType()) { case Command.TYPE_POSITION_SINGLE: return encodeContent(command.getDeviceId(), MeiligaoProtocolDecoder.MSG_TRACK_ON_DEMAND, content); case Command.TYPE_POSITION_PERIODIC: content.writeShort(command.getInteger(Command.KEY_FREQUENCY) / 10); return encodeContent(command.getDeviceId(), MeiligaoProtocolDecoder.MSG_TRACK_BY_INTERVAL, content); case Command.TYPE_ENGINE_STOP: content.writeByte(0x01); return encodeContent(command.getDeviceId(), MeiligaoProtocolDecoder.MSG_OUTPUT_CONTROL, content); case Command.TYPE_ENGINE_RESUME: content.writeByte(0x00); return encodeContent(command.getDeviceId(), MeiligaoProtocolDecoder.MSG_OUTPUT_CONTROL, content); case Command.TYPE_ALARM_GEOFENCE: content.writeShort(command.getInteger(Command.KEY_RADIUS)); return encodeContent(command.getDeviceId(), MeiligaoProtocolDecoder.MSG_MOVEMENT_ALARM, content); case Command.TYPE_SET_TIMEZONE: int offset = TimeZone.getTimeZone(command.getString(Command.KEY_TIMEZONE)).getRawOffset() / 60000; content.writeBytes(String.valueOf(offset).getBytes(StandardCharsets.US_ASCII)); return encodeContent(command.getDeviceId(), MeiligaoProtocolDecoder.MSG_TIME_ZONE, content); case Command.TYPE_REQUEST_PHOTO: return encodeContent(command.getDeviceId(), MeiligaoProtocolDecoder.MSG_TAKE_PHOTO, content); case Command.TYPE_REBOOT_DEVICE: return encodeContent(command.getDeviceId(), MeiligaoProtocolDecoder.MSG_REBOOT_GPS, content); default: return null; } } }