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.model.Command; public class KhdProtocolEncoder extends BaseProtocolEncoder { public static final int MSG_CUT_OIL = 0x39; public static final int MSG_RESUME_OIL = 0x38; private ByteBuf encodeCommand(int command, String uniqueId) { ByteBuf buf = Unpooled.buffer(); buf.writeByte(0x29); buf.writeByte(0x29); buf.writeByte(command); buf.writeShort(6); // size uniqueId = "00000000".concat(uniqueId); uniqueId = uniqueId.substring(uniqueId.length() - 8); buf.writeByte(Integer.parseInt(uniqueId.substring(0, 2))); buf.writeByte(Integer.parseInt(uniqueId.substring(2, 4)) + 0x80); buf.writeByte(Integer.parseInt(uniqueId.substring(4, 6)) + 0x80); buf.writeByte(Integer.parseInt(uniqueId.substring(6, 8))); buf.writeByte(Checksum.xor(buf.nioBuffer())); buf.writeByte(0x0D); // ending return buf; } @Override protected Object encodeCommand(Command command) { String uniqueId = getUniqueId(command.getDeviceId()); switch (command.getType()) { case Command.TYPE_ENGINE_STOP: return encodeCommand(MSG_CUT_OIL, uniqueId); case Command.TYPE_ENGINE_RESUME: return encodeCommand(MSG_RESUME_OIL, uniqueId); default: return null; } } }