/** * 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 com.github.liyue2008.rpc.transport.netty; import com.github.liyue2008.rpc.transport.command.Command; import com.github.liyue2008.rpc.transport.command.Header; import io.netty.buffer.ByteBuf; import io.netty.channel.ChannelHandlerContext; import io.netty.handler.codec.ByteToMessageDecoder; import java.util.List; /** * @author LiYue * Date: 2019/9/23 */ public abstract class CommandDecoder extends ByteToMessageDecoder { private static final int LENGTH_FIELD_LENGTH = Integer.BYTES; @Override protected void decode(ChannelHandlerContext channelHandlerContext, ByteBuf byteBuf, List<Object> list) { if (!byteBuf.isReadable(LENGTH_FIELD_LENGTH)) { return; } byteBuf.markReaderIndex(); int length = byteBuf.readInt() - LENGTH_FIELD_LENGTH; if (byteBuf.readableBytes() < length) { byteBuf.resetReaderIndex(); return; } Header header = decodeHeader(channelHandlerContext, byteBuf); int payloadLength = length - header.length(); byte [] payload = new byte[payloadLength]; byteBuf.readBytes(payload); list.add(new Command(header, payload)); } protected abstract Header decodeHeader(ChannelHandlerContext channelHandlerContext, ByteBuf byteBuf) ; }