com.alibaba.rocketmq.shade.io.netty.handler.codec.FixedLengthFrameDecoder Maven / Gradle / Ivy
/*
* Copyright 2012 The Netty Project
*
* The Netty Project licenses this file to you 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 io.netty.handler.codec;
import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import java.util.List;
/**
* A decoder that splits the received {@link ByteBuf}s by the fixed number
* of bytes. For example, if you received the following four fragmented packets:
*
* +---+----+------+----+
* | A | BC | DEFG | HI |
* +---+----+------+----+
*
* A {@link FixedLengthFrameDecoder}{@code (3)} will decode them into the
* following three packets with the fixed length:
*
* +-----+-----+-----+
* | ABC | DEF | GHI |
* +-----+-----+-----+
*
*/
public class FixedLengthFrameDecoder extends ByteToMessageDecoder {
private final int frameLength;
/**
* Creates a new instance.
*
* @param frameLength the length of the frame
*/
public FixedLengthFrameDecoder(int frameLength) {
if (frameLength <= 0) {
throw new IllegalArgumentException(
"frameLength must be a positive integer: " + frameLength);
}
this.frameLength = frameLength;
}
@Override
protected final void decode(ChannelHandlerContext ctx, ByteBuf in, List