netty ByteBuf corruption

I am using ByteToMessageDecoder

decode(ChannelHandlerContext ctx, ByteBuf bytebuf, List<Object> out) {
...
}

I want to perform some validation on incoming bytebuffer and then send bytebuf.nioBuffer() to out

1. do i have to make a copy of the bytebuf.nioBuffer() and add to output. if so what is the best way to do it
2. if I just add bytebuf.nioBuffer() to output will there be a chance of corruption
3. best way to extract ByteBuffer from netty ByteBuf, are there any utils available

If not enough data to read the complete message then call the reset method.

You don't need to copy bytebuf. That is not good for performance.

public class MyComplexByteToMessageDecoder extends ByteToMessageDecoder {

    @Override
    protected void decode(ChannelHandlerContext ctx, ByteBuf byteBuf, List<Object> out) throws Exception {
        // Mark the current read position
        byteBuf.markReaderIndex();

        // Check if there are enough bytes to read the length field (e.g., 4 bytes for an integer length)
        if (byteBuf.readableBytes() < 4) {
            byteBuf.resetReaderIndex();
            return; // Not enough data to read the length field
        }

        // Read the length field
        int length = byteBuf.readInt();

        // Check if enough bytes are available to read the complete message
        if (byteBuf.readableBytes() < length) {
            byteBuf.resetReaderIndex();
            return; // Not enough data to read the complete message
        }

        // Read the complete message (assuming it is a byte array)
        byte[] messageBytes = new byte[length];
        byteBuf.readBytes(messageBytes);

        // Decode the message and add to the output list
        String message = new String(messageBytes); // Example: decoding as a string
        out.add(message);
    }
}