JavaのTCP/IPプログラミング学習--デリミタベースのフレーム化

package framer;

import java.io.IOException;
import java.io.OutputStream;

public interface Framer {
    /**
     *                   
     * @param message
     * @param out
     * @throws IOException
     */
    void frameMsg(byte[] message, OutputStream out) throws IOException;

    /**
     *       ，         
     * @return
     * @throws IOException
     */
    byte[] nextMsg() throws IOException;
}

package framer;

import java.io.*;

/**
 * @ClassName DelimFramer
 * @Description TODO
 * @Author Cays
 * @Date 2019/3/16 22:04
 * @Version 1.0
 **/
public class DelimFramer implements Framer {
    //   
    private InputStream in;
    //       
    private static final byte DELIMITER='
';

    public DelimFramer(InputStream in) {
        this.in = in;
    }

    @Override
    public void frameMsg(byte[] message, OutputStream out) throws IOException {
        //            
        for (byte b:message){
            if (b==DELIMITER){
                throw new IOException("Message contaions delimiter");
            }
        }
        //           
        out.write(message);
        //     
        out.write(DELIMITER);
        out.flush();
    }

    @Override
    public byte[] nextMsg() throws IOException {
        ByteArrayOutputStream messageBuffer=new ByteArrayOutputStream();
        int nextByte;
        //          ，       
        while ((nextByte=in.read())!=DELIMITER){
            if (nextByte==-1){
                //                
                if (messageBuffer.size()==0){
                    return null;
                }else {
                    //            ，    
                    throw new EOFException("Non-empty message without delimiter");
                }
            }
            //               
            messageBuffer.write(nextByte);
        }
        //                   
        return messageBuffer.toByteArray();
    }
}