TcpSocketメッセージの終了境界を検索する方法

import java.io.IOException;
import java.io.OutputStream;
public interface Framer {
    void frameMsg(byte[] message, OutputStream out) throws IOException;
    byte[] nextMsg() throws IOException;
}

デリミタベース(Delimiter-based)

import java.io.*;

public class DelimFramer implements Framer {

    private InputStream in;        // data source
    private static final byte DELIMITER = '
'; // message delimiter

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

    public void frameMsg(byte[] message, OutputStream out) throws IOException {
        // ensure that the message does not contain the delimiter
        for (byte b : message) {
            if (b == DELIMITER) {
                throw new IOException("Message contains delimiter");
            }
        }
        out.write(message);
        out.write(DELIMITER);
        out.flush();
    }

    public byte[] nextMsg() throws IOException {
        ByteArrayOutputStream messageBuffer = new ByteArrayOutputStream();
        int nextByte;

        // fetch bytes until find delimiter
        while ((nextByte = in.read()) != DELIMITER) {
            if (nextByte == -1) { // end of stream?
                if (messageBuffer.size() == 0) { // if no byte read
                    return null;
                } else { // if bytes followed by end of stream: framing error
                    throw new EOFException("Non-empty message without delimiter");
                }
            }
            messageBuffer.write(nextByte); // write byte to buffer
        }

        return messageBuffer.toByteArray();
    }
}

長さベース(Explicit length)

import java.io.*;

public class LengthFramer implements Framer {
    public static final int MAXMESSAGELENGTH = 65535;
    public static final int BYTEMASK = 0xff;
    public static final int SHORTMASK = 0xffff;
    public static final int BYTESHIFT = 8;

    private DataInputStream in; // wrapper for data I/O

    public LengthFramer(InputStream in) throws IOException {
        this.in = new DataInputStream(in);
    }

    public void frameMsg(byte[] message, OutputStream out) throws IOException {
        if (message.length > MAXMESSAGELENGTH) {
            throw new IOException("message too long");
        }
        // write length prefix
        out.write((message.length >> BYTESHIFT) & BYTEMASK);
        out.write(message.length & BYTEMASK);
        // write message
        out.write(message);
        out.flush();
    }

    public byte[] nextMsg() throws IOException {
        int length;
        try {
            length = in.readUnsignedShort(); // read 2 bytes
        } catch (EOFException e) { // , 
            return null;
        }
        // 0 <= length <= 65535
        byte[] msg = new byte[length];
        in.readFully(msg); // if exception, it's a framing error.
        return msg;
    }
}