자바로 작성하는 기초 채팅 프로그램(핸들러)

import java.net.*;
import java.io.*;

class ChatHandler extends Thread {

	private ChatServer cs;
	private Socket so;
	private BufferedReader br;
	private PrintWriter pw;

	public ChatHandler(ChatServer cs, Socket so) throws IOException {
		this.cs = cs;
		this.so = so;
		br = new BufferedReader(new InputStreamReader(so.getInputStream()));
		pw = new PrintWriter(new BufferedWriter(new OutputStreamWriter(
				so.getOutputStream())));
	}

	public void run() {
		String name = null;
		try {
			name = br.readLine();
			cs.register(this); // 벡터에 등록
			cs.broadcast(name + "님이 입장하셨습니다...");

			while (true) {
				String data = br.readLine();
				if (data == null || data.toLowerCase().equals("quit"))
					break;

				cs.broadcast("[" + name + "]" + data);
			}
		} catch (IOException io) {
			io.printStackTrace();
		}

		// -------------

		cs.unregister(this); // 벡테에서 제거
		cs.broadcast(name + "님이 퇴장하셨습니다..");
		try {
			br.close();
			pw.close();
			so.close();
		} catch (IOException io) {
			io.printStackTrace();
		}
	}

	public PrintWriter getPrintWriter() {
		return pw;
	}
}