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

class SocketProxy implements SocketInterface {
  // 1. Create a "wrapper" for a remote,
  // or expensive, or sensitive target
  private Socket      socket;
  private BufferedReader in;
  private PrintWriter   out;

  public SocketProxy( String host, int port, boolean wait ) {
    try {
      if (wait) {
        // 2. Encapsulate the complexity/overhead of the target in the wrapper
        ServerSocket server = new ServerSocket( port );
        socket = server.accept();
      } else
        socket = new Socket( host, port );
        in  = new BufferedReader( new InputStreamReader(
                                        socket.getInputStream()));
        out = new PrintWriter( socket.getOutputStream(), true );
      } catch( IOException e ) {
        e.printStackTrace();
      }
  }
  public String readLine() {
    String str = null;
    try {
      str = in.readLine();
    } catch( IOException e ) {
      e.printStackTrace();
    }
    return str;
  }
  public void writeLine( String str ) {
    // 4. The wrapper delegates to the target
    out.println( str );
  }
  public void dispose() {
    try {
      socket.close();
    } catch( IOException e ) {
      e.printStackTrace();
    }
  }
}