import java.lang.System;
import java.net.ServerSocket;
import java.net.Socket;
import java.io.*;

public class ReverseServerApp {
  
  public static void main(String args[]){
    try{
      ServerSocket server = new ServerSocket(1234);
      int localPort = server.getLocalPort();
      System.out.println("Reverse Server is listening on port "+localPort+".");
      Socket client = server.accept();
      String destName = client.getInetAddress().getHostName();
      int destPort = client.getPort();
      System.out.println("Accepted connection to "+destName+" on port "+
destPort+".");
      BufferedReader inStream = new BufferedReader(
      new InputStreamReader(client.getInputStream()));
      DataOutputStream outStream =
        new DataOutputStream(client.getOutputStream());
      boolean finished = false;
      do {
        String inLine = inStream.readLine();
        System.out.println("Received: "+inLine);
        if(inLine.equalsIgnoreCase("quit")) finished=true;
        String outLine=new ReverseString(inLine.trim()).getString();
        for(int i=0;i<outLine.length();++i)
          outStream.write((byte)outLine.charAt(i));
        outStream.write(13);
        outStream.write(10);
        outStream.flush();
        System.out.println("Sent: "+outLine);
      } while(!finished);
      inStream.close();
      outStream.close();
      client.close();
      server.close();
    }catch (IOException ex){
      System.out.println("IOException occurred.");
    }
  }
}

class ReverseString {
  String s;

  public ReverseString(String in){
    int len = in.length();
    char outChars[] = new char[len];
    for(int i=0;i<len;++i)
      outChars[len-1-i]=in.charAt(i);
    s = String.valueOf(outChars);
  }
  
  public String getString(){
    return s;
  }
}