//FIg17.6 - server.java
   //configura um servidor que ira receber pacotes de um cliente e enviar-lhe pacotes

   import java.io.*;
   import java.net.*;
   import java.awt.*;
   import java.awt.event.*;
   import java.util.*;

   import javax.swing.*;

   public class Server1 extends JFrame
   {
      private JTextArea displayArea;
      private DatagramPacket sendPacket, receivePacket;
      private DatagramSocket socket;

      public Server1()
      {
         super("Server");

         displayArea = new JTextArea();
         getContentPane().add(new JScrollPane (displayArea), BorderLayout.CENTER);
         setSize (400,300);
         setVisible(true);

         //cria DatagramSocket para enviar e receber pacotes
         try
         {
            socket = new DatagramSocket(5000);
         }
         catch (SocketException socketException)
         {
            socketException.printStackTrace();
            System.exit(1);
         }
      }

      //espera que os pacotes cheguem e, depois, exibe os dados e ecoa o pacote p/ o cliente
      public void waitForPackets()
      {
         while (true)
         {
            //recebe o pacote, exibe o conteudo e ecoa p/ o cliente
            try
            {
               byte data[] = new byte[100];
               receivePacket = new DatagramPacket (data,data.length);

               //espera o pacote
               socket.receive (receivePacket);

               //processa o pacote
               displayPacket();

               //ecoa as informacoes do pacote de volta p/ o cliente
               sendPacketToClient();
            }
            catch (IOException ioException)
            {
               displayArea.append(ioException.toString() + "\n");
               ioException.printStackTrace();
            }
         }
      }

      //exibe conteudo do pacote
      private void displayPacket()
      {

         //� aqui que os dados sao recebidos em bytes, convertidos p/ string e jogados nos
         //seus campos pelo Token
         String SNome="",SData="",SHora="";
         String dados = new String(receivePacket.getData(),0,receivePacket.getLength());
         String auxToken = "";
         int iCont=0;
         StringTokenizer tokens = new StringTokenizer(dados);

         while (tokens.hasMoreTokens())
         {

            SNome = tokens.nextToken();
            SData = tokens.nextToken();
            SHora = tokens.nextToken();

         }
         displayArea.append("Nome: " + SNome +"\nData: " + SData + "\nHora: " + SHora);

         /*displayArea.append("\n Packet received: " +
                        "\nFrom host : " + receivePacket.getAddress() +
                        "\nHost port : " + receivePacket.getPort() +
                        "\nLength    : " + receivePacket.getLength() +
                        "\nContaining: \n\t" + auxToken);*/


      }


      //ecoa pacote p/ o cliente
      private void sendPacketToClient() throws IOException
      {
         displayArea.append("\n\nEcho data to client...");

         //cria pacote p/ enviar
         /*sendPacket = new DatagramPacket(receivePacket.getData(),
                                 receivePacket.getLength(),
                                 receivePacket.getAddress(),
                                 receivePacket.getPort());
         //envia o pacote
         socket.send(sendPacket);*/

         String message = "MENSAGEM ENTREGUE COM SUCESSO!!!";//event.getActionCommand();
           byte data[] = message.getBytes();
         sendPacket = new DatagramPacket(data,data.length,receivePacket.getAddress(),receivePacket.getPort());
         socket.send(sendPacket);

         displayArea.append("Packet sent\n\n================================");
         displayArea.setCaretPosition(displayArea.getText().length());
      }

      //executa o aplicativo
      public static void main (String args[])
      {
         Server1 application = new Server1();
         application.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
         application.waitForPackets();
      }
   }



   // Fig. 17.7: Client.java
   // Set up a Client that will send packets to a
   // server and receive packets from a server.

   // Java core packages
   import java.io.*;
   import java.net.*;
   import java.awt.*;
   import java.awt.event.*;
   import java.util.*;

   // Java extension packages
   import javax.swing.*;

   public class Client1 extends JFrame {
      private JTextField enterField;
      private JTextArea displayArea;
      private DatagramPacket sendPacket, receivePacket;
      private DatagramSocket socket;

      // set up GUI and DatagramSocket
      public Client1()
      {
         super( "Client" );

         Container container = getContentPane();

         enterField = new JTextField( "   " );

         enterField.addActionListener(

            new ActionListener() {

               // create and send a packet
               public void actionPerformed( ActionEvent event )
               {
                  // create and send packet
                  try
               {
                     displayArea.append("\nSending packet containing: " + event.getActionCommand() + "\n" );

                     // get message from textfield and convert to
                     // array of bytes
                     String Nome="Bruno",Hora="15:30";
                 String Data="14/02/1982";
                 String message = /*event.getActionCommand()+*/ Nome + " " + Data + " "+ Hora;
                     byte data[] = message.getBytes();

                 //TOKENS
                 /*String stringToTokenize = event.getActionCommand();
                 StringTokenizer tokens = new StringTokenizer(stringToTokenize);*/

                     // create sendPacket
                     sendPacket = new DatagramPacket(data,data.length, InetAddress.getByName("localhost"), 5000 );

                     // send packet
                     socket.send( sendPacket );

                     displayArea.append( "Packet sent\n" );
                     displayArea.setCaretPosition(displayArea.getText().length() );
                  }

                  // process problems creating or sending packet
                  catch ( IOException ioException ) {
                     displayArea.append(
                        ioException.toString() + "\n" );
                     ioException.printStackTrace();
                  }

               }  // end actionPerformed

            }  // end anonymous inner class

         ); // end call to addActionListener

         container.add( enterField, BorderLayout.NORTH );

         displayArea = new JTextArea();
         container.add( new JScrollPane( displayArea ), BorderLayout.CENTER );

         setSize( 400, 300 );
         setVisible( true );

         // create DatagramSocket for sending and receiving packets
         try
        {
            socket = new DatagramSocket();
         }

         // catch problems creating DatagramSocket
         catch( SocketException socketException )
        {
            socketException.printStackTrace();
            System.exit( 1 );
         }

      }  // end Client constructor

      // wait for packets to arrive from Server,
      // then display packet contents
      public void waitForPackets()
      {
         // loop forever
         while ( true )
        {
            // receive packet and display contents
            try
           {

               // set up packet
               byte data[] = new byte[ 100 ];
               receivePacket = new DatagramPacket( data, data.length );

               // wait for packet
               socket.receive( receivePacket );

               // display packet contents
               displayPacket();
            }

            // process problems receiving or displaying packet
            catch( IOException exception )
          {
               displayArea.append( exception.toString() + "\n" );
               exception.printStackTrace();
            }

         }  // end while

      }  // end method waitForPackets

      // display contents of receivePacket
      private void displayPacket()
      {
         displayArea.append( "\nPacket received:" +
            "\nFrom host: " + receivePacket.getAddress() +
            "\nHost port: " + receivePacket.getPort() +
            "\nLength: " + receivePacket.getLength() +
            "\nContaining:\n\t" +
            new String( receivePacket.getData(), 0, receivePacket.getLength() ) );

         displayArea.setCaretPosition(displayArea.getText().length() );
      }

      // execute application
      public static void main( String args[] )
      {
         Client1 application = new Client1();

         application.setDefaultCloseOperation(
            JFrame.EXIT_ON_CLOSE );

         application.waitForPackets();
      }

   }  // end class Client