//  EchoApplication.java by Kari Laitinen

//  2012-12-21  Applet from http://www.frank-buss.de/echoservlet/index.html
//  2013-02-04  First working application.
//  2013-09-26  Last modification.

/*  Security problems prevented the running of the original applet.
    This Java application was created based on the applet

    This program can communicate with a Java Servlet that is 
    located in address "http://localhost:8080/EchoServlet/"

*/

import java.applet.Applet;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.net.*;

public class EchoApplication extends Frame implements WindowListener
{
   private TextField inputField = new TextField();
   private TextField outputField = new TextField();
   private TextArea exceptionArea = new TextArea();

   /**
    * Setup the GUI.
    */
   public EchoApplication()
   {
      setSize( 600, 400 ) ;

      setTitle( "EchoApplication" ) ;


      // set new layout
      setLayout( new GridBagLayout() ) ;


      // add title      
      Label title = new Label("Echo Application", Label.CENTER);
      title.setFont(new Font("SansSerif", Font.BOLD, 14));
      GridBagConstraints c = new GridBagConstraints();
      c.gridwidth = GridBagConstraints.REMAINDER;
      c.weightx = 1.0;
      c.fill = GridBagConstraints.HORIZONTAL;
      c.insets = new Insets(5, 5, 5, 5);
      add(title, c);

      // add input label, field and send button
      c = new GridBagConstraints();
      c.anchor = GridBagConstraints.EAST;
      add(new Label("Input:", Label.RIGHT), c);
      c = new GridBagConstraints();
      c.fill = GridBagConstraints.HORIZONTAL;
      c.weightx = 1.0;
      add(inputField, c);
      Button sendButton = new Button("Send");
      c = new GridBagConstraints();
      c.gridwidth = GridBagConstraints.REMAINDER;
      add( sendButton, c) ;

      sendButton.addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent e) {
            send_button_pressed();
         }
      });

      // add output label and non-editable field
      c = new GridBagConstraints();
      c.anchor = GridBagConstraints.EAST;
      add(new Label("Output:", Label.RIGHT), c);
      c = new GridBagConstraints();
      c.gridwidth = GridBagConstraints.REMAINDER;
      c.fill = GridBagConstraints.HORIZONTAL;
      c.weightx = 1.0;
      add(outputField, c);
      outputField.setEditable(false);

      // add exception label and non-editable textarea
      c = new GridBagConstraints();
      c.anchor = GridBagConstraints.EAST;
      add(new Label("Exception:", Label.RIGHT), c);
      c = new GridBagConstraints();
      c.gridwidth = GridBagConstraints.REMAINDER;
      c.weighty = 1;
      c.fill = GridBagConstraints.BOTH;
      add(exceptionArea, c);
      exceptionArea.setEditable(false);


      addWindowListener( this ) ;


   }

   /**
    * Get a connection to the servlet.
    */
   private URLConnection getServletConnection()
                               throws MalformedURLException, IOException
   {

      // Connection zum Servlet öffnen

      URL servlet_url = new URL( "http://localhost:8080/EchoServlet/");



      URLConnection url_connection = servlet_url.openConnection();

      // konfigurieren
      url_connection.setDoInput(true);
      url_connection.setDoOutput(true);
      url_connection.setUseCaches(false);
      url_connection.setRequestProperty( "Content-Type",
                              "application/x-java-serialized-object" ) ;

      // und zurückliefern
      return url_connection;
   }

   /**
    * Send the inputField data to the servlet
      and show the response from servlet in the outputField.
    */
   private void send_button_pressed()
   {
      try
      {
         // get input data for sending
         String text_to_send = inputField.getText();

         // send data to the servlet
         URLConnection url_connection = getServletConnection();
         OutputStream output_stream = url_connection.getOutputStream();
         ObjectOutputStream object_output_stream =
                                      new ObjectOutputStream( output_stream );

         object_output_stream.writeObject( text_to_send ) ;

         object_output_stream.flush() ;
         object_output_stream.close() ;

         // receive result from servlet
         InputStream input_stream = url_connection.getInputStream() ;

         ObjectInputStream object_input_stream =
                                        new ObjectInputStream( input_stream ) ;

         String text_from_servlet = (String) object_input_stream.readObject() ;

         object_input_stream.close() ;
         input_stream.close() ;

         // show result
         outputField.setText( text_from_servlet ) ;

      }
      catch ( Exception exception )
      {
         exception.printStackTrace() ;
         exceptionArea.setText( exception.toString() ) ;
      }
   }

   public void windowClosing( WindowEvent event )
   {
      setVisible( false ) ;
      System.exit( 0 ) ;
   }


   //  Other methods required by the WindowListener interface:

   public void windowActivated( WindowEvent event ) {}
   public void windowClosed( WindowEvent event ) {}
   public void windowDeactivated( WindowEvent event ) {}
   public void windowDeiconified( WindowEvent event ) {}
   public void windowIconified( WindowEvent event ) {}
   public void windowOpened( WindowEvent event ) {}



   public static void main( String[] command_line_arguments )
   {
      EchoApplication  this_application_window  =
                                new  EchoApplication() ;

      this_application_window.setVisible( true ) ;
   }

}