Java Code

• • Reply

  17 years ago

  by Roumen

  Roumen

  London, United Kingdom

  Joined 17 years ago

  Please help needed to complete assignment:
  For this question I need to develop a server which either returns the time of day in hours
  and minutes when the client sends a message to it, or echoes back the message that was sent. The
  server should also respond to a quit message from the client. I have been provided with a simple client
  class named Client in a project (attached below).  
  I have two tasks. First to read the code within the client class and understand what is happening;
  especially the method actionPerformed. Note that the client has three buttons which are
  used to communicate with the server.
  Next, develop a class Server which interacts with the client and either sends it the time of day
  or echoes the message that was sent, depending on what service the client requests. There are a
  number of important points to notice about this question.
  •It would be very useful if you have completed Exercise 2.3  (suppliedon request ) before doing this question.
  •Try and make your code have the same structure as that of Exercise 2.3 (supplied on request). I may  
  borrow a large amount of code from this project. We shall not penalise you if you do!
  •When the client quits, the server should close down.
  The code that creates the current time is
  Calendar c = Calendar.getInstance();
               int hours = c.get(Calendar.HOUROFDAY);
               int minutes = c.get(Calendar.MINUTE);
  where the class Calendar can be found in java.util (don’t forget to import this). You will also find the method substring found in the class String  useful when developing the server code.
  

  
  Thanks in advance
  

  
  CLIENT CODE:
  import java.awt.;
  import java.awt.event.;
  import java.io.;
  import java.net.;
  

  
  //Note that there is no error processing in this client
  //Note, also that the important part of the code is in actionPerformed
  //The interface is not the most elegant: the buttons are long!
  

  
  public class Client extends Frame implements ActionListener{
  

  
   private Button timeButton;        //Button pressed to get the current time
   private Button echoButton;        //Button for echoing the text sent
   private Button quitButton;        //Button for quitting the client, click this to exit.
                                     //When this button has been clicked the client will exit
                                     //and the server will close down
   private TextField toBeSent;       //Text to be sent for echoing
   private TextField displayBox;     //Text sent from server displayed here
  

  
   //Network and stream objects
   private Socket s;
   private InputStream is;
   private BufferedReader bf;
   private OutputStream os;
   private PrintWriter pw;
  

  
   public Client(String title) throws IOException{
      //Create a window
      super(title);
      //Create visual objects
      timeButton = new Button("Time");       //When clicked asks for the time
      echoButton = new Button("Echo");       //When clicked will echo text
      quitButton = new Button("Quit");       //When clicked will quit the client and shit down the server
      toBeSent = new TextField(36);          //No more than 36 characters to be sent
      displayBox = new TextField(36);        //No more than 36 characters to be displayed
      //Set layout manager
      this.setLayout(new GridLayout(7,1));
      //Add seven visual objects in rows (includes labels)
      add(new Label("Message to be sent"));
      add(toBeSent);
      add(new Label("Message from server"));
      add(displayBox);
      add(timeButton);
      add(echoButton);
      add(quitButton);
      //Register the window to listen to the button clicks
      timeButton.addActionListener(this);
      echoButton.addActionListener(this);
      quitButton.addActionListener(this);
      //Set up network connections
      s = new Socket("127.0.0.1",1024); //Uses port 1024 and student pc, server must use this port
      is = s.getInputStream();
      bf = new BufferedReader(new InputStreamReader(is));
      os = s.getOutputStream();
      pw = new PrintWriter(os, true);
   }
  

  
    public void actionPerformed(ActionEvent ae){ //Executed when one of the buttons is clicked
       //Gets the label of the button that has been clicked
       String buttonLabel = ae.getActionCommand();
       //Code uses simple application protocol of single upper case letter
       //either E, Q or T
       try{
          if(buttonLabel.equals("Time")){
             //Clear the toBeSent box
             toBeSent.setText("");
             //Asks for the time from server
             pw.println("T");
             //Gets the time returned from the server
             String time = bf.readLine();
             //Displays it
             displayBox.setText(time);
          }
          if (buttonLabel.equals("Echo")){
             //Server needs to echo text
             //Send echo text preceded by E
             pw.println("E"+toBeSent.getText());
             //Read echoed text sent back from server and display it
             String echoText = bf.readLine();
             displayBox.setText(echoText);
          }
          if (buttonLabel.equals("Quit")){
             //Client quits, send quit command to server
             pw.println("Q");
             System.exit(0); //Collapses the window
          }
       }
       catch(IOException io){System.out.println("Problems with client "+ io);}
    }
  

  
    public static void main(String[] args){
       try{
          //Set up window
          Client cl = new Client("TMA02 client");
          //Size of window 400 x 200 pixels
          cl.setSize(400,200);
          //Make the window visible
          cl.setVisible(true);
       }catch(IOException io){System.out.println("Problem setting up client");}
    }
  }
  

  
  SERVER CODE (not full - the one i need to fill in):
  import java.net.;
  import java.io.;
  import java.util.*;  //For Calendar
  

  
  public class Server {
  

  
   public static void main(String[] args){
  

  
   //First set up all the network objects, don't forget to use port 1024
  

  
   while(true){
  

  
      // Read a line from the client
  

  
      // Decode the line and carry out the processing required
      // This could be the time of day, an echo or quit, the latter
      // quits the loop
   }
   }
  }
  

  
  Please let me know if you need the code of the mentioned exersise code.
  Tanx ;-)
  

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• • Reply

  17 years ago

  by coolio

  Coolio

  a place, United States

  Joined 18 years ago

  um... what exactly do you need help with?
  

  
  if you have a specific question, ok -- but no one
  is going to do your assignment for you... people
  to have better things to do than your homework for
  you that you are too lazy to do and want to get an
  unearned grade for.

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• • Reply

  17 years ago

  by Roumen

  Roumen

  London, United Kingdom

  Joined 17 years ago

  Well Sir,
  On that site there is no any conditions of the one you have mentioned.
  I do not want to cheat - I just want to learn. I have tried quite hard, but my code comes with errors and I need to see working one to find out my mistake.
  For a Guru like you it will not be very big deal I suppose.
  If you want to help - I will apptreciate, If not - fine, may be some one else will!
  Ciao
  Roumen

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• • Reply

  17 years ago

  by coolio

  Coolio

  a place, United States

  Joined 18 years ago

  if you want to "learn", then post specific questions, don't
  ask someone to do your assignment for you, because that
  is cheating. i highly doubt you would just "look" at the
  assignment, then try and code from scratch by yourself,
  rather than simply thinking "hmm, cool. ok, might as well
  hand this in".

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