Client Implementation

Listing 9.4 CustomClient.java (Complete Client code)

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import java.rmi.*;
import java.util.*;

//client implementation
public class CustomClient 
	extends JFrame{
	
  //instance variables
  private JLabel lblName,lblAge,lblItems;
  private JTextField txtName,txtAge;
  private JTextArea txtMessage;
  private JComboBox cboItems;
  private JButton btnSubmit;
  private CustomInterface server;
	
  //constructor
  public CustomClient(){
	super("Client Window");
	Container cp = getContentPane();
		
	JPanel 
	  topPanel = new JPanel(new GridLayout(3,2)),
	  centerPanel = new JPanel(new BorderLayout()),
	  btnPanel = new JPanel();
			
		
	lblName = new JLabel("Name");
	lblAge = new JLabel("Age");
	lblItems = new JLabel("Items");
		
	//text field for entering customer name.
	txtName = new JTextField(15);
		
	//text field for entering customer age.
	txtAge = new JTextField(5);
		
	//text area to show message
	txtMessage = new JTextArea(5,20);
	 
	 //button to submit.
	 btnSubmit = new JButton("Sumbit");
	 btnSubmit.addActionListener(new ButtonHandler());
	 	 
	try{
  	    //get a remote object
	    server = (CustomInterface)Naming.lookup("Server");
			
	    //get all the products sold by the company.
	    Vector list = server.getList();
	    cboItems = new JComboBox(list);
	  }catch(Exception ex){
	      txtMessage.setText(ex.getMessage());
	  }
		
	//add components to containers.
	topPanel.add(lblName);	topPanel.add(txtName);	
	topPanel.add(lblAge);	topPanel.add(txtAge);	
	topPanel.add(lblItems);	topPanel.add(cboItems);
	centerPanel.add(txtMessage);
	btnPanel.add(btnSubmit);
	cp.add(topPanel,BorderLayout.NORTH);
	cp.add(centerPanel);
	cp.add(btnPanel,BorderLayout.SOUTH);	

	//set the default close operation 
	this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

	//pack() causes the window to be sized to fit the 
	//preferred size and layouts of its subcomponents. 
	pack();

	//set the location of window
	setLocation(15,15);
	
	//Make the Window visible.
	show();
    }
	
   //main method	
   public static void main(String args[]){
	 new CustomClient();
    }
	
   //event handling class
   private class ButtonHandler 
	implements ActionListener{
		
	public void actionPerformed(ActionEvent ae){
	 	 
	   //get the name of customer
	   String name = txtName.getText();
	 	 
	   //get the age of customer
	   int age = Integer.parseInt(txtAge.getText());
	 	 
	   //get the selected product
	   String item = (String)cboItems.getSelectedItem();
	 	 
	   //create a new customer object
	   Customer cm = new Customer(name,age,item);
	   try{
	      //call remote method
	      String msg = server.submit(cm);
	 		 
	      //shows the message returned by the server
	       txtMessage.setText(msg);
	      }catch(Exception ex){
	 	txtMessage.setText(ex.getMessage());
	   }
     }
   }
}			

Explanation

The client creates a number of components and containers. The combo box is filled with a Vector returned by the remote getList() method. When a user clicks the submit button, a new Customer objects is created and passed to the submit() method of the remote object. When a non-remote object is passed to another machine, the JVM makes a copy and sends that copy across the network (see Figure 9.1).