encodingschemes.java

Encoder/Decoder – Java version

package encoder_decoder;
/* Imports the java.awt package classes. */
import java.awt.*;
/* Imports the java.nio.charset package classes. */
import java.nio.charset.Charset;
/* Imports the java.util package classes. */
import java.util.SortedMap;
import java.util.Map;
import java.util.Iterator;
import java.util.Collection;
import java.lang.Object;
import java.util.Enumeration;
/* Imports the java.awt.event package classes. */
import java.awt.event.*;
/* Imports the javax.swing package classes. */
import javax.swing.*;
import javax.swing.ButtonModel;
/*
class EncodingSchemes - This class creates a window that displays various encoding schemes.
 Fields:
   title - Creates a title label.
   ok - Creates a OK button.
   cancel - Creates a Cancel button.
   rb - Creates the radio button. 
   buttonPanel - Creates a panel for button.
   schemePanel - Creates a panel to display the encoding scheme.
   numberPanel - Creates a panel to display the number of encoding scheme.
   mainPanel - Creates a main panel.
   encodingScheme - Contains the encoding scheme.
   cs- Creates an object of the Charset class. 
   c - Creates an object of the Collection class.
   Methods:
   getSchemes() - This method is executed when the EncodingSchemes constructor loads.
   actionPerformed() - This method is invoked when an end user clicks any button of the EncodingSchemes window. 
*/
public class EncodingSchemes extends JDialog implements ActionListener
{
   /* Declares the object of the SortedMap class. */ 
   SortedMap sm;
   /* Declares the object of the JLabel class. */
   JLabel title;
   /* Declares the objects of the JButton class. */
   JButton ok;
   JButton cancel;
   /* Declares the object of the String class. */
   String temp;
   /* Declares the object of the ButtonGroup class. */
   ButtonGroup bg;
   /* Declares the object of the JRadioButton class. */
   JRadioButton rb;
   /* Declares the object of the Charset class. */
   Charset cs;
   /* Declares the object of the Collection class. */
   Collection c;
   /* Declares the objects of the JPanel class. */
   JPanel buttonPanel;
   JPanel schemePanel;
   JPanel numberPanel;
   JPanel mainPanel;
   JScrollPane s_pane;
   /* Declares the object of the Font class. */
   Font f;
   int s;
   public EncoderDecoder ed;
   /* Declares the object of the String class. */
   public static String encodingScheme = "UTF-16";
   /* Defines the default constructor of the EncodingSchemes class. */
   public EncodingSchemes(EncoderDecoder ed)
   { 
      this.ed = ed;
      /* Sets the title of the Encoding Schemes window. */
      setTitle("Encoding Schemes");
      /* Sets the size of the Encoding Schemes window. */
      setSize(280, 500);
      /* Sets the re-sizability of the Encoding Schemes window to false. */
      setResizable(false);
      /* Initializes the object of the ButtonGroup class. */ 
      bg=new ButtonGroup();
      /* Initializes the object of the Font class. */
      f=new Font("Verdana", Font.BOLD, 12);
      /* Initializes the objects of the JPanel class. */
      buttonPanel=new JPanel();
      schemePanel=new JPanel();
      numberPanel=new JPanel();
      mainPanel=new JPanel();
      /* Initializes the object of the JLabel class. */
      title = new JLabel("Select the Encoding Scheme");
      title.setFont(f);
      /* Initializes and sets the layout of the button panel to grid layout. */ 
      buttonPanel.setLayout(new GridLayout(1, 2));
      /* Initializes and sets the layout of the number panel to border layout. */
      numberPanel.setLayout(new BorderLayout());
      /* Initializes and sets the layout of the main panel to border layout. */
      mainPanel.setLayout(new BorderLayout());
      /* Initializes the objects of the JButton class. */
      ok=new JButton("OK");
      cancel=new JButton("Cancel");
      /* Adds the action listener events to the Ok and Cancel buttons. */
      ok.addActionListener(this);
      cancel.addActionListener(this);
      /* Calls the getSchemes() method. */ 
      getSchemes();
      /* Adds various swing components on the panels. */
      numberPanel.add(title, BorderLayout.NORTH);
      buttonPanel.add(ok);
      buttonPanel.add(cancel);
      mainPanel.add(numberPanel, BorderLayout.NORTH);
      mainPanel.add(s_pane, BorderLayout.CENTER);
      mainPanel.add(buttonPanel, BorderLayout.SOUTH);
      /* Adds the main panel to frame. */
      getContentPane().add(mainPanel);
      /*
      addWindowListener - It contains a windowClosing() method.
      windowClosing(): This method is called when the end user clicks the close button of the Window. 
      Parameter: we- Represents an object of the WindowEvent class.
      Return Value: NA
      */
      addWindowListener(new WindowAdapter()
      {
         public void windowClosing(WindowEvent we)
         {
            dispose();
         }
      }); 
   }
   /*
   getSchemes() - This method returns the selected encoding scheme.
   Parameter - NA
   Return Value - NA
   */
   public void getSchemes()
   {
      try
      {
         /* Retrieves the available character schemes. */
         sm=Charset.availableCharsets();
         /* Gets the size of sorted map object. */
         s=sm.size();
         /* Sets the layout of the schemePanel panel to the GridLayout. */
         schemePanel.setLayout(new GridLayout(s, 1));
         /* Retrieves the value from the sorted model object. */
         c=sm.values();
         /* Creates and initializes the object of the Iterator class. */
         Iterator i=c.iterator();
         while(i.hasNext())
         {
            temp = i.next().toString();
            /* Initializes the object of the JRadioButton class. */
            rb = new JRadioButton(temp);
            if(temp.equals("UTF-16"))
            {
               rb.setSelected(true);
            }
            /* Adds the radio button to the button group. */
            bg.add(rb);
            /* Adds the radio button group to the schemePanel panel. */
            schemePanel.add(rb);
            s_pane = new JScrollPane(schemePanel);
            }
         }catch(Exception e)
         {
            System.out.println(e); 
         }
      }
      /*
      actionPerformed() - This method is called when the end user clicks the any button.
      Parameters: ev – Represents an objects of the ActionEvent class that contains the details of the event.
      Return Value: NA
      */
      public void actionPerformed(ActionEvent ev)
      {
         /* This section is executed when the end user clicks the OK button. */
         if(ev.getSource()==ok)
         {
            /* Creates and initializes the object of the Enumeration class to 
            get the elements from the button group. */
            Enumeration enum=bg.getElements();
            while(enum.hasMoreElements())
            {
               JRadioButton button = (JRadioButton)enum.nextElement();
               /* Checks the status of a radio button. */
               if (button.isSelected())
               {
                  /* Retrieves the text from the radio button. */
                  encodingScheme = button.getText();
                  ed.schemeText.setText(encodingScheme);
               }
            }
            /* Disposes the window. */
            dispose();
         }
         /* This section is executed when the end user clicks the Cancel button. */
         else if(ev.getSource()==cancel)
         {
            /* Disposes the window. */
            dispose();
         }
   }
}