Caesar Cipher - Java GUI

/***********************************************************************************
/ Name: Brian Butler
/ Professor: Gary Hartell
/ Date: May 5, 2011
/ Assignment: Final Project - Caesar Cipher
/								   
/					   		 Descripion:
/     This program uses the Caesar Cipher method of cryptography by shifting
/     letters of the alphabet by an amount chosen by the user (the key)
/     It also removes special characters, numbers and white spaces to make
/	   encryption more secure.
/
************************************************************************************/
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.Color.*;
import java.util.*;
import java.util.regex.*;//split strings
import javax.swing.border.*;//allows the use of borders

public class CaesarCipher extends JFrame
{					  
	private static JTextField inputKeyTF;
	
	private static JTextArea outputTA, inputTA;
	
	private JLabel headingL, encryptKeyL;
	
	private JScrollPane scrollText, scrollText2, scrollText3;//creates the scroll feature for JTextArea
														 
	private JButton encryptB,decryptB, exitB, clearB;

	private EncryptButtonHandler encrbHandler;
	private DecryptButtonHandler decryptHandler;
	private ExitButtonHandler ebHandler;
	private ClearButtonHandler clbHandler;	
	
	private static int WIDTH = 1035;
   private static int HEIGHT = 530;	
	
   public CaesarCipher()
	{
/************************************************************* Create borders    **/	        
	    Border raisedbevel, loweredbevel, blackline, compound;
		blackline = BorderFactory.createLineBorder(Color.black);    
		raisedbevel = BorderFactory.createRaisedBevelBorder();
          loweredbevel = BorderFactory.createLoweredBevelBorder();
		compound = BorderFactory.createCompoundBorder(loweredbevel, blackline);	
/************************************************************* Create Fonts     **/			
     Font font =  new Font("Courier New", Font.BOLD, 30);	
	  Font font2 = new Font("Times New Roman", Font.BOLD, 30);
	  Font font3 = new Font("Times New Roman", Font.BOLD, 26);
/************************************************************* Create labels    **/			
	  headingL = new JLabel("Enter your text below and a shift key,"+
	  " then click Encrypt or Decrypt",SwingConstants.CENTER);   	
	  encryptKeyL  = new JLabel("Enter a key between -25 and 25:");  
					  
	  inputTA = new  JTextArea("",50,895);
/*************** SET GRAY BACKGROUND IMAGE IN TEXT AREA ***************/ 
	  	final ImageIcon imageIcon = new ImageIcon("Caesar_cipher.png");
	inputTA = new JTextArea("",50,895) 
	{
      Image image = imageIcon.getImage();

      Image grayImage = GrayFilter.createDisabledImage(image);
      {
        setOpaque(false);
      }

      public void paint(Graphics g) {
        g.drawImage(grayImage, 0, 0, this);
        super.paint(g);
      }
    };//END SET BACKGROUND IMAGE
	  inputTA.setFont(font);
	  scrollText2 = new JScrollPane(inputTA);//adds the scroll feature to the outputTA
     scrollText2.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS); 
	  inputTA.setLineWrap(true);
     inputTA.setWrapStyleWord(true);
	
	  inputKeyTF = new JTextField(3);
	  inputKeyTF.setFont(font);
	
	  
	  outputTA = new JTextArea("",50,895);
	  outputTA.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));
	  	 /*************** SET GRAY BACKGROUND IMAGE IN TEXT AREA ***************/ 
	  	final ImageIcon imageIcon2 = new ImageIcon("encrypted.png");
	outputTA = new JTextArea("",50,895) 
	{
      Image image = imageIcon2.getImage();

      Image grayImage = GrayFilter.createDisabledImage(image);
      {
        setOpaque(false);
      }

      public void paint(Graphics g) {
        g.drawImage(grayImage, 0, 0, this);
        super.paint(g);
      }
    };//END SET BACKGROUND IMAGE
	 
	  outputTA.setFont(font);
	
	  scrollText = new JScrollPane(outputTA);//adds the scroll feature to the outputTA
     scrollText.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
	  outputTA.setLineWrap(true);
     outputTA.setWrapStyleWord(false);
	  outputTA.setEditable(false); 
		
	   encryptB = new JButton("Encrypt");
      encrbHandler = new EncryptButtonHandler();
      encryptB.addActionListener(encrbHandler);
	   encryptB.setFont(font2);
	 
	   decryptB = new JButton("Decrypt");
      decryptHandler = new DecryptButtonHandler();
      decryptB.addActionListener(decryptHandler);
	   decryptB.setFont(font2);
	 
	   exitB = new JButton("EXIT");
      ebHandler = new ExitButtonHandler();
      exitB.addActionListener(ebHandler);
	   exitB.setFont(font2);
	 
	   clearB = new JButton("Clear All");
      clbHandler = new ClearButtonHandler();
      clearB.addActionListener(clbHandler);
	   clearB.setFont(font2);	
	 
	   setTitle("The Caesar Cipher"); 
	              
      Container myWindow = getContentPane();
      myWindow.setLayout(null);
	 
	 	  decryptB.setLocation(750, 232);
	     encryptB.setLocation(540, 232);
		  exitB.setLocation(525, 453);
		  clearB.setLocation(250, 453);
		 
		  scrollText2.setLocation(5,52);
		  inputKeyTF.setLocation(465,233);
		  scrollText.setLocation(5,273);
					
        decryptB.setSize(200,40); 
		  encryptB.setSize(200,40); 
        exitB.setSize(225, 40);
		  clearB.setSize(225, 40);
		 
		  headingL.setSize(1010,40);
		  headingL.setLocation(5,5);
		  headingL.setFont(font2);
		  encryptKeyL.setSize(430,40);
		  encryptKeyL.setLocation(50,233);
		  encryptKeyL.setFont(font2);
		 
		  scrollText2.setSize(1010,180);
		  inputKeyTF.setSize(60,40);
		  scrollText.setSize(1010,180);
		  scrollText.setBorder(compound);
		  scrollText2.setBorder(compound);		 
		  
		  myWindow.add(decryptB);
		  myWindow.add(encryptB);          
        myWindow.add(exitB);
		  myWindow.add(clearB);
		  myWindow.add(headingL);
		  myWindow.add(encryptKeyL);
		  myWindow.add(scrollText2);
		  myWindow.add(inputKeyTF);
		  myWindow.add(scrollText);	
		  
	    setSize(WIDTH, HEIGHT);
        setVisible(true);
        setDefaultCloseOperation(EXIT_ON_CLOSE); 
 	  }
	  
	 private class EncryptButtonHandler implements ActionListener
    {//start encrypt button class
       public  void actionPerformed(ActionEvent e)       	 							
       {	 
           String sentence;
		     int key;		
 			 
 		   sentence = inputTA.getText();
		   sentence = sentence.toLowerCase();
		   sentence = sentence.replaceAll("[^a-zA-Z]+","");// removes all special characters
							                               //and numbers from the user's input
												           //to make encryption harder to hack 
											               // --To leave spaces between the words
												           //just leave a space after A-Z 	 
		try
		{
          key = Integer.parseInt(inputKeyTF.getText());
		    outputTA.setForeground(Color.blue);
      	 outputTA.setText("");
			 
		  if((key >=-25) &&(key<= 25))
		  {	
    	 		 char[] chars = sentence.toCharArray();  
  		
  			  for(int i = 0; i < sentence.length(); i++)
  			  {				
  					 char c = chars[i];				
		    	    char encrypted = encrypt(c, key);		  
           		 String output = Character.toString(encrypted);
				 
  /***** The output could have been simply output by using the string. The same
         way the DecryptButtonHandler output the text, but I was just practicing
	    with arrays so I did it as follows:                                 ****/					 
					 output.split("\\s");					 				
					 String[] outputArray = {output};
							
          	    for (int index=0; index < outputArray.length; index++)
	       	    {//NESTED FOR LOOP		 						      
          	        outputTA.append(outputArray[index]);//ENCRYPTED INPUT IS 
				   							            //DISPLAYED HERE  							 
		    	    }//end inside FOR LOOP	           					 
           }//end outside FOR	LOOP		 
        }
		
		  else
		  {
			   outputTA.setForeground(Color.red);
			   outputTA.setText("Key must be between -25 and 25!");
				inputKeyTF.setText("");			
				inputKeyTF.requestFocusInWindow();
			   
				key = Integer.parseInt(inputKeyTF.getText());
				
				
		  }
		 }//end try
		 	catch (NumberFormatException h)
			{
			   outputTA.setForeground(Color.red);
				outputTA.setText("Please enter a number between -25 and 25.");
				inputKeyTF.requestFocusInWindow();
			}
			catch (Exception j)
			{
			   outputTA.setForeground(Color.red);
				outputTA.setText("Please enter a number between -25 and 25.");
				inputKeyTF.requestFocusInWindow(); 
			}			
	 }
  }//END EncryptButtonHandler			
			
		public static char encrypt(char c, int key)/***** encrypt Method ******/
		{ 
           char[] alphabet = new char[26];
           int i = 0;
			  
           for(char ch = 'a'; ch <= 'z'; ++ch)//fills alphabet array with the alphabet
	        {
               alphabet[ch-'a']=ch;
           } 
			
   /********************** BELOW CODE FROM: ***********************/ 
	     //  http://www.cs.utsa.edu/~wagner/laws/Acaesar.html         
	  		
      			while (i < 26)
				   {      	 
         			 if (c == alphabet[i]) 
			 			 return alphabet[(i + key + 26)%26];
            		 i++;
      			}
     		      return c;
   /*************************************************************/
	   }	
      private class DecryptButtonHandler implements ActionListener
      {
           public  void actionPerformed(ActionEvent e)		    	 							
           {	 
               String sentence;
		         int key;		
 			 
 		         sentence = inputTA.getText();
			   		
	        try
			  {
         	   key = Integer.parseInt(inputKeyTF.getText());
					
				   outputTA.setForeground(Color.blue);
				   outputTA.setText("");
					
		         if((key >=-25) &&(key<= 25))
		         {			
    	              char[] chars = sentence.toCharArray();
		  
  			  for(int i = 0; i < sentence.length(); i++)
  			  {				
  					 char c = chars[i];				
		    	    char decrypted = decrypt(c, key);		  
           		 String output = Character.toString(decrypted);
					
           		 outputTA.append(output);//Decrypted Output					 
           }
					}
				 else
		  		 {
			   			outputTA.setForeground(Color.red);
			  			   outputTA.setText("Key must be between -25 and 25!");
							inputKeyTF.setText("");			
							inputKeyTF.requestFocusInWindow();
			   
							key = Integer.parseInt(inputKeyTF.getText());
				
				
		 		 }
			}//end try
		 	catch (NumberFormatException h)
			{
			   outputTA.setForeground(Color.red);
				outputTA.setText("Please enter a number between -25 and 25.");
				inputKeyTF.requestFocusInWindow();
			}
			catch (Exception j)
			{
			   outputTA.setForeground(Color.red);
				outputTA.setText("Please enter a number between -25 and 25.");
				inputKeyTF.requestFocusInWindow(); 
			}		
	   }
  }//END DecryptButtonHandler 

	public static char decrypt(char c, int key)/******* decrypt Method ************/
	{ 
      char[] alphabet = new char[26];
		int i = 0;
     
      for(char ch = 'a'; ch <= 'z'; ++ch)
	   {
          alphabet[ch-'a']=ch;//fills the array with the alphabet
      } 
      				
   /********************** BELOW CODE FROM: ***********************/ 
	//       http://www.cs.utsa.edu/~wagner/laws/Acaesar.html         
	  		
      			while (i < 26)
				   {      	 
         			 if (c == alphabet[i]) 
			 			 return alphabet[(i - key + 26)%26];
            		 i++;
      			}
     		      return c;
  }	
	 /*************************************************************/	

   private class ExitButtonHandler implements ActionListener
   {
       public void actionPerformed(ActionEvent e)
       {
           System.exit(0);//allows the exit button to close the JFrame window    
       }
    }// End of EXIT BUTTON actionPerformed   
	 
	 private class ClearButtonHandler implements ActionListener
    {
       public void actionPerformed(ActionEvent e)
       {
           inputTA.setText("");
			  outputTA.setText("");

			  inputKeyTF.setText("");
			  inputTA.requestFocusInWindow();
       }
    }    


   public static void main(String[] args)
   {	 
   
       CaesarCipher cipherObject = new CaesarCipher();		 
       cipherObject.setLocationRelativeTo(null);//lets the window popup in the 
									            //middle of the user's screen    
   }	
}
//END OF CODE

Below is a sample after text is entered and the encryption button is pressed - with a shift of 4

Below is a sample of the encrypted text from above and the decryption button is pressed - also with a shift of 4