Create an interface that allows a user to encrypt/decrypt text files using (minimally) 12 bit single-error-correcting Hamming codes. 12-bit error correcting codes allow an 8bit char to be sent. To send two chars – or a 16 bit Unicode value) you would need a 21-bit Hamming solution.

· Since Java applets can’t read from a file, this will be a Frame-based application. A frame is a window.

· Provide a GUI with a JTextArea in the (borderlayout) center.

· For output, read the user's file and convert chars into 8 bit ASCII code.  Put into 12 bit "array" with correction/parity bits.  Write these "arrays" of binary values to an output file and also display them in the textarea.

· For input, read your "arrays" of 12 bit Hamming codes from an input file.  Check/correct single bit errors. Write the characters to an output file and the also display text area.

Extra credit: Do Hamming 21 bit (or some other size) instead

As always, you should work on the individual pieces SEPARATELY, in case you can’t complete some parts. Here’s a work schedule:

1. Convert an (ASCII) text file into Hamming codes. (Do this as a black-screen application to start with, displaying output using println(…))

· Convert chars into a binary representation of their ASCII codes

· Pack these into the correct positions of a 12-bit array

· Fill the other bit positions with the Hamming parity bits

2. Try to read Hamming codes and convert back to chars. (Do this as a black-screen application to start with, displaying output using println(…))
3. If you are able to complete 1 and 2, then try to correct errors in the codes. . (Do this as a black-screen application to start with, displaying output using println(…))
4. Build an appropriate frame-based GUI that can open and display file contents into a textarea – this part can be done separately from 1, 2, and 3.
5. Put the parts you are able to get working together in a nice frame-based application.

There are lots of ways to do everything in java. Here’s a program which reads a file using a scanner and outputs the contents as strings to another (.txt) file:

import java.util.*;

import java.io.*;

public class FileCopy{

public static void main (String args[]){

String first;

Scanner input;

String FileName1=args[0];

String FileName2=args[1];

try{

BufferedWriter bw=new BufferedWriter(new FileWriter(FileName2));

FileInputStream fis=new FileInputStream(FileName1);

input=new Scanner(fis);

while(input.hasNext()){

first=input.nextLine();

bw.write (first);

bw.newLine();

System.out.println(first);//echo to screen as well

}

fis.close();

dos.close();

}//try

catch(IOException e){}

}}

Here’s the run and contents of the output.txt file

C:\PROGRA~1\JAVA\JDK15~1.0_0\BIN>java FileCopy input.txt output.txt

here is a

sample

input file

With several lines

C:\PROGRA~1\JAVA\JDK15~1.0_0\BIN>type output.txt

here is a

sample

input file

With several lines