Assignment A4: Binary I/O

Assignment A4 (40 marks)
Focus: Binary I/O
Q1. [10 marks] Write a Java program to track how many times the program has been executed.
You can store an int representing the count in a file, e.g., count.dat. Each time your
program is executed, read the count, increment it by 1, and then store it back to the file. If
count.dat doesn’t exist (e.g., first time to run the program), store 1 in the file. Use binary
IO for your code. For this question, just write your code in the main method and declare the
checked exceptions in the method’s header.
Q2. [10 marks] Write a Hex Viewer method with the following header:
private static void viewHex(String filename)
The method reads bytes from filename and displays them in hex representation. The
output should be formatted as in the example below, i.e., each line consists of 8 pairs of hex
numbers, then ‘|’, then another 8 pairs. Use Integer.toHexString() to convert a
byte into a string representing the equivalent hex. Use a try statement to handle
IOException and display a simple error message if an I/O exception occurs.
Sample run (for the attached data.dat file)
Q3. [20 marks: 10 for each method]
Develop a class BackupRestore that has two static methods:
public static int backup(String filename, double partSize)
public static int restore(String filename, int numberOfPieces)
The backup method backs up huge files by splitting them into smaller pieces that may fit
into storage devices with different capacities (e.g., 700 mb for CD-Rs). The size of each piece
is equal to partSize megabytes. The method creates the output files filename.1,
filename.2, etc. and then returns an integer representing the number of files created.
The restore methods does the opposite. It combines filename.1, filename.2,
etc. into filename. The method returns an integer representing the total size of the file
filename.
In both methods, if an IOException occurs, display an error message and return -1. Use
buffer classes to improve performance.
Try your code on the course syllabus (syllabus.pdf), i.e., split it into pieces of e.g. 0.25 MB
size, delete the original file, and then combine your pieces back again and open the file to
see if your code works.
Bonus (5 marks): develop your code for Q3 once with a buffered I/O stream and once
without a buffer, and compare the results in terms of the time taken to backup and restore
the course syllabus. The output should be similar to the sample below:
Without a buffer:
Backing up...
Restoring...
Done in 48495 milliseconds.
With a buffer:
Backing up...
Restoring...
Done in 188 milliseconds.
Notes on the bonus:
a) Use System.currentTimeMillis() to measure the time taken by your methods
b) Don’t use input.getAvailable() method to check if you reached the end of the input file.
Instead, use another method for checking the end of file.
Grading
 15 % for logic explanation
 70 % for proper code structure and logic
 15 % for correct syntax and formatting

Submission Instructions
For programming questions, explain in few, simple sentences the algorithm you used to tackle
the problem. Add these sentences as a block comment at the beginning of your program. For
coding questions, make sure to use appropriate code formatting and structure (e.g., indentation,
brackets, etc.).
For this assignment, you need to do the following:
1- Create a Java project of which name consists of your student number followed by the
assignment number, e.g., “1234567_A2”.
2- Create one class for each question and write your answer inside that class. Your classes
should have the same name as the question number (e.g., Q1)
3- After solving all questions, open Windows Explorer (or any other file explorer).
4- Navigate to your Java project folder (can be found inside your Eclipse workspace folder).
5- Locate the “src” folder for this project (the folder that includes the source code for all
questions).
6- Zip the “src” folder and rename the zipped file to match your project name (e.g.,
1234567_A2.zip).
7- Submit the zipped file to Canvas.
Note that you can resubmit an assignment, but the new submission overwrites the old
submission and receives a new timestamp.