🔖 Comments added

src/main/java/org/rrajesh1979/demo/MyCheckSum.java

@@ -26,7 +26,12 @@
 import lombok.extern.slf4j.Slf4j;
 import picocli.CommandLine;
 
-@CommandLine.Command(name = "mychecksum", mixinStandardHelpOptions = true, version = "mychecksum 0.0.8", description = "Prints the checksum (MD5 by default) of a file to STDOUT.")
+/**
+ * @author rrajesh1979
+ * @version 0.0.9
+ * @since 2021-Jan-01
+ */
+@CommandLine.Command(name = "mychecksum", mixinStandardHelpOptions = true, version = "mychecksum 0.0.9", description = "Prints the checksum (MD5 by default) of a file to STDOUT.")
 @Slf4j
 public class MyCheckSum implements Callable<Integer> {
     @CommandLine.Parameters(index = "0", description = "The file whose checksum to calculate.")
@@ -35,6 +40,13 @@ public class MyCheckSum implements Callable<Integer> {
     @CommandLine.Option(names = { "-a", "--algorithm" }, description = "MD5, SHA-1, SHA-256, ...")
     private String algorithm = "MD5";
 
+    /**
+     * Main function to invoke the picocli framework.
+     * @param args the command line arguments.
+     *             The first argument is the file whose checksum to calculate.
+     *             The second argument is the algorithm to use.
+     *             The default algorithm is MD5.
+     */
     public static void main(String[] args) {
         int exitCode;
         log.info("Hello from MyCheckSum");
@@ -44,13 +56,26 @@ public static void main(String[] args) {
 
     }
 
+    /**
+     * Function invoked by picocli to calculate the checksum of a file.
+     * @return Integer 0 if successful.
+     * @throws Exception if the file is not found. or if the algorithm is not found.
+     */
     @Override
     public Integer call() throws Exception {
         String checkSum = getCheckSum(file);
         log.info("Checksum of file {}, is : {}", file.getName(), checkSum);
         return 0;
     }
 
+    /**
+     * Function to calculate the checksum of a file.
+     *
+     * @param file the file whose checksum to calculate
+     * @return String
+     * @throws IOException if the file is not found.
+     * @throws NoSuchAlgorithmException if the algorithm is not found.
+     */
     public String getCheckSum(File file) throws IOException, NoSuchAlgorithmException {
         byte[] fileContents = Files.readAllBytes(file.toPath());
         byte[] digest = MessageDigest.getInstance(algorithm).digest(fileContents);