Docs: Add Javadoc Comments to Public Methods in Command.java #9

Author: Thidas Senavirathna

src/main/java/com/mycmd/commands/CdCommand.java

@@ -4,6 +4,21 @@
 import com.mycmd.ShellContext;
 import java.io.File;
 
+/**
+ * Changes the current working directory or displays the current directory path.
+ * 
+ * This command allows navigation through the file system hierarchy. When called
+ * without arguments, it prints the absolute path of the current directory. When
+ * provided with a path argument, it attempts to change to that directory.
+ * 
+ * Usage:
+ * - cd          : Display current directory
+ * - cd path     : Change to specified path (absolute or relative)
+ * - cd ..       : Navigate to parent directory
+ * 
+ * The command handles both absolute and relative paths. Relative paths are
+ * resolved against the current working directory stored in ShellContext.
+ */
 public class CdCommand implements Command {
     @Override
     public void execute(String[] args, ShellContext context) {

src/main/java/com/mycmd/commands/ClsCommand.java

@@ -3,6 +3,17 @@
 import com.mycmd.Command;
 import com.mycmd.ShellContext;
 
+/**
+ * Clears the console screen by printing multiple blank lines.
+ * 
+ * This command simulates clearing the terminal screen by outputting 50 blank
+ * lines, pushing previous content out of view. This is a simple cross-platform
+ * approach that doesn't rely on terminal-specific control sequences.
+ * 
+ * Usage: cls
+ * 
+ * Note: This command does not accept any arguments.
+ */
 public class ClsCommand implements Command {
     @Override
     public void execute(String[] args, ShellContext context) {

src/main/java/com/mycmd/commands/ColorCommand.java

@@ -3,6 +3,22 @@
 import com.mycmd.Command;
 import com.mycmd.ShellContext;
 
+/**
+ * Changes the console text and background colors using ANSI escape codes.
+ * 
+ * This command accepts a two-character hexadecimal code where the first digit
+ * represents the background color and the second digit represents the text color.
+ * Valid color codes are 0-9 and A-F (hexadecimal). When called without arguments,
+ * it resets colors to terminal defaults.
+ * 
+ * Usage:
+ * - color       : Reset to default colors
+ * - color XY    : Set background to X and text to Y (hex digits 0-F)
+ * 
+ * Example: color 0A sets black background with bright green text.
+ * 
+ * Note: Background and text colors cannot be the same value.
+ */
 public class ColorCommand implements Command {
     @Override
     public void execute(String[] args, ShellContext context) {

src/main/java/com/mycmd/commands/CopyCommand.java

@@ -4,6 +4,20 @@
 import com.mycmd.ShellContext;
 import java.io.*;
 
+/**
+ * Copies a file from source to destination location.
+ * 
+ * This command reads the contents of a source file and writes it to a
+ * destination file using buffered I/O streams for efficient copying. Both
+ * source and destination paths are resolved relative to the current working
+ * directory unless absolute paths are provided.
+ * 
+ * Usage: copy source destination
+ * 
+ * The command verifies that the source exists and is a regular file before
+ * attempting the copy operation. If the destination file already exists, it
+ * will be overwritten.
+ */
 public class CopyCommand implements Command {
     @Override
     public void execute(String[] args, ShellContext context) {

src/main/java/com/mycmd/commands/DelCommand.java

@@ -4,6 +4,19 @@
 import com.mycmd.ShellContext;
 import java.io.File;
 
+/**
+ * Deletes one or more files from the file system.
+ * 
+ * This command accepts one or more file names as arguments and attempts to
+ * delete each file. File paths are resolved relative to the current working
+ * directory. The command provides feedback for each file indicating whether
+ * the deletion was successful or if the file was not found.
+ * 
+ * Usage: del file1 [file2 file3 ...]
+ * 
+ * Note: This command only deletes files, not directories. Use rmdir for
+ * directory removal.
+ */
 public class DelCommand implements Command {
     @Override
     public void execute(String[] args, ShellContext context) {

src/main/java/com/mycmd/commands/DirCommand.java

@@ -4,6 +4,21 @@
 import com.mycmd.ShellContext;
 import java.io.File;
 
+/**
+ * Lists files and directories in the current working directory.
+ * 
+ * This command displays all files and subdirectories within the current
+ * directory. Directories are prefixed with angle brackets and "DIR" label,
+ * while files are displayed with spacing for alignment.
+ * 
+ * Usage: dir
+ * 
+ * Output format:
+ * - Directories: angle-bracket-DIR-angle-bracket followed by directory name
+ * - Files: Six spaces followed by file name
+ * 
+ * If the directory is empty or cannot be read, an appropriate message is displayed.
+ */
 public class DirCommand implements Command {
     @Override
     public void execute(String[] args, ShellContext context) {

src/main/java/com/mycmd/commands/EchoCommand.java

@@ -3,6 +3,19 @@
 import com.mycmd.Command;
 import com.mycmd.ShellContext;
 
+/**
+ * Displays text messages to the console output.
+ * 
+ * This command prints all provided arguments to standard output, joining
+ * multiple arguments with spaces. When called without arguments, it prints
+ * a blank line.
+ * 
+ * Usage:
+ * - echo         : Print a blank line
+ * - echo message : Print the message to console
+ * 
+ * Multiple words are automatically joined with spaces between them.
+ */
 public class EchoCommand implements Command {
     @Override
     public void execute(String[] args, ShellContext context) {

src/main/java/com/mycmd/commands/ExitCommand.java

@@ -3,6 +3,18 @@
 import com.mycmd.Command;
 import com.mycmd.ShellContext;
 
+/**
+ * Terminates the MyCMD shell application.
+ * 
+ * This command exits the shell by calling System.exit(0), which immediately
+ * terminates the JVM process with a success status code. A goodbye message
+ * is displayed before exiting.
+ * 
+ * Usage: exit
+ * 
+ * Note: This command does not accept any arguments and exits immediately
+ * without prompting for confirmation.
+ */
 public class ExitCommand implements Command {
     @Override
     public void execute(String[] args, ShellContext context) {

src/main/java/com/mycmd/commands/HelpCommand.java

@@ -4,6 +4,19 @@
 import com.mycmd.ShellContext;
 import java.util.Map;
 
+/**
+ * Displays a list of all available commands in the shell.
+ * 
+ * This command provides users with an overview of commands registered in
+ * the shell. It requires access to the command registry (Map) which is
+ * provided during construction. Each command name is printed on a separate
+ * line with a bullet point prefix.
+ * 
+ * Usage: help
+ * 
+ * The command iterates through all keys in the command registry and displays
+ * them in the order provided by the map's key set.
+ */
 public class HelpCommand implements Command {
     private final Map<String, Command> commands;
 

src/main/java/com/mycmd/commands/HostnameCommand.java

@@ -5,6 +5,19 @@
 import com.mycmd.Command;
 import com.mycmd.ShellContext;
 
+/**
+ * Displays the hostname of the current computer.
+ * 
+ * This command attempts to retrieve the system hostname using two methods:
+ * first by checking the COMPUTERNAME environment variable (Windows-specific),
+ * and if that fails, by using InetAddress.getLocalHost().getHostName().
+ * If both methods fail, it displays "Unknown Host".
+ * 
+ * Usage: hostname
+ * 
+ * Note: This command works best on Windows systems where the COMPUTERNAME
+ * environment variable is typically set.
+ */
 public class HostnameCommand implements Command {
     @Override
     public void execute(String[] args, ShellContext context) {