Merge pull request #37 from thidaskaveesha/doc/command

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

Author: anshumanjadiya1102

src/main/java/com/mycmd/Command.java

@@ -1,5 +1,26 @@
 package com.mycmd;
 
+/**
+ * Represents a shell command that can be executed inside the MyCMD shell.
+ * Implementations perform their operation when {@link #execute(String[], ShellContext)} is called.
+ */
 public interface Command {
+    /**
+     * Execute the command.
+     *
+     * <p>Implementations should perform all output to standard output or use the provided
+     * {@link ShellContext} for interactions that depend on the shell state (for example,
+     * changing the current directory).</p>
+     *
+     * @param args    command-line style arguments passed to the command. May be empty but
+     *                will not be null.
+     * @param context current shell context containing state such as the current working
+     *                directory. Implementations may read and/or modify this context.
+     * @throws Exception if the command cannot complete successfully. The caller (shell)
+     *                   is responsible for catching and reporting exceptions.
+     *
+     * @implNote Common concrete commands include `date` and `time` which simply print the
+     * current date/time to standard output. See their implementations for formatting details.
+     */
     void execute(String[] args, ShellContext context);
 }

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/DateCommand.java

@@ -4,7 +4,20 @@
 import com.mycmd.ShellContext;
 import java.time.LocalDate;
 
+/**
+ * Command that prints the current date to standard output.
+ *
+ * <p>This command does not use the provided {@link ShellContext} but keeps the
+ * parameter to conform to the {@link Command} contract. The output is produced
+ * using {@link LocalDate#now()} and printed in ISO-8601 format (yyyy-MM-dd).</p>
+ */
 public class DateCommand implements Command {
+    /**
+     * Print the current date.
+     *
+     * @param args    ignored for this command; may be empty or contain unused tokens.
+     * @param context the current shell context; not used by this command.
+     */
     @Override
     public void execute(String[] args, ShellContext context) {
         System.out.println("The current date is: " + java.time.LocalDate.now());

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) {