Merge branch 'main' into feat/help-command

Author: studentpiyush

src/main/java/com/mycmd/App.java

@@ -29,6 +29,8 @@ public static void main(String[] args) {
             if (command != null) {
                 try {
                     command.execute(cmdArgs, context);
+                    // Add to history after successful execution
+                    context.addToHistory(input);
                 } catch (Exception e) {
                     System.out.println("Error: " + e.getMessage());
                 }
@@ -59,5 +61,6 @@ private static void registerCommands(Map<String, Command> commands) {
         commands.put("time", new TimeCommand());
         commands.put("tree", new TreeCommand());
         commands.put("date", new DateCommand());
+        commands.put("history", new HistoryCommand());
     }
 }

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/ShellContext.java

@@ -1,12 +1,17 @@
 package com.mycmd;
 
 import java.io.File;
+import java.util.ArrayList;
+import java.util.List;
 
 public class ShellContext {
     private File currentDir;
+    private List<String> commandHistory;
+    private static final int MAX_HISTORY = 10;
 
     public ShellContext() {
         this.currentDir = new File(System.getProperty("user.dir"));
+        this.commandHistory = new ArrayList<>();
     }
 
     public File getCurrentDir() {
@@ -16,4 +21,17 @@ public File getCurrentDir() {
     public void setCurrentDir(File dir) {
         this.currentDir = dir;
     }
+
+    public List<String> getCommandHistory() {
+        return commandHistory;
+    }
+
+    public void addToHistory(String command) {
+        if (command != null && !command.trim().isEmpty()) {
+            commandHistory.add(command.trim());
+            if (commandHistory.size() > MAX_HISTORY) {
+                commandHistory.remove(0);
+            }
+        }
+    }
 }

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) {