[FEATURE] Tasklist Command #68

Author: Thidas Senavirathna

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

@@ -102,5 +102,6 @@ private static void registerCommands(Map<String, Command> commands) {
         commands.put("clearhistory", new ClearHistoryCommand());
         commands.put("alias", new AliasCommand());
         commands.put("unalias", new UnaliasCommand());
+        commands.put("tasklist", new TasklistCommand());
     }
 }

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

@@ -0,0 +1,78 @@
+package com.mycmd.commands;
+
+import com.mycmd.Command;
+import com.mycmd.ShellContext;
+
+import java.io.IOException;
+import java.lang.management.ManagementFactory;
+import java.lang.management.RuntimeMXBean;
+
+/**
+ * TasklistCommand - displays information about running processes.
+ * Usage: tasklist
+ *
+ * Notes:
+ * - Shows Java process information and system processes if available
+ * - Limited to what Java can access without platform-specific tools
+ */
+public class TasklistCommand implements Command {
+
+    @Override
+    public void execute(String[] args, ShellContext context) throws IOException {
+        System.out.println();
+        System.out.printf("%-40s %10s %15s%n", "Image Name", "PID", "Memory Usage");
+        System.out.println("=" .repeat(70));
+
+        // Get current Java process information
+        RuntimeMXBean runtimeMXBean = ManagementFactory.getRuntimeMXBean();
+        String jvmName = runtimeMXBean.getName();
+        String[] parts = jvmName.split("@");
+        String pid = parts.length > 0 ? parts[0] : "Unknown";
+
+        // Get memory info
+        Runtime runtime = Runtime.getRuntime();
+        long usedMemory = (runtime.totalMemory() - runtime.freeMemory()) / (1024 * 1024); // MB
+
+        System.out.printf("%-40s %10s %12s MB%n", "java.exe", pid, usedMemory);
+
+        // Try to get system processes using ProcessHandle (Java 9+)
+        try {
+            ProcessHandle.allProcesses()
+                .limit(20) // Limit to first 20 processes
+                .forEach(process -> {
+                    ProcessHandle.Info info = process.info();
+                    long processPid = process.pid();
+                    String command = info.command().orElse("Unknown");
+                    
+                    // Extract just the executable name from full path
+                    String execName = command;
+                    if (command.contains("/") || command.contains("\\")) {
+                        int lastSlash = Math.max(command.lastIndexOf('/'), command.lastIndexOf('\\'));
+                        execName = command.substring(lastSlash + 1);
+                    }
+                    
+                    // Truncate long names
+                    if (execName.length() > 40) {
+                        execName = execName.substring(0, 37) + "...";
+                    }
+                    
+                    System.out.printf("%-40s %10d %15s%n", execName, processPid, "N/A");
+                });
+        } catch (Exception e) {
+            // ProcessHandle not available or error accessing processes
+            System.out.println("\n[Additional process information not available]");
+        }
+
+        System.out.println();
+    }
+
+    @Override
+    public String description() {
+        return "Display a list of currently running processes.";
+    }
+
+    @Override
+    public String usage() {
+        return "tasklist";
+    }
+}