update:demo9

com/study/demo9/PermissionSystem.java

@@ -0,0 +1,40 @@
+package com.study.demo9;
+
+
+public class PermissionSystem {
+    public static void main(String[] args) {
+        User admin = new User("admin", "admin");
+        User guest = new User("guest", "guest");
+
+        System.out.println("Admin can delete: " + admin.checkPermission("delete"));
+        System.out.println("Admin can read: " + admin.checkPermission("read"));
+        System.out.println("Guest can read: " + guest.checkPermission("read"));
+        System.out.println("Guest can delete: " + guest.checkPermission("delete"));
+    }
+}
+
+class User {
+    private String username;
+    private String role;
+
+    public User(String username, String role) {
+        this.username = username;
+        this.role = role;
+    }
+
+    public boolean checkPermission(String operation) {
+        PermissionChecker checker = new PermissionChecker();
+        return checker.hasPermission(operation);
+    }
+
+    class PermissionChecker {
+        boolean hasPermission(String operation) {
+            if ("admin".equals(role)) {
+                return true;
+            } else if ("guest".equals(role)) {
+                return "read".equals(operation);
+            }
+            return false;
+        }
+    }
+}