update Functions-DecoratorPattern

Author: rambasnet

notebooks/Functions-DecoratorPattern.ipynb

@@ -1922,14 +1922,124 @@
     "test2(1, 9, 2)"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "id": "21db9ece",
+   "metadata": {},
+   "source": [
+    "### Defining class decorator\n",
+    "\n",
+    "- in the following example; we have an original class Coffee\n",
+    "- MilkDecorator decorates Coffee by adding cost of milk\n",
+    "- similarly, Coffee can be wrapped with more decorators (e.g., SugarDecorator, WhippedCreamDecorator, etc.)\n",
+    "- this decorator pattern utilizes the **Open-Closed Principle (OCP) of SOLID** principles\n",
+    "    - making it easy to extend functionality without modifying the original class"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 1,
+   "id": "8f9d7fed",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "class Coffee:\n",
+    "    def cost(self):\n",
+    "        return 5\n",
+    "    \n",
+    "\n",
+    "#Decorator class\n",
+    "class MilkDecorator:\n",
+    "    def __init__(self, coffee):\n",
+    "        self._coffee = coffee\n",
+    "    \n",
+    "    def cost(self):\n",
+    "        return self._coffee.cost() + 2 # Add cost of mile"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 4,
+   "id": "04756de0",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Black Coffee Cost: 5\n"
+     ]
+    }
+   ],
+   "source": [
+    "# without using the decorator\n",
+    "black_coffee  = Coffee()\n",
+    "print(\"Black Coffee Cost:\", black_coffee.cost())"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 7,
+   "id": "f39a53d3",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Milk Coffee Cost: 7\n"
+     ]
+    }
+   ],
+   "source": [
+    "# using the decorator\n",
+    "milk_coffee = MilkDecorator(black_coffee)\n",
+    "print(\"Milk Coffee Cost:\", milk_coffee.cost())"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 8,
+   "id": "b960c48d",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "class SugarDecorator:\n",
+    "    def __init__(self, coffee):\n",
+    "        self._coffee = coffee\n",
+    "\n",
+    "    def cost(self):\n",
+    "        return self._coffee.cost() + 1  # Add cost of sugar"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 9,
+   "id": "07ec20c5",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "Coffee with Milk and Sugar Cost: 8\n"
+     ]
+    }
+   ],
+   "source": [
+    "# Applying multiple decorators\n",
+    "coffee_with_milk_and_sugar = SugarDecorator(MilkDecorator(Coffee()))\n",
+    "print(\"Coffee with Milk and Sugar Cost:\", coffee_with_milk_and_sugar.cost())"
+   ]
+  },
   {
    "cell_type": "code",
    "execution_count": 29,
    "id": "063ef55e",
    "metadata": {},
    "outputs": [],
    "source": [
-    "# class decorators\n",
+    "# Useful class decorators example\n",
     "# Generates demo.log when applied to a function\n",
     "# __call__ overrides when the class is called like a function\n",
     "\n",