""" Day 100 - 知识体系梳理：设计模式综合示例 2 展示 OOP 三大特性 + 设计模式在实际场景中的应用 """ from abc import ABC, abstractmethod from typing import Dict, List, Optional from dataclasses import dataclass, field from enum import Enum import time # ============================================================ # 概念 1: 抽象基类 + 多态 + 继承（Day 33, 34, 49） # ============================================================ class PaymentMethod(ABC): """支付方式基类 - 抽象基类定义接口""" @abstractmethod def pay(self, amount: float) -> bool: """支付抽象方法""" pass @abstractmethod def refund(self, amount: float) -> bool: """退款抽象方法""" pass def process(self, amount: float, action: str = "pay") -> bool: """模板方法 - 固定流程""" print(f" 📋 处理{action}: ¥{amount:.2f}") if action == "pay": success = self.pay(amount) elif action == "refund": success = self.refund(amount) else: print(f" ❌ 未知操作: {action}") return False if success: print(f" ✅ {action}成功") else: print(f" ❌ {action}失败") return success # 多态：不同支付方式的实现 class CreditCard(PaymentMethod): """信用卡支付""" def __init__(self, card_number: str): self.card_number = card_number self.balance = 10000.0 def pay(self, amount: float) -> bool: if self.balance >= amount: self.balance -= amount print(f" 💳 信用卡 {self.card_number[-4:]} 扣款 ¥{amount:.2f}") return True return False def refund(self, amount: float) -> bool: self.balance += amount print(f" 💳 信用卡 {self.card_number[-4:]} 退款 ¥{amount:.2f}") return True class Alipay(PaymentMethod): """支付宝支付""" def __init__(self, account: str): self.account = account self.balance = 5000.0 def pay(self, amount: float) -> bool: if self.balance >= amount: self.balance -= amount print(f" 📱 支付宝 {self.account} 扣款 ¥{amount:.2f}") return True return False def refund(self, amount: float) -> bool: self.balance += amount print(f" 📱 支付宝 {self.account} 退款 ¥{amount:.2f}") return True # ============================================================ # 概念 2: 工厂模式 + 单例模式（Day 38） # ============================================================ class PaymentFactory: """支付工厂 - 根据类型创建支付对象""" _registry: Dict[str, type] = { "credit": CreditCard, "alipay": Alipay, } @classmethod def create(cls, method_type: str, **kwargs) -> PaymentMethod: """工厂方法""" if method_type not in cls._registry: raise ValueError(f"未知支付方式: {method_type}") payment_class = cls._registry[method_type] return payment_class(**kwargs) @classmethod def register(cls, name: str, payment_class: type): """注册新的支付方式""" cls._registry[name] = payment_class class OrderManager: """订单管理器 - 单例模式""" _instance = None def __new__(cls): if cls._instance is None: cls._instance = super().__new__(cls) cls._instance.orders = [] return cls._instance def create_order(self, payment: PaymentMethod, amount: float, description: str) -> bool: """创建订单并支付""" print(f"\n🛒 创建订单: {description} (¥{amount:.2f})") success = payment.process(amount, "pay") if success: self.orders.append({ "description": description, "amount": amount, "time": time.time(), }) return success # ============================================================ # 概念 3: 观察者模式 + 装饰器（Day 39, 23） # ============================================================ class EventSystem: """事件系统 - 观察者模式""" def __init__(self): self._listeners: Dict[str, List[callable]] = {} def on(self, event: str, callback: callable): """注册事件监听器""" if event not in self._listeners: self._listeners[event] = [] self._listeners[event].append(callback) print(f" 📡 注册监听器: {event} → {callback.__name__}") def emit(self, event: str, *args, **kwargs): """触发事件""" if event in self._listeners: print(f"\n 🎯 触发事件: {event}") for listener in self._listeners[event]: listener(*args, **kwargs) # 用装饰器记录事件日志 def log_event(func): """事件日志装饰器""" @functools.wraps(func) def wrapper(*args, **kwargs): print(f" 📝 记录事件: {func.__name__}") return func(*args, **kwargs) return wrapper # ============================================================ # 综合实战：电商订单系统 # ============================================================ import functools def timer(func): """计时装饰器""" @functools.wraps(func) def wrapper(*args, **kwargs): start = time.perf_counter() result = func(*args, **kwargs) elapsed = time.perf_counter() - start print(f" ⏱ {func.__name__} 耗时: {elapsed:.4f}s") return result return wrapper @timer def run_ecommerce_demo(): """ 综合演示：电商订单系统 融合了： - 抽象基类 + 多态 (Day 33, 34, 49) - 工厂模式 (Day 38) - 观察者模式 (Day 39) - 装饰器 (Day 23) - 单例模式 (Day 38) - 枚举 (Day 44) - dataclass (Day 43) """ print("=" * 60) print("🎓 Day 100 - 电商订单系统综合示例") print("=" * 60) # 1. 创建事件系统 event_system = EventSystem() def on_order_created(order_info): print(f" 📧 发送订单确认邮件: {order_info['description']}") def on_order_created_log(order_info): print(f" 📝 记录订单日志: {order_info['description']}") event_system.on("order_created", on_order_created) event_system.on("order_created", on_order_created_log) # 2. 创建订单管理器（单例） manager = OrderManager() # 3. 使用工厂创建支付方式 credit_card = PaymentFactory.create("credit", card_number="4111111111111234") alipay = PaymentFactory.create("alipay", account="user@example.com") # 4. 模拟订单流程 orders = [ ("Python 书籍", 99.0), ("机械键盘", 599.0), ("显示器支架", 199.0), ] for i, (desc, amount) in enumerate(orders): payment = credit_card if i % 2 == 0 else alipay success = manager.create_order(payment, amount, desc) if success: event_system.emit("order_created", {"description": desc, "amount": amount}) # 5. 查看所有订单 print("\n" + "=" * 60) print("📊 订单汇总") print("=" * 60) print(f" 总订单数: {len(manager.orders)}") total = sum(o['amount'] for o in manager.orders) print(f" 总金额: ¥{total:.2f}") # 6. 展示多态的威力 print("\n📌 多态演示：相同接口，不同实现") methods = [credit_card, alipay] for method in methods: print(f"\n {type(method).__name__}:") method.process(50, "pay") method.process(50, "refund") if __name__ == "__main__": run_ecommerce_demo()