我们将使用责任链模式和装饰者模式的组合。

考虑一个简化的餐厅订单处理系统，其中包括服务员（Waiter）、厨师（Chef）和收银员（Cashier）。订单从服务员开始，然后传递给厨师，最后到达收银员。订单对象包含了顾客的点菜信息。

订单类（Order）：

public class Order {private String customerName;private String dishName;public Order(String customerName, String dishName) {this.customerName = customerName;this.dishName = dishName;}public String getCustomerName() {return customerName;}public String getDishName() {return dishName;}
}

责任链模式：服务员、厨师和收银员

// 处理订单的接口
public interface OrderHandler {void handleOrder(Order order);
}// 服务员
public class Waiter implements OrderHandler {private OrderHandler nextHandler;public Waiter(OrderHandler nextHandler) {this.nextHandler = nextHandler;}@Overridepublic void handleOrder(Order order) {System.out.println("Waiter takes order from " + order.getCustomerName());if (nextHandler != null) {nextHandler.handleOrder(order);}}
}// 厨师
public class Chef implements OrderHandler {private OrderHandler nextHandler;public Chef(OrderHandler nextHandler) {this.nextHandler = nextHandler;}@Overridepublic void handleOrder(Order order) {System.out.println("Chef prepares dish: " + order.getDishName());if (nextHandler != null) {nextHandler.handleOrder(order);}}
}// 收银员
public class Cashier implements OrderHandler {@Overridepublic void handleOrder(Order order) {System.out.println("Cashier processes payment for " + order.getDishName());}
}

装饰者模式：为订单添加额外信息

// 装饰者抽象类
public abstract class OrderDecorator implements OrderHandler {protected OrderHandler nextHandler;public OrderDecorator(OrderHandler nextHandler) {this.nextHandler = nextHandler;}@Overridepublic abstract void handleOrder(Order order);
}// 装饰者：添加打包信息
public class PackagingDecorator extends OrderDecorator {public PackagingDecorator(OrderHandler nextHandler) {super(nextHandler);}@Overridepublic void handleOrder(Order order) {System.out.println("Packaging decorator adds packaging for " + order.getDishName());if (nextHandler != null) {nextHandler.handleOrder(order);}}
}

客户端代码：

public class Client {public static void main(String[] args) {// 构建责任链：服务员 -> 厨师 -> 装饰者（打包） -> 收银员OrderHandler cashier = new Cashier();OrderHandler packagingDecorator = new PackagingDecorator(cashier);OrderHandler chef = new Chef(packagingDecorator);OrderHandler waiter = new Waiter(chef);// 创建订单Order order = new Order("John", "Pizza");// 提交订单给责任链waiter.handleOrder(order);}
}

在这个例子中，责任链模式帮助我们实现了订单处理的链式调用，而装饰者模式允许我们动态地为订单添加额外的信息（比如打包）。通过这样的设计，我们可以更容易地扩展系统、添加新的处理者或者装饰者，而不必修改现有的类。

Waiter 的构造函数中传递的 nextHandler 是 Chef，而 Chef 的构造函数中传递的是 PackagingDecorator。