责任链模式

Posted 2021-02-16 mabaoqing

/**
 * 处理价格折扣的抽象类
 */
public abstract class PriceHandler {
     // 直接后继，用于传递请求
     protected PriceHandler successor;
     public void setSuccessor(PriceHandler successor) {
          this.successor = successor;
     }
     // 处理折扣请求
     public abstract void processDicount(float discount);
}

public class Sales extends PriceHandler {
     @Override
     public void processDicount(float discount) {
          if(discount <= 0.1) {
               System.out.format("%s批准了折扣：%.2f%n", this.getClass().getName(), discount);
          } else {
               successor.processDicount(discount);
          }
     }
}

public class Manager extends PriceHandler{
     @Override
     public void processDicount(float discount) {
          if(discount <= 0.3) {
               System.out.format("%s批准了折扣：%.2f%n", this.getClass().getName(), discount);
          } else {
               successor.processDicount(discount);
          }
     }
}

public class Boss extends PriceHandler {
     @Override
     public void processDicount(float discount) {
          if(discount <= 0.5) {
               System.out.format("%s批准了折扣：%.2f%n", this.getClass().getName(), discount);
          } else {
               System.out.format("%s拒绝了折扣：%.2f%n", this.getClass().getName(), discount);
          }
     }
}

/**
 * 创建PriceHandler的工厂类
 */
public class PriceHandlerFactory {
     public static PriceHandler createHandler() {
          PriceHandler sale = new Sales();
          PriceHandler manager = new Manager();
          PriceHandler boss = new Boss();
          sale.setSuccessor(manager);
          manager.setSuccessor(boss);
          return sale;
     }
}

public class Customer {
     private PriceHandler priceHandler;
     public Customer(PriceHandler priceHandler) {
          this.priceHandler = priceHandler;
     }

     public void requestDiscount(float discount) {
          priceHandler.processDicount(discount);
     }

     public static void main(String[] args) {
          Customer c = new Customer(PriceHandlerFactory.createHandler());
          for(int i=1;i<=10;i++) {
               System.out.print(i + "：");
               c.requestDiscount(new Random().nextFloat());
          }
     }
}