Decorator - electrical business promotions prices

1, case

1, the price of basic commodities
2, you can use two kinds of coupons and red envelopes promotions
3, based on the style mode, realized price calculation and expansion.

2, implementation code - the business logic

2.1, commodity

import java.math.BigDecimal;
import java.util.Map;

/**
 * 商品实体类
 */
public class Merchandise {
    private String sku;
    private String name;
    private BigDecimal price;
    private Map<PromotionType, SupportPromotions> supportPromotions;

    public String getSku() {
        return sku;
    }

    public void setSku(String sku) {
        this.sku = sku;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public BigDecimal getPrice() {
        return price;
    }

    public void setPrice(BigDecimal price) {
        this.price = price;
    }

    public Map<PromotionType, SupportPromotions> getSupportPromotions() {
        return supportPromotions;
    }

    public void setSupportPromotions(Map<PromotionType, SupportPromotions> supportPromotions) {
        this.supportPromotions = supportPromotions;
    }
}

2.2, order class

import java.math.BigDecimal;
import java.util.List;

/**
 * 订单实体类
 */
public class Order {
    private int id;
    private String orderNo;
    private BigDecimal totalPayMoney;
    private List<OrderDetail> list;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getOrderNo() {
        return orderNo;
    }

    public void setOrderNo(String orderNo) {
        this.orderNo = orderNo;
    }

    public BigDecimal getTotalPayMoney() {
        return totalPayMoney;
    }

    public void setTotalPayMoney(BigDecimal totalPayMoney) {
        this.totalPayMoney = totalPayMoney;
    }

    public List<OrderDetail> getList() {
        return list;
    }

    public void setList(List<OrderDetail> list) {
        this.list = list;
    }
}

2.3 Class Order Details

import java.math.BigDecimal;

/**
 * 订单明细类
 */
public class OrderDetail {
    private int id;
    private int orderId;
    private Merchandise merchandise;
    private BigDecimal payMoney;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public int getOrderId() {
        return orderId;
    }

    public void setOrderId(int orderId) {
        this.orderId = orderId;
    }

    public Merchandise getMerchandise() {
        return merchandise;
    }

    public void setMerchandise(Merchandise merchandise) {
        this.merchandise = merchandise;
    }

    public BigDecimal getPayMoney() {
        return payMoney;
    }

    public void setPayMoney(BigDecimal payMoney) {
        this.payMoney = payMoney;
    }
}

2.4 Types promotions

/**
 * 优惠活动枚举
 */
public enum PromotionType {
    COUPON(1),
    REDPACKET(2),
    ;
    private int code;

    PromotionType(final int code){
        this.code = code;
    }

    public int getCode() {
        return code;
    }

    public void setCode(int code) {
        this.code = code;
    }
}

2.5 Coupons class

import java.math.BigDecimal;

/**
 * 用户优惠券类
 */
public class UserCoupon {
    private int id;
    private int userId;
    private String sku;
    private BigDecimal coupon;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public int getUserId() {
        return userId;
    }

    public void setUserId(int userId) {
        this.userId = userId;
    }

    public String getSku() {
        return sku;
    }

    public void setSku(String sku) {
        this.sku = sku;
    }

    public BigDecimal getCoupon() {
        return coupon;
    }

    public void setCoupon(BigDecimal coupon) {
        this.coupon = coupon;
    }
}

2.6 class red envelopes

import java.math.BigDecimal;

/**
 * 用户红包类
 */
public class UserRedPacket {
    private int id;
    private int userId;
    private String sku;
    private BigDecimal redPacket;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public int getUserId() {
        return userId;
    }

    public void setUserId(int userId) {
        this.userId = userId;
    }

    public String getSku() {
        return sku;
    }

    public void setSku(String sku) {
        this.sku = sku;
    }

    public BigDecimal getRedPacket() {
        return redPacket;
    }

    public void setRedPacket(BigDecimal redPacket) {
        this.redPacket = redPacket;
    }
}

2.7, the type of product support promotions

/**
 * 商品支持的优惠活动，依次计算价格
 */
public class SupportPromotions implements Cloneable {
    private int id;
    private PromotionType promotionType;
    private int priority;
    private UserCoupon userCoupon;
    private UserRedPacket userRedPacket;

    public SupportPromotions clone(){
        SupportPromotions supportPromotions = null;
        try {
            supportPromotions = (SupportPromotions) super.clone();
        } catch (CloneNotSupportedException e) {
            e.printStackTrace();
        }

        return supportPromotions;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public PromotionType getPromotionType() {
        return promotionType;
    }

    public void setPromotionType(PromotionType promotionType) {
        this.promotionType = promotionType;
    }

    public int getPriority() {
        return priority;
    }

    public void setPriority(int priority) {
        this.priority = priority;
    }

    public UserCoupon getUserCoupon() {
        return userCoupon;
    }

    public void setUserCoupon(UserCoupon userCoupon) {
        this.userCoupon = userCoupon;
    }

    public UserRedPacket getUserRedPacket() {
        return userRedPacket;
    }

    public void setUserRedPacket(UserRedPacket userRedPacket) {
        this.userRedPacket = userRedPacket;
    }
}

3, implementation code - decorator

3.1 Basic interface class

import java.math.BigDecimal;

/**
 * 基本接口类
 */
public interface IBaseCount {
    /**
     * 计算订单商品支付金额
     */
    BigDecimal countPayMoney(OrderDetail orderDetail);
}

3.2, the basic implementation class

import java.math.BigDecimal;

/**
 * 基本实现类
 */
public class BaseCount implements IBaseCount {
    @Override
    public BigDecimal countPayMoney(OrderDetail orderDetail) {
        orderDetail.setPayMoney(orderDetail.getMerchandise().getPrice());
        System.out.println("商品原单价金额为：" + orderDetail.getPayMoney());

        return orderDetail.getPayMoney();
    }
}

3.3, decorator - abstract base class

import java.math.BigDecimal;

/**
 * 装饰器-基本抽象类
 */
public abstract class BaseCountDecorator implements IBaseCount {
    private IBaseCount count;

    public BaseCountDecorator(IBaseCount count) {
        this.count = count;
    }

    public BigDecimal countPayMoney(OrderDetail orderDetail) {
        BigDecimal payTotalMoney = new BigDecimal(0);
        if(count != null) {
            payTotalMoney = count.countPayMoney(orderDetail);
        }

        return payTotalMoney;
    }
}

3.4, decorator - Coupons class

import java.math.BigDecimal;

/**
 * 装饰器-优惠券实现类
 */
public class CouponDecorator extends BaseCountDecorator {

    public CouponDecorator(IBaseCount count) {
        super(count);
    }

    public BigDecimal countPayMoney(OrderDetail orderDetail){
        BigDecimal payTotalMoney = new BigDecimal(0);

        payTotalMoney = super.countPayMoney(orderDetail);
        payTotalMoney = countCouponPayMoney(orderDetail);

        return payTotalMoney;
    }

    private BigDecimal countCouponPayMoney(OrderDetail orderDetail) {
        BigDecimal coupon = orderDetail.getMerchandise().getSupportPromotions().get(PromotionType.COUPON).getUserCoupon().getCoupon();
        System.out.println("优惠券金额：" + coupon);
        orderDetail.setPayMoney(orderDetail.getPayMoney().subtract(coupon));

        return orderDetail.getPayMoney();
    }
}

3.4, decorator - red class

import java.math.BigDecimal;

/**
 * 装饰器-优惠券实现类
 */
public class RedPacketDecorator extends BaseCountDecorator {

    public RedPacketDecorator(IBaseCount count) {
        super(count);
    }

    public BigDecimal countPayMoney(OrderDetail orderDetail){
        BigDecimal payTotalMoney = new BigDecimal(0);

        payTotalMoney = super.countPayMoney(orderDetail);
        payTotalMoney = countCouponPayMoney(orderDetail);

        return payTotalMoney;
    }

    private BigDecimal countCouponPayMoney(OrderDetail orderDetail) {
        BigDecimal redPacket = orderDetail.getMerchandise().getSupportPromotions().get(PromotionType.REDPACKET).getUserRedPacket().getRedPacket();
        System.out.println("红包优惠金额：" + redPacket);
        orderDetail.setPayMoney(orderDetail.getPayMoney().subtract(redPacket));

        return orderDetail.getPayMoney();
    }
}

3.5, promotions factory class computing

import java.math.BigDecimal;
import java.util.Map;

/**
 * 优惠活动价格计算工具类
 */
public class PromotionFactory {
    public static BigDecimal getPayMoney(OrderDetail orderDetail) {
        Map<PromotionType, SupportPromotions> supportPromotionslist = orderDetail.getMerchandise().getSupportPromotions();

        IBaseCount baseCount = new BaseCount();

        if(supportPromotionslist != null) {
            for(PromotionType type : supportPromotionslist.keySet()) {
                baseCount = protmotion(supportPromotionslist.get(type), baseCount);
            }
        }

        return baseCount.countPayMoney(orderDetail);
    }

    private static IBaseCount protmotion(SupportPromotions supportPromotions, IBaseCount baseCount){
        if(supportPromotions.getPromotionType() == PromotionType.COUPON) {
            baseCount = new CouponDecorator(baseCount);
        }
        if(supportPromotions.getPromotionType() == PromotionType.COUPON) {
            baseCount = new RedPacketDecorator(baseCount);
        }

        return baseCount;
    }
}

result: