java - 我将如何使用 if 语句来更改属性的值？

Question

我希望能够根据某些要求给出特定的折扣值，例如以下年龄:> 25 岁和专业 = 教师/教授获得 10% 的折扣，年龄 < 25 和 gradepoint > 7 获得 25% 的折扣

到目前为止，这是我使用双 OO 范式的代码:

public class customer {

    //attribute definitions
    private String name;
    private String address;
    private String profession;
    private Integer age;
    private Integer gradepoint;
    private double discount;

    //constructor
    public customer(String newName, String newAddress, String newProfession, Integer newAge, Integer newGradepoint, double newDiscount)
    {
        setName(newName);
        setAddress(newAddress);
        setProfession(newProfession);
        setAge(newAge);
        setGradepoint(newGradepoint);
        setDiscount (newDiscount);
    }

    //getters
    public String getName()
    { return name;}
    public String getAddress()
    { return address;}
    public String getProfession()
    { return profession;}
    public Integer getAge()
    { return age;}
    public Integer getGradepoint()
    { return gradepoint;}
    public double getDiscount()
    { return discount;}

    //setters
    public void setName (String newName)
    { name = newName;}
    public void setAddress (String newAddress)
    { address = newAddress;}
    public void setProfession (String newProfession)
    { profession = newProfession;}
    public void setAge (Integer newAge)
    { age = newAge;}
    public void setGradepoint (Integer newGradepoint)
    { gradepoint = newGradepoint;}
    public void setDiscount (double newDiscount)
    { discount = newDiscount;}

    //methods


}

我是否需要创建一个名为折扣或每种类型的折扣的子类？或者我可以直接在这个客户类中写一个方法来控制折扣？

Answer 1

write a method directly into this customer class to control the discount?

这个。使其成为计算字段。杀死 setDiscount 函数，杀死 discount 变量，并将 getDiscount 函数变成类似这样的东西:

public double getDiscount() {
    if (...) return ...;
    if (....) return ...;
    ...
}

...除非你想把它作为默认折扣，并且仍然允许修改，在这种情况下，将 discount 保留为一个属性，并将整个逻辑移动到构造函数中，有条件 setDiscount() 调用。