存储布尔值

Question

我有一个问题，如何更改给定类的布尔值，以便一旦再次遇到它，它就具有上次设置的值。这是我的课

public class Sandwich {
    private String type;
    private double price;
    private String ing;
    public boolean owned;

    Sandwich (String t, double p, boolean o){
        type = t;
        price = p;
        owned = o;
    }

    public boolean getO(){
        return this.owned;
    }

    public void setO(boolean o){
        this.owned = o;
    }

    public String getType(){
        return this.type;
    }
}

以及访问和应该更改的位置：

public void purchase(Sandwich s) {
    boolean owned = s.owned;

    //I tried also with accessor and mutator here but then changed to public
    String type = s.getType();
    if (owned == false) {
        if (money <= 0){ 
            System.out.println("Worker " + this.name + " can not buy " + type + " sandwich, cuz he doesn't have enough money");
        } else {
            System.out.println("Worker " + this.name + " can buy " + type + " sandwich");
            this.money = money;
            owned = true;

            //this is the place where it is supposed to change value to true (sandwich was bought and has owner now
            s.owned = owned;
        }
    } else if (owned == true) {
        System.out.println("Worker " + this.name + " can not buy " + type + " sandwich cuz it was bought");
        System.out.println("Test");
    }
}

问题是，尽管过去购买了给定的三明治，但每次我尝试运行此代码时，它的拥有值都设置为 false。我需要三明治记录所拥有的更改值，以便下次我运行该条件时将拥有 == true。怎么可能

Answer 1

您的设计似乎存在缺陷。您需要在 Worker 和 Sandwish 类型之间建立关系。

您可以做的只是在工人类中实现一个已购买三明治类型的列表，并在工人购买三明治时与它进行比较。

或者，如果您愿意，您可以拥有一个包含所有 Sandwish 类型的哈希图，并带有一个布尔值，指示该类型是否已被购买。

Answer 2

您创建了 get 和 set 例程，然后没有使用它们。我会把代码改成这个。

    public void purchase(Sandwich s){
            String type = s.getType();
            if (!(s.getO())){
                if (money <= 0){ 
                    System.out.println("Worker " + this.name + " can not buy " + type + " sandwich, cuz he doesn't have eno

ugh money");
                } else {
                    System.out.println("Worker " + this.name + " can buy " + type + " sandwich");
                    this.money = money;
                    s.setO(true);
                }
            } else {
                System.out.println("Worker " + this.name + " can not buy " + type + " sandwich cuz it was bought");
                System.out.println("Test");
            }
     }

Answer 3

删除

boolean owned = s.owned;

在你使用过owned的地方使用s.getO()

例如

if (owned == false){ 

可以

if (!s.getO()){

并使用setter方法s.setO(true/false)进行更改。

例如

owned = true;
s.owned = owned;

可以替换为

s.setO(true);