java - 需要另一种方法来跟踪重量而不使用实例变量

Question

我正在尝试找出另一种方法来跟踪手提箱的当前重量，目前我使用实例变量，但我只允许使用 2，它是手提箱中的元素列表，最大重量。

有什么方法可以做到这一点？我尝试过创建另一种方法，但我只是想不出一种不使用实例变量的方法。

我的 Suitcase.java 代码:

ArrayList<Thing> things; // List stores name of object and weight of object
private int weight; // Need to get rid of this
private int maxWeight;

public Suitcase(int weight) {
    this.maxWeight = weight;
    this.weight = 0; // and this?
    this.things = new ArrayList<Thing>();
}

public void addThing(Thing thing) { // Need to modify this as well
    if (weight < this.maxWeight) {
        things.add(thing);
        weight += thing.getWeight();
        if (weight > this.maxWeight) {
            weight -= thing.getWeight();
            things.remove(things.size() - 1);
        }
    }
}

public Thing heaviestThing() {
    if (!things.isEmpty()) {
        for (int i = 0; i < things.size(); i++) {

        }
    }
    return null;
}

public void printThings() {
    for (Thing thing : things) {
        System.out.println(thing);
    }
}

public int totalWeight() {
    return this.maxWeight;
}

@Override
public String toString() { // This is where I have problems because I need to keep track of current weight.
    if (things.isEmpty()) {
        return "empty (" + weight + " kg)";
    } else if (things.size() == 1) {
        return things.size() + " thing (" + weight + " kg)";
    } else {
        return things.size() + " things (" + weight + " kg)";
    }
}

我的 Thing.java 代码

private String name;
private int weight;

public Thing(String name, int weight) {
    this.name = name;
    this.weight = weight;
}

public String getName() {
    return this.name;
}

public int getWeight() {
    return this.weight;
}

@Override
public String toString() {
    return this.name + " (" + weight + " kg)";
}

Answer 1

为什么不创建一个方法 calculateWeight() 而不是 int maxWeight:

public int calculateWeight() {
    int weight = 0;
    for (Thing thing : things) {
        weight += thing.getWeight();
    }
    return weight;
}