Question

我的枚举代码如下：

public class CoffeeFactory {

    public static enum Type {
        LONG_BLACK(4.0),
        FLAT_WHITE(4.75),
        MOCHA(5.5);

        private double price;

        Type(double price) {
            this.price = price;
        }

        public double getPrice() {
            return price;
        }
    }

    public static enum Ingredient {
        ESPRESSO(0.5),
        MILK(1),
        CHOCOLATE(1.5);

        private double cost;

        Ingredient(double cost) {
            this.cost = cost;
        }

        public double getCost() {
            return cost;
        }
    }

    public static Coffee CreateCoffee(Type type){
        ArrayList<Ingredient> ingredients = new ArrayList<Ingredient>();


        switch (type) {
        case FLAT_WHITE:
            ingredients.add(Ingredient.MILK);
            Coffee c1 = new Coffee(ingredients, type.FLAT_WHITE);
            return c1; //new Coffee(ingredients, Type.FLAT_WHITE);

            break;
        case LONG_BLACK:
            ingredients.add(Ingredient.ESPRESSO);
            return new Coffee(ingredients, Type.LONG_BLACK);

            break;
        case MOCHA:
            ingredients.add(Ingredient.CHOCOLATE);
            return new Coffee(ingredients, Type.MOCHA);

            break;
        default:
            break;
        }
    }



}

这是我创建咖啡的代码：

import patt.Coffee.CoffeeFactory.Ingredient;

public class Coffee {
    Type type;
    double cost;
    ArrayList<Ingredient> ingredients;

    public Coffee(ArrayList<Ingredient> ingredients, Type type) {
        this.type = type;

        this.ingredients = ingredients;

    }


    public double getCost() {
        return cost;
    }

    public double getPrice() {
        return type.ordinal();

    }

    public String listIngredients() {

        return type.toString();
    }
}

我得到的错误就在行中：

咖啡c1 =新咖啡（成分，类型.FLAT_WHITE）;

构造函数Coffee（ArrayList，CoffeeFactory.Type）未定义。有人可以解释并告诉我我做错了什么，或者我是否误解了什么。

Answer 1

该行

Coffee c1 = new Coffee(ingredients, type.FLAT_WHITE);

应该以下：

Coffee c1 = new Coffee(ingredients, type);

Coffee c1 = new Coffee(ingredients, Type.FLAT_WHITE);

你可能想要第一个。变量type已包含对Type枚举实例FLAT_WHITE的引用。你知道这一点，因为你在switch的那个分支。

Answer 2

这没有错。

    public static Coffee CreateCoffee(Type type){
    ArrayList<Ingredient> ingredients = new ArrayList<Ingredient>();
    switch (type) {
        case FLAT_WHITE:
            ingredients.add(Ingredient.MILK);
            Coffee c1 = new Coffee(ingredients, Type.FLAT_WHITE);
            return c1; //new Coffee(ingredients, Type.FLAT_WHITE);
        case LONG_BLACK:
            ingredients.add(Ingredient.ESPRESSO);
            return new Coffee(ingredients, Type.LONG_BLACK);
        case MOCHA:
            ingredients.add(Ingredient.CHOCOLATE);
            return new Coffee(ingredients, Type.MOCHA);
        default:
            break;
    }
    return null;
}

未定义的构造函数枚举Java

2 个答案: