构造泛型问题

Question

我正在制作一个基于文本的小游戏，只是为了好玩，我正在研究泛型，运行遇到了问题。

我有一个 class 可装备：

public class Equippable extends Item
{
    double mDurability; 

    public Equippable(String name, double weight, double durability)
    {
        super(name, weight);
        mDurability = durability;
    }//Equippable

    //Getters
    public double getDurability(){return mDurability;}

    //Setters
    public void setDurability(double Durability){mDurability = Durability;} 
}//Equippable

我有一个名为 BodyPart 的 class 的构造函数，我想接受 Equippable 的任何子 class 作为参数：

public BodyPart(String name,  Class<? extends Equippable> equipClass)
{
    mName         = name;
    mEquipClass   = equipClass;
}//BodyPart

可装备一件class装甲。

public class Armor extends Equippable
{
    double mArmorRating;

    public Armor(String name, double weight, double durability, double armorrating) 
    {
        super(name, weight, durability);
        mArmorRating = armorrating;
    }//Armor
}//Armor

最后我有几个 class 扩展 Armor.class。我不会 post 它们全部因为它们在这一点上是相同的，除了 class.

的名称

public class HumanoidBodyArmor extends Armor
{

    public HumanoidBodyArmor(String name, double weight, double durability, double armorrating) 
    {
        super(name, weight, durability, armorrating);
    }//HumanoidBodyArmor
}//HumanHeadArmor

当我这样做时：

BodyPart bp = new BodyPart("Head"  , Armor.class));

一切正常，对象已创建。但是当我这样做时

BodyPart bp = new BodyPart("Head"  , HumanHeadArmor.class));

Eclipse 发脾气说

The constructor BodyPart(String, Class<HumanoidHeadArmor>) is undefined

我非常确定这会起作用，但显然我遗漏了一些东西。有人可以阐明这个问题吗？

我这样做只是为了理智

Equippable.class.isAssignableFrom(HumanoidHeadArmor.class)

它确实评估为真。

编辑根据评论中的要求，这是 HumanoidBodyArmor class

public class HumanoidBodyArmor extends Armor
{

    public HumanoidBodyArmor(String name, double weight, double durability, double armorrating) 
    {
        super(name, weight, durability, armorrating);
    }//HumanoidBodyArmor
}//HumanoidBodyArmor

headarmor/bodyarmor/footarmor没有区别。除了名字之外，它们都是相同的。只是具有相同构造函数的空 classes，这些构造函数只是调用它们父级的 (Armor) 构造函数。

Answer 1

您没有正确使用 generics

首先，Equippable 可能应该是 interface 而不是 class，并且 Armor 也可以是扩展 interface Equippable

那你可以

public class BodyPart {

    public BodyPart(String name,  Equipable equip)
    {
        mName         = name;
        mEquip   = equip;
    }
}

and

public class Head extends BodyPart {
    public Head(String name, HumanoidHeadArmor equippable) {
      super(name, equippable);
    }
}

Answer 2

这一切对我来说都很好 - 我怀疑你有一些命名问题。

class Item {

    public Item(String name, double weight) {

    }
}

public class Equippable extends Item {

    double mDurability;

    public Equippable(String name, double weight, double durability) {
        super(name, weight);
        mDurability = durability;
    }

    //Getters
    public double getDurability() {
        return mDurability;
    }

    //Setters
    public void setDurability(double Durability) {
        mDurability = Durability;
    }
}

class BodyPart {

    String name;
    Class<? extends Equippable> equipClass;

    public BodyPart(String name, Class<? extends Equippable> equipClass) {
        this.name = name;
        this.equipClass = equipClass;
    }
}

public class Armor extends Equippable {

    double mArmorRating;

    public Armor(String name, double weight, double durability, double armorrating) {
        super(name, weight, durability);
        mArmorRating = armorrating;
    }
}

public class HumanoidBodyArmor extends Armor {

    public HumanoidBodyArmor(String name, double weight, double durability, double armorrating) {
        super(name, weight, durability, armorrating);
    }
}

public void test() {
    BodyPart head = new BodyPart("Head", Armor.class);
    BodyPart body = new BodyPart("Body", HumanoidBodyArmor.class);
}

构造泛型问题

Constructor generics issue

java

eclipse

generics