检测 Class 实现接口的对象

Question

我正在编写一个游戏，作为游戏的一部分，玩家应该能够点击各种 GUI 项目并查看 GUI 特定区域的更多详细信息。我正在通过一个由合适的游戏对象实现的接口 Detailable 进行管理，并将适当的信息发送到 JPanel

还有一些容器（全部实现 Detailable）包含其他（Detailable 实现）对象。目标是可以单击一个容器，并在其统计信息中查看其内容，然后依次单击以查看 它们的 统计信息等

我遇到的问题是编写容器的 addToContents(Detailable d) 方法。每个容器作为容器 "type" 的 ArrayList<String> - 衣橱、书柜等。我希望能够仅向给定容器添加某些 classes - 所以容器具有例如，"bookcase" 的类型将只接受 class Book 或 Curio 的对象。

我目前拥有的是：

public boolean addToContents(Detailable d){
        if(this.types.contains("bookcase") && d.getClass().getName().equals("Book")){
            //do some stuff
            //I know "Book" isn't the right syntax, this is just to demo
            return true;
        }
        else if(this.types.contains("bookcase") && d.getClass().getName().equals("Curio")){
            //other stuff
            return true;
        }
        //etc
        else{
             return false;
        }
    }

但这感觉像是错误的做法。有没有更好的办法？理想情况下，为了简单的代码，我会有类似 (pseudocode)

Constructor:
private ArrayList<Class> classesAccepted = <list of classes>

addToContents:
if (classesAccepted.contains(d.getClass()){
    add the thingie to contents
    return true
}
else{
     return false;
}

但我似乎无法找到一种方法来将 classes 的列表添加到构造函数 - 将 class 名称的 ArrayList 转换为对实际 class.

容器当前从 JSON 中读取，因此包含两个 classes:

public class FurnitureType {
    private String name;
    private List<String> type;
    private int cost;
    private String description;
    private int comfortBonus;
    private int capacity;
    //plus getters for all the above
}

public class Furniture implements Detailable, ListSelectionListener{

private String name;
private List<String> types;
private int cost;
private String description;
private int comfortBonus;
private int capacity;
private ArrayList<Detailable> contents;
private transient DetailPanel dp = null;

public Furniture (FurnitureType type){
    this.name=type.getName();
    this.types = type.getType();
    this.cost = type.getCost();
    this.description = type.getDescription();
    this.comfortBonus = type.getComfortBonus();
    this.capacity = type.getCapacity();
    this.contents = new ArrayList();
}
//appropriate getters

public boolean addToContents(Detailable d){
        if(this.types.contains("bookcase") && d.getClass().getName().equals("Book")){
            //do some stuff
            //I know "Book" isn't the right syntax, this is just to demo
            return true;
        }
        else if(this.types.contains("bookcase") && d.getClass().getName().equals("Curio")){
            //other stuff
            return true;
        }
        //etc
        else{
             return false;
        }
    }
@Override
public String toString(){
    return description;
}

@Override
public Icon getBigPic() {
    return null;
}

@Override
public JComponent getStats() {
    Object [] objectContents = contents.toArray();
    JList contentList = new JList(objectContents);
    contentList.setPreferredSize(new Dimension (400, 300));
    contentList.setFixedCellHeight(50);
    contentList.addListSelectionListener(this);
    contentList.setCellRenderer(new CustomCellRenderer());
    //the CustomCellRenderer class simply makes long descriptions into multiline cells
    return contentList;
}

@Override
public void addPanel(DetailPanel dp) {
    this.dp = dp;
}

@Override
public void valueChanged(ListSelectionEvent lse) {
    Detailable d = contents.get(lse.getFirstIndex());
    dp.updatePanel(d);
}

Answer 1

如果我没有正确理解你的问题，那么你正在寻找这样的东西

ArrayList <Class<? extends Detailable>> acceptedClasses = new ArrayList<>();

acceptedClasses.add(Bookcase.class);
acceptedClasses.add(OtherAcceptable.class);

然后做一些类似于

的事情

boolean test = 
    acceptedClasses.stream().anyMatch(clazz -> aClass.isInstance(detailableInstance));

检查实例是否为可接受的类型

Answer 2

您实际上可以使用 Map，如下所示：

private static Map<String, List<Class<? extends Detailable>>>
       bookcaseContainer = new HashMap<>();

 static {
       //load the bookcaseContainer Map from properties/database
         bookcaseContainer.put("bookcase", list1);
         bookcaseContainer.put("wardrobe", list2);
    }


if(bookcaseContainer.get("bookcase") != null && 
        bookcaseContainer.get("bookcase").contains(d.getClass())) {
        //do something here
 } else if(bookcaseContainer.get("wardrobe") != null && 
        bookcaseContainer.get("wardrobe").contains(d.getClass())) {
        //do something here
 }

检测 Class 实现接口的对象

Detecting Class of an object implementing an interface

java

class

implements