java - 应该如何修改这个类才能遵循 DIP(依赖注入(inject)原则)？

Question

如何修改此类以遵循 DIP(依赖倒置原则)，以便删除构造函数中的两个 ArrayList 依赖项？接口(interface)应该如何？

令我困惑的一件事是新引用指向 ArrayList<type>不仅仅是类的构造函数。我不知道如何处理这种情况......

package mvc.controllers;

import java.util.ArrayList;
import mvc.models.AbstractModel;
import mvc.views.AbstractViewPanel;

public abstract class AbstractController {

    private ArrayList<AbstractViewPanel> registeredViews;
    private ArrayList<AbstractModel> registeredModels;

    public AbstractController() {
        registeredViews = new ArrayList<AbstractViewPanel>();
        registeredModels = new ArrayList<AbstractModel>();
    }

    public void addModel(AbstractModel model) {
        registeredModels.add(model);
        model.addPropertyChangeListener(this);
    }

    public void removeModel(AbstractModel model) {
        registeredModels.remove(model);
        model.removePropertyChangeListener(this);
    }

    public void addView(AbstractViewPanel view) {
        registeredViews.add(view);
    }

    public void removeView(AbstractViewPanel view) {
        registeredViews.remove(view);
    }
    ...
}

Answer 1

要以依赖倒置方式执行此操作，您可以执行以下操作之一:

1. 列表的依赖关系在构造函数中给出:

   public abstract class AbstractController {
   
   private List<AbstractViewPanel> registeredViews;
   private List<AbstractModel> registeredModels;
   
   public AbstractController(List<AbstractViewPanel> registeredViews, List<AbstractModel> registeredModels) {
       this.registeredViews = registeredViews;
       this.registeredModels = registeredModels;
   }
   

2. 为列表添加修改器(setter):

   public abstract class AbstractController {
   
   private List<AbstractViewPanel> registeredViews;
   private List<AbstractModel> registeredModels;
   
   public AbstractController() {
   }
   
   public void setRegisteredViews(List<AbstractViewPanel> views) {
      this.registeredViews = views;
   }
   
   public void setRegisteredModels(List<AbstractModel> models) {
      this.registeredModels = models;
   }
   

顺便说一句，我将 ArrayList 更改为 List。无需引入对 List 实现的依赖。