java - 具有 1 个类和 2 个子类但不使用继承的设计模式

Question

我需要实现一个具有2个子类的类，主类包含变量id，主类将变量发送到2个子类，在第一个子类中它可以更改变量的值，并且mainClass需要知道。第二个子类在第一个子类更改的数据库中查找值id。我无法使用继承，因为稍后我将使用其他第二个主类，并且我将需要使用两个子类。

我需要使用一种我不知道的设计模式。

这是我的代码示例。

//Main app
public class App {
    public static void main(String[] args) {
        MainPanel panel = MainPanel(20);
    }
}

//Main panel
public class MainPanel {
    int id;

    public MainPanel(int id){
        this.id = id;
    }
}

//Subpanel Person
public class SubPanelPerson {
    int id;

    public SubPanelPerson() { }

    public void changeValue() {
        this.id = 30;
    }
}

//Subpanel member
public class SubPanelmember {
    int id;

    public SubPanelMember() {}

    public void findMember() {
        find(id);
    }
}

Answer 1

我认为这个解决方案，我现在只使用 1 个面板，但稍后我需要使用 2 个面板。我用 2 个面板和 2 个子面板编写解决方案。

 class PanelBooks {
    int id;
    SubPanelPerson subPanelPerson = new SubPanelPerson(this);
    SubPanelMember subPanelMember = new SubPanelMember(this);

    public void setId(int id) { this.id = id; }
}

class PanelVideos {
    int id;
    SubPanelPerson subPanelPerson = new SubPanelPerson(this);
    SubPanelMember subPanelMember = new SubPanelMember(this);

    public void setId(int id) { this.id = id; }
}

class SubPanelPerson {
    private PanelBooks panelBooks;
    private PanelVideos panelVideos;

    public SubPanelPerson(PanelBooks panelBooks) {
        this.panelBooks = panelBooks;
    }

    public SubPanelPerson(PanelVideos panelVideos) {
        this.panelVideos = panelVideos;
    }

    public void changeValueBooks(int id) { this.panelBooks.setId(id); }
    public void changeValueVideos(int id) { this.panelVideos.setId(id); }
}

class SubPanelMember {
    private PanelBooks panelBooks;
    private PanelVideos panelVideos;

    public SubPanelMember(PanelBooks panelBooks) {
        this.panelBooks = panelBooks;
    }
    public SubPanelMember(PanelVideos panelVideos) {
        this.panelVideos = panelVideos;
    }

    public void findMemberBooks() { System.out.println("Find ID: " + this.panelBooks.id); }
    public void findMemberVideos() { System.out.println("Find ID: " + this.panelVideos.id); }
}

public static void main(String args[]) {
    PanelBooks panelBooks = new PanelBooks();
    PanelVideos panelVideos = new PanelVideos();

}

这是一个好的选择还是可以改进？