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Composite Pattern
Composite Pattern
Composite Pattern

Composite Pattern

💡
컨테이너와 내용물을 같게 다루기

Intent

Composite  is a structural design pattern that lets you compose objects into tree structures and then work with these structures as if they were individual objects.

Implementation

notion image
 
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핵심 - Composite과 Leaf 모두 Component의 구현체임 - Composite은 Leaf의 Collection을 가짐

Applicablity

  • Tree-like 구조가 필요할때
 

Come Examples

 
package oodesign.design.structural.composite;

abstract public class Component {

    private String name;

    public Component(String name){
        this.name = name;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

package oodesign.design.structural.composite;

import java.util.ArrayList;
import java.util.List;

public class Directory extends Component{

    List<Component> components = new ArrayList<>();

    public Directory(String name) {
        super(name);
    }


    public boolean addComponent(Component component){
        return components.add(component);
    }

    public boolean removeComponent(Component component){
        return components.remove(component);
    }
}

package oodesign.design.structural.composite;

public class File extends Component {

    private Object data;

    public File(String name) {
        super(name);
    }

    public Object getData() {
        return data;
    }

    public void setData(Object data) {
        this.data = data;
    }
}

package oodesign.design.structural.composite;

public class Main {

    public static void main(String[] args) {
        Directory root = new Directory("root");
        Directory home = new Directory("home");
        Directory ndy = new Directory("ndy");
        Directory music = new Directory("music");
        Directory picture = new Directory("picture");
        Directory doc = new Directory("doc");
        Directory user = new Directory("user");

        File track1 = new File("track1");
        File track2 = new File("track2");
        File pic1 = new File("pic1");
        File doc1 = new File("doc1");
        File java = new File("java");

        root.addComponent(home);
            home.addComponent(ndy);
                ndy.addComponent(music);
                    music.addComponent(track1);
                    music.addComponent(track2);
                 ndy.addComponent(picture);
                    picture.addComponent(pic1);
                 ndy.addComponent(doc);
                    doc.addComponent(doc1);
        root.addComponent(user);
            user.addComponent(java);

bfs(root);
    }

    private static void bfs(Component component){
        System.out.println(component.getName());
        if(component instanceof Directory){
            ((Directory)component).components.forEach(Main::bfs);
        }
    }
}

root
home
ndy
music
track1
track2
picture
pic1
doc
doc1
user
java

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