Experiment Task: Composite Pattern

Implement the "Folder Browisng" Example Using Transparent Composite Patern

1. Class Diagram

(Class diagram omitted)

2. Source Code

public abstract class Node {
    private String label = "";

    public Node(String label) {
        this.label = label;
    }

    protected String getLabel() {
        return label;
    }

    protected abstract void display(String prefix);

    protected void add(Node node) {
        throw new UnsupportedOperationException("This object does not support add operation");
    }

    protected void remove(Node node) {
        throw new UnsupportedOperationException("This object does not support remove operation");
    }
}

public class LeafNode extends Node {
    public LeafNode(String label) {
        super(label);
    }

    @Override
    public void display(String prefix) {
        System.out.println(prefix + "-" + getLabel());
    }
}

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

public class CompositeNode extends Node {
    private List<Node> children = new ArrayList<>();

    public CompositeNode(String label) {
        super(label);
    }

    @Override
    protected void display(String prefix) {
        System.out.println(prefix + "+" + getLabel());
        if (children != null) {
            for (Node child : children) {
                child.display(prefix + " ");
            }
        }
    }

    @Override
    protected void add(Node node) {
        children.add(node);
    }

    @Override
    protected void remove(Node node) {
        children.remove(node);
    }
}

public class Client {
    public static void main(String[] args) {
        Node rootFolder = new CompositeNode("Clothing");

        Node summerClothes = new CompositeNode("Summer Wear");
        Node winterClothes = new CompositeNode("Winter Wear");

        LeafNode dress = new LeafNode("Dress");
        LeafNode vest = new LeafNode("Vest");
        LeafNode coat = new LeafNode("Coat");

        rootFolder.add(summerClothes);
        rootFolder.add(winterClothes);

        summerClothes.add(dress);
        summerClothes.add(vest);
        winterClothes.add(coat);

        rootFolder.display("");
    }
}

The output will show the folder structure with '+' for folders and '-' for leaf nodes, indented to representt hierarchy.