Iliev's homework Mariyan17320

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

class Node<T> {
    private T data = null;

    private List<Node<T>> children = new ArrayList<>();

    private Node<T> parent = null;

    public Node(T data) {
        this.data = data;
    }
    public Node<T> addChild(Node<T> child) {
        child.setParent(this);
        this.children.add(child);
        return child;
    }
    public void addChildren(List<Node<T>> children) {
        children.forEach(each -> each.setParent(this));
        this.children.addAll(children);
    }
    public List<Node<T>> getChildren() {
        return children;
    }
    public T getData() {
        return data;
    }
    public void setData(T data) {
        this.data = data;
    }
    private void setParent(Node<T> parent) {
        this.parent = parent;
    }
    public Node<T> getParent() {
        return parent;
    }
}
class TreeExample {
    public static void main(String[] args) {
        Node<String> root = createTree();
        printTree(root, " ");
    }
    private static Node<String> createTree() {
        Node<String> root = new Node<>("Mariyan");
        Node<String> node1 = root.addChild(new Node<String>("Krasimir"));
        Node<String> node11 = node1.addChild(new Node<String>("Angel"));
        Node<String> node12 = node1.addChild(new Node<String>("Totka"));
        Node<String> node2 = root.addChild(new Node<String>("Trayana"));
        Node<String> node21 = node2.addChild(new Node<String>("Hristo"));
        Node<String> node211 = node2.addChild(new Node<String>("Mariika"));
        return root;
    }
    private static <T> void printTree(Node<T> node, String appender) {
        System.out.println(appender + node.getData());
        node.getChildren().forEach(each -> printTree(each, appender + appender));
    }
}

//Mariyan17320