import java.util.Iterator;
  
// Custom Linked List class using Generics
class List<T> implements Iterable<T> {
    Node<T> head, tail;
      
    // add new Element at tail of the linked list in O(1)
    public void add(T data)
    {
        Node<T> node = new Node<>(data, null);
        if (head == null)
            tail = head = node;
        else {
            tail.setNext(node);
            tail = node;
        }
    }
      
    // return Head
    public Node<T> getHead()
    {
        return head;
    }
      
    // return Tail
    public Node<T> getTail()
    {
        return tail;
    }
      
    // return Iterator instance
    public Iterator<T> iterator()
    {
        return new ListIterator<T>(this);
    }
}
  
class ListIterator<T> implements Iterator<T> {
    Node<T> current;
      
    // initialize pointer to head of the list for iteration
    public ListIterator(List<T> list)
    {
        current = list.getHead();
    }
      
    // returns false if next element does not exist
    public boolean hasNext()
    {
        return current != null;
    }
      
    // return current data and update pointer
    public T next()
    {
        T data = current.getData();
        current = current.getNext();
        return data;
    }
      
    // implement if needed
    public void remove()
    {
        throw new UnsupportedOperationException();
    }
}
  
// Constituent Node of Linked List
class Node<T> {
    T data;
    Node<T> next;
    public Node(T data, Node<T> next)
    {
        this.data = data;
        this.next = next;
    }
      
    // Setter getter methods for Data and Next Pointer
    public void setData(T data)
    {
        this.data = data;
    }
      
    public void setNext(Node<T> next)
    {
        this.next = next;
    }
      
    public T getData()
    {
        return data;
    }
      
    public Node<T> getNext()
    {
        return next;
    }
}
  
// Driver class
class Main {
    public static void main(String[] args)
    {
        // Create Linked List
        List<String> myList = new List<>();
          
        // Add Elements
        myList.add("abc");
        myList.add("mno");
        myList.add("pqr");
        myList.add("xyz");
          
        // Iterate through the list using For Each Loop
        for (String string : myList)
            System.out.println(string);
    }
}