使用链表Java的队列ADT

public class LinkedListQueue<T> {
    private Node<T> head;
    private Node<T> tail;
    
    private class Node<T> {
        private T data;
        private Node<T> next;
        
        public Node(T data) {
            this.data = data;
            this.next = null;
        }
    }
    
    public LinkedListQueue() {
        this.head = null;
        this.tail = null;
    }
    
    public boolean isEmpty() {
        return head == null;
    }
    
    public void enqueue(T data) {
        Node<T> newNode = new Node<>(data);
        
        if (isEmpty()) {
            head = newNode;
            tail = newNode;
        } else {
            tail.next = newNode;
            tail = newNode;
        }
    }
    
    public T dequeue() {
        if (isEmpty()) {
            throw new NoSuchElementException("Queue is empty");
        }
        
        T data = head.data;
        head = head.next;
        
        if (head == null) {
            tail = null;
        }
        
        return data;
    }
    
    public T peek() {
        if (isEmpty()) {
            throw new NoSuchElementException("Queue is empty");
        }
        
        return head.data;
    }
}