一份基于链表的队列API实现【Java】_doncoder的博客_java链表api

import java.util.*;
public class QueueOfMine<Item> implements Iterable<Item> {
	private int N;
	private Node first; //始终指向首节点
	private Node last; //始终指向尾节点
	private class Node{
		Item data;
		Node next;
	}
	public int getNum() {
		return N;
	}
	public boolean isEmpty() {
		return first == null ? true : false;
	}
	public Item dequeue() { 
		Item ans = first.data;
		first = first.next;
		if(isEmpty())
			last = null;
		N--;
		return ans;
	}
	public void enqueue(Item item) {
		Node oldLast = last;
		last = new Node();
		last.data = item;
		if(isEmpty())
			oldLast = last;
		else
			oldLast.next = last;
		N++;
	}
	public Iterator<Item> iterator(){
		return new QueueIterator();
	}
	private class QueueIterator implements Iterator<Item> {
		Node current = first;
		public boolean hasNext() {
			if(current != null)
				return true;
			else
				return false;
		}
		public Item next() {
			Item ans = current.data;
			current = current.next;
			return ans;
		}
		public void remove() {}
	}

}
import java.util.*;
public class QueueOfMine<It