public class LinkedQueue implements Serializable,QueueInterface {
	//佇列前端的節點
	private Node firstNode;
	//對列後端的節點
	private Node lastNode;
	//構造方法初始化
	public LinkedQueue(){
		firstNode=null;
		lastNode=null;
	}
	@Override
	public void enqueue(Object newEntity) {
		Node newNode=new Node(newEntity, null);
		if(isEmpty()){
			firstNode=newNode;
		}else{
			lastNode.setNextNode(newNode);
		}
	}

	@Override
	public Object dequeue() {
		Object front=null;
		if(!isEmpty()){
			front=firstNode.getData();
			firstNode=firstNode.getNextNode();
			
			if(firstNode==null)
				lastNode=null;
		}
	       return front;
	}

	@Override
	public Object getFront() {
		Object front =null;
		if(!isEmpty())
			front=firstNode.getData();
		return front;
	}

	@Override
	public boolean isEmpty() {
		return firstNode==null;
	}

}