我一直收到错误"Node<E> is not generic; it cannot be parametized with arguments E"和"front cannot be re

Question

我正在用Java制作一个队列的链接实现。问题是，当我把它和其他需要的.java文件（Queue、QueueDriver等）放在一个包中（我使用的是默认包）时，它只显示错误。它在包外运行良好。我正在使用Eclipse。

    public class LinkedQueue<E> implements Queue<E>{
/**
 * Initialize the pointers
 */
private Node<E> front;
private Node<E> rear;
/**
 * Initialize size of list
 */
private int size;
/**
 * Initialize the linked queue
 */
public LinkedQueue() {
    front = null;
    rear = null;
    size = 0;
}
/* (non-Javadoc)
 * @see Queue#isEmpty()
 */
@Override
public boolean isEmpty() {      
    return (front == null);
}
/* (non-Javadoc)
 * @see Queue#dequeue()
 */
@Override
public E dequeue() throws QueueEmptyException {
    if (isEmpty())
        throw new QueueEmptyException("Queue is empty!");
    else{
        E temp = (E) front.getElement();
        front = front.getNext();
        size--;
        return temp;
    }
}
/* (non-Javadoc)
 * @see Queue#enqueue()
 */
@Override
public void enqueue(E element) {
    Node<E> x = new Node<E>(element);
    if(front == null){
        front = rear = x;
    }
    else{
        rear.setNext(x);
        rear = x;
    }
    size++;
}
/* (non-Javadoc)
 * @see Queue#size()
 */
@Override
public int size() {     
    return size;
}
/* (non-Javadoc)
 * @see Queue#front()
 */
@Override
public E front() throws QueueEmptyException {
    if (isEmpty())
        throw new QueueEmptyException("Queue is empty!");
    return (E) front.getElement();
}

}

Answer 1

消息告诉您Node不是通用的。它需要像一样

public class Node<E> {
    // your code here, using E as the data in the node
}