java - 使用LinkedList的迭代器打印值，在java中不断陷入无限循环

Question

所以我正在用java编写一个双向链表实现，我需要打印出值，以便我可以测试代码是否有效。然而，在过去的几天里，我一直在试图找出为什么我总是陷入无限循环。这是我的代码:

public class DoublyLinkedList<T> implements LinkedListInterface<T>, Iterable<T>{

private Node<T> head;
private Node<T> tail;
private int size;

//add, remove, clear, isempty methods, etc.

private class LinkedListIterator<E> implements java.util.Iterator<E> {

    private Node<E> probe;

    public LinkedListIterator(Node<T> head) {
        probe = (Node<E>)(head);
    }
    public boolean hasNext() {
        return (probe!= null);
    }

    public E next() {
        if (!hasNext()) {
            throw new NoSuchElementException("There is no element.");
        }
        E temp = probe.getData();
        probe = probe.getNext();
        return temp;
    }

    public void remove() {
        throw new UnsupportedOperationException("We don't support this function.");
    }

}

我尝试打印出这些值，但我只得到一个无限重复的值。这是怎么回事？非常感谢您的帮助。主要是，这就是我所拥有的:

    DoublyLinkedList<Integer> list = new DoublyLinkedList<Integer>();
    list.add(0, 1);
    list.add(1, 2);
    for (Integer i : list) {
        System.out.print(i + " ");
    }

这是节点类的代码:

public class Node<E> {

private E data;
private Node<E> next;
private Node<E> prev;

public Node(E data) {
    //do I need this?
    this.data = data;
}

@Override
public String toString() {
    //TODO
    return data + " ";
}
// Implement Methods
public E getData() {
    return data;
}
public Node<E> getNext() {
    return next;
}
public Node<E> getPrev() {
    return prev;
}

public void setData(E e) {
    data = e;
}
public void setNext(Node<E> e) {
    next = e;
}
public void setPrev(Node<E> e) {
    prev = e;
}

}

编辑:这是我的添加方法:

    public boolean add(int index, T data) {
    // TODO
    boolean toReturn = false;
    if (data == null) return false;
    if (index == 0) {
        Node<T> toAdd = new Node<T>(data);
        if (isEmpty()) {
            head = toAdd;
            tail = toAdd;
        } else {
            head.setPrev(toAdd);
        }
        toAdd.setNext(head);
        head = toAdd;
        toReturn = true;
    } else if (index == size()) {
        Node<T> toAdd = new Node<T>(data);
        if (isEmpty()) {
            head = toAdd;
            tail = toAdd;
        } else {
            tail.setNext(toAdd);
            toAdd.setPrev(tail);
        }
        tail = toAdd;
        toReturn = true;
    } else {
        Node<T> toAdd = new Node<T>(data);
        if (isEmpty()) {
            head = toAdd;
            tail = toAdd;
        } else {
            getNodeAt(index).setPrev(toAdd);
        }
        toAdd.setNext(getNodeAt(index));
        getNodeAt(index-1).setNext(toAdd);
        toReturn = true;
    }
    size++;
    return toReturn;
}

以下是我的 getNodeAt() 方法:

    private Node<T> getNodeAt(int index) {
    int count = 0;
    Node<T> element = head;
    while (element !=  null) {
        if (count == index) {
            return element;
        } else {
            count++;
            element = element.getNext();
        }
    }
    return null;
}

Answer 1

我愿意打赌您的问题出在节点中(您不提供代码)。检查 Node.getNext() 是否实际上返回下一个节点，而不是对其自身的引用。