我的项目应该实现两个类。基本链接列表和排序链接列表。一切似乎工作得很好，除了某些原因我不能遍历排序的链表。类结构如下：
public class BasicLinkedList<T> implements Iterable<T> {
public int size;
private class Node {
private T data;
private Node next;
private Node(T data) {
this.data = data;
next = null;
}
}
private Node head;
private Node tail;
public BasicLinkedList() {
head = tail = null;
}
//Add, remove method
public Iterator<T> iterator() {
return new Iterator<T>() {
Node current = head;
@Override
public boolean hasNext() {
return current != null;
}
@Override
public T next() {
if(hasNext()){
T data = current.data;
current = current.next;
return data;
}
return null;
}
@Override
public void remove(){
throw new UnsupportedOperationException("Remove not implemented.");
}
};
现在，当我测试这个课程时，它的工作正常。迭代器工作，我可以测试它。问题出现在排序链表列表中，它扩展了这个。这是它的实现和我在构造函数中使用的比较器类：
public class SortedLinkedList<T> extends BasicLinkedList<T>{
private class Node{
private T data;
private Node next;
private Node(T data){
this.data = data;
next = null;
}
}
private Node head;
private Node tail;
private Comparator<T> comp;
public SortedLinkedList(Comparator<T> comparator){
super();
this.comp = comparator;
}
这是比较器类和我在另一个类中运行的测试：
public class intComparator implements Comparator<Integer>{
@Override
public int compare(Integer o1, Integer o2) {
return o1 - o2;
}
}
public static void main(String[] args) {
System.out.println("---------------SortedLinkedList--------------");
SortedLinkedList<Integer> sortedList = new SortedLinkedList<Integer>(new intComparator());
sortedList.add(3);
sortedList.add(5);
sortedList.add(2);
for(int i: sortedList){
System.out.println(i);
}
}
没有打印出来。我假设继承的迭代器将帮助我遍历这个没有问题，并且显然它是合法的，因为for-each循环编译。只是没有打印出来的东西。我调试了它，所有添加，删除的东西按预期工作。只是迭代器没有做它应该做的事情。我应该为这个类创建一个单独的新迭代器吗？但是，由于我已经继承了冗余代码，这不是冗余代码吗？帮助赞赏！
编辑：这是排序列表的添加方法
public SortedLinkedList<T> add(T element){
Node n = new Node(element);
Node prev = null, curr = head;
if(head == null){
head = n;
tail = n;
}
//See if the element goes at the very front
else if(comp.compare(n.data, curr.data) <= 0){
n.next = head;
head = n;
}
//See if the element is to be inserted at the very end
else if(comp.compare(n.data, tail.data)>=0){
tail.next = n;
tail = n;
}
//If element is to be inserted in the middle
else{
while(comp.compare(n.data, curr.data) > 0){
prev = curr;
curr = curr.next;
}
prev.next = n;
n.next = curr;
}
size++;
return this;
}
答案 0 :(得分：1)
1）SortedLinkedList扩展BasicLinkedList，但两者都有
private Node head;
private Node tail
2）同样适用于private class Node。您在SortedLinkedList和BasicLinkedList中声明了Node类。你应该做的是宣告一次，（可能在超类？）并在两个地方使用相同的类。如果这样做，那么两个类都应该可以访问构造函数和字段。因此，您必须更改访问修饰符（private就是您现在所拥有的。）
我将发布下面有效的代码，但我没有花时间在设计上。只需发布它就可以演示如何更改代码以使其正常工作。您必须决定使用哪些访问修饰符以及将类放在何处。
import java.util.Comparator;
import java.util.Iterator;
public class Test {
public static void main(String[] args) {
System.out.println("---------------SortedLinkedList--------------");
SortedLinkedList<Integer> sortedList = new SortedLinkedList<Integer>(new intComparator());
sortedList.add(3);
sortedList.add(5);
sortedList.add(2);
for (int i : sortedList) {
System.out.println(i);
}
}
}
class BasicLinkedList<T> implements Iterable<T> {
public int size;
class Node {
T data;
Node next;
Node(T data) {
this.data = data;
next = null;
}
}
protected Node head;
protected Node tail;
public BasicLinkedList() {
head = tail = null;
}
// Add, remove method
public Iterator<T> iterator() {
return new Iterator<T>() {
Node current = head;
@Override
public boolean hasNext() {
return current != null;
}
@Override
public T next() {
if (hasNext()) {
T data = current.data;
current = current.next;
return data;
}
return null;
}
@Override
public void remove() {
throw new UnsupportedOperationException("Remove not implemented.");
}
};
}
}
class SortedLinkedList<T> extends BasicLinkedList<T> {
private Comparator<T> comp;
public SortedLinkedList(Comparator<T> comparator) {
super();
this.comp = comparator;
}
public SortedLinkedList<T> add(T element) {
Node n = new Node(element);
Node prev = null, curr = head;
if (head == null) {
head = n;
tail = n;
}
// See if the element goes at the very front
else if (comp.compare(n.data, curr.data) <= 0) {
n.next = head;
head = n;
}
// See if the element is to be inserted at the very end
else if (comp.compare(n.data, tail.data) >= 0) {
tail.next = n;
tail = n;
}
// If element is to be inserted in the middle
else {
while (comp.compare(n.data, curr.data) > 0) {
prev = curr;
curr = curr.next;
}
prev.next = n;
n.next = curr;
}
size++;
return this;
}
}
class intComparator implements Comparator<Integer> {
@Override
public int compare(Integer o1, Integer o2) {
return o1 - o2;
}
}