带索引参数的链表java迭代器

Question

hi LinkedList的普通迭代器如下所示，但是，我们如何构建一个迭代器来返回从指定索引开始的迭代器？我们如何建立：

public Iterator<E>iterator(int index)???  

谢谢！ 普通迭代器：

    public Iterator<E> iterator( )
    {
        return new ListIterator();
    }

private class ListIterator implements Iterator<E>
    {
        private Node current;

        public ListIterator()
        {
            current = head; // head in the enclosing list
        }
        public boolean hasNext()
        {
            return current != null;
        }
        public E next()
        {
            E ret = current.item;
            current = current.next;
            return ret;
        }
        public void remove() { /* omitted because optional */ }
    }

Answer 1

你可以直接调用普通的iterator()方法，然后多次调用next()：

public Iterator<E> iterator(int index) {
    Iterator<E> iterator = iterator();
    for (int i = 0; i < index && iterator.hasNext(); i++) {
        iterator.next();
    }
    return iterator;
}

Answer 2

这是如何实现这种iterator的开始示例，但也建议创建或扩展适当的interface，并使此对象实现此interface作为约定

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

public class IterableObject {

    private List<String> values = new ArrayList<String>();


    public Iterator<String> getIterator(final int index) {

        Iterator<String> it = new Iterator<String>() {

            private int current = index;

            @Override
            public void remove() {
                // TODO Auto-generated method stub

            }

            @Override
            public String next() {
                String value = values.get(current);
                current++;
                return value;
            }

            @Override
            public boolean hasNext() {
                if(values.size() > current){
                    return true;
                }else{
                    return false;
                }

            }
        };

        return it;
    }

}

更新

根据评论，我为LinkedList写了一个迭代器

public Iterator<String> getIterator(final int index) {


        Iterator<String> it = new Iterator<String>() {

            private Object currentObject = null;

            {
                /*initialize block where we traverse linked list 
                  that it will pointed to object at place index*/
                System.out.println("initialize" + currentWord);
                for(int i = 0; currentObject.next != null && i < index; i++, currentObject = currentObject.next)
                    ;

            } 


            @Override
            public void remove() {
                // TODO Auto-generated method stub

            }

            @Override
            public String next() {
                Object obj = currentObject.next;
                currentObject = currentObject.next;
                return obj;
            }

            @Override
            public boolean hasNext() {
                return currentObject.next != null;

            }
        };

        return it;
    }

因为Iterator是Anonymous class的对象，所以我们不能使用constructor，但可以在初始化块中初始化它。看看这个答案：https://stackoverflow.com/a/362463/947111我们在开始时遍历它一次（很抱歉C风格），所以它将指向currentObject。所有代码都是自我解释的