JAVA单向链表的实现

package com.leo_faith.www;

 public class Node {
    Object data;

    Node next;

    Node(Object d) {
        data = d;
         next = null;
    }
}

package com.leo_faith.www;

public class Node {
	Object data;

	Node next;

	Node(Object d) {
		data = d;
		next = null;
	}
}

 

package com.leo_faith.www;

 public class LinkList {

     /* 用变量来实现表头 */
     private Node Head = null;

     private Node Tail = null;

     private Node Pointer = null; //point to previous

     private int Length = 0;

     public void deleteAll() {// 清空整个链表
         Head = null;
         Tail = null;
         Pointer = null;
         Length = 0;
    }

     // 链表复位，使第一个节点成为当前节点
     public void reset() {
         Pointer = null;
    }

     // 判断链表是否为空
     public boolean isEmpty() {
         return (Length == 0);
    }

     // 判断当前结点是否为最后一个结点
     public boolean isEnd() {
         if (Length == 0)
             throw new java.lang.NullPointerException();
         else if (Length == 1)
             return true;
         else
             return (cursor() == Tail);
    }

     // 返回当前结点的下一个结点的值，并使其成为当前结点
     public Object nextNode() {
         if (Length == 1)
             throw new java.util.NoSuchElementException();
         else if (Length == 0)
             throw new java.lang.NullPointerException();
         else {
            Node temp = cursor();
            Pointer = temp;
             if (temp != Tail)
                 return (temp.next.data);
             else
                 throw new java.util.NoSuchElementException();
        }
    }

     // 返回当前结点的值
     public Object currentNode() {
        Node temp = cursor();
         return temp.data;
    }

     // 在当前结点前插入一个结点，并使其成为当前结点
     public void insert(Object obj) {
         Node e = new Node(obj);
         if (Length == 0) {
            Tail = e;
            Head = e;
         } else {
            Node temp = cursor();
            e.next = temp;
             if (Pointer == null)
                Head = e;
             else
                Pointer.next = e;
        }
        Length++;
    }

     // 返回链表的大小
     public int size() {
         return Length;
    }

     // 将当前结点移出链表，下一个结点成为当前结点，
     // 如果移出的结点是最后一个结点，
     // 则第一个结点成为当前结点
     public Object remove() {
        Object temp;
         if (Length == 0)
             throw new java.util.NoSuchElementException();
         else if (Length == 1) {
            temp = Head.data;
            deleteAll();
         } else {
            Node cur = cursor();
            temp = cur.data;
             if (cur == Head)
                Head = cur.next;
             else if (cur == Tail) {
                 Pointer.next = null;
                reset();
             } else
                Pointer.next = cur.next;
            Length--;
        }
         return temp;
    }

     // 返回当前结点的指针
     private Node cursor() {
         if (Head == null)
             throw new java.lang.NullPointerException();
         else if (Pointer == null)
             return Head;
         else
             return Pointer.next;
    }

     // 链表的简单应用举例
     public static void main(String[] args) {
         LinkList a = new LinkList();
         for (int i = 1; i <= 10; i++)
             a.insert(new Integer(i));
         System.out.println("The currentNode is:" + a.currentNode());
         while (!a.isEnd())
             System.out.println("The nextNode is:" + a.nextNode());
        a.reset();
         while (!a.isEnd()) {
            a.remove();
        }
        a.remove();
        a.reset();
         if (a.isEmpty()) {
             System.out.println("There is no Node in List");
        }
    }
}