Java-单链表的实现

/**
 * establish a single linked list
 * 创建一个单链表
 * @author fred
 *
 */
public class SingleLinkedList<E> {
    private Node<E> head;
    private E data;
    private int size;

    //constructor
    public SingleLinkedList() {
        head = new Node();
    }
    
    //get the size of the list
    //得到该链表的大小
    public int getSize() {
        return size;
    }
    
    //insert data into the end of the list 
    //向链表顺序添加data
    public void add(E data) {
        Node<E> node = new Node(data, null);
        Node<E> temp = head;
        while(temp.next != null) {
            temp = temp.next;
        }
        temp.next = node;
        size++;
    }
    
    //insert data into the list at the special position
    //在链表中指定的位置index添加data
    public void insertByIndex(E data, int index) {
        if(index < 1 || index > size) {
            System.out.println("脚标越界");
            return;
        }
        Node<E> node = new Node(data, null);
        Node<E> temp = head;
        
        int count = 1;
        while(temp.next != null) {
            if(count++ == index) {
                node.next = temp.next;
                temp.next = node;
                size++;
                return;
            }
            else {
                temp = temp.next;
            }
        }
        
    }
    
    //delete the data at a sepcial position
    //删除链表中指定位置的数据
    public void deleteByIndex(int index) {
        Node<E> temp = head;
        int count = 1;
        while(temp.next != null) {
            if(count++ == index) {
                temp.next = temp.next.next;
                return;
            }
            else {
                temp = temp.next;
            }
        }
    }
    
    //clear the list
    //清空链表
    public void clear() {
        size = 0;
        head.next = null;
    }
    
    @Override
    public String toString() {
        String result = "data: ";
        Node<E> temp = head;
        while(temp.next != null) {
            temp = temp.next;
            result += temp.data + ", ";
        }
        return result;
    }

    //establish a inner Node class
    //叶子类
    private class Node<E>{
        private E data;
        private Node<E> next;
        
        public Node(){
            this.data = null;
            this.next = null;
        }
        
        public Node(E data, Node<E> next) {
            this.data = data;
            this.next = next;
        }
    }
    
}