【Java】LinkedList 底层原理，自己实现LinkedList

[code]package test;

/**
* 节点的类定义
* @author 袁盛桐
* @version 1.0
*/
class Node{
Node previous;
Object obj;
Node next;

}

/**
* 自己实现一个linkedlist，学习原理和底层实现
* @author 袁盛桐
* @version 1.0
*/
public class MyLinkedList {
private Node first;
private Node last;
private int size;

public int size() {
return size;
}

/**
* 检查输入的index是否在范围内
*/
public void rangeCheck(int index){
if(index<0||index>=size){
try {
throw new Exception();
} catch (Exception e) {
e.printStackTrace();
}
}
}

/**
* 返回指定位置对象
*/
public Object get(int index) {
rangeCheck(index);
Node temp = null;
if(first!=null) {
if(index<(size >> 1)) {
temp = first;
for(int i=0;i<index;i++) {
temp = temp.next;
}
}else {
temp = last;
for(int i=size-1;i>index;i--) {
temp = temp.previous;
}
}

}
return temp.obj;
}

/**
* 在末尾增加对象
* @param obj
*/
public void add(Object obj) {
Node n = new Node();
if(first == null) {
n.previous=null;
n.obj=obj;
n.next=null;

first = n;
last = n;
}else {
n.previous=last;
n.obj=obj;
n.next=null;

last.next=n;
last = n;
}
size++;
}

/**
* 在制定位置增加对象
*/
public void add(int index, Object obj) {
Node temp = null;
if(first!=null) {
temp = first;
for(int i=0;i<index;i++) {
temp = temp.next;
}
}
Node newNode = new Node();
newNode.obj = obj;
if(temp!=null) {
newNode.previous=temp.previous;
newNode.next=temp;
temp.previous=newNode;
newNode.previous.next=newNode;
size++;
}

}

/**
* 删除索引位置的对象
* @param index
*/
public void remove(int index) {
Node temp = null;
if(first!=null) {
temp = first;
for(int i=0;i<index;i++) {
temp = temp.next;
}
}
temp.previous.next=temp.next;
temp.next.previous=temp.previous;
size--;
}

public static void main(String[] args) {
MyLinkedList test = new MyLinkedList();
test.add("111");
test.add("222");
test.add(1,"hhh");
test.add("333");
//test.remove(1);
for(int i=0;i<test.size();i++) {
System.out.println(test.get(i));
}
}

}