简单实现Java中的LinkedList

package com.cym.collection;

public class MyLinkedList {
	private Node first ;
	private Node last;
	private int size;
	public void add(Object obj){
		Node temp = new Node();
		if (first==null) {
			temp.setPrevious(null);
			temp.setContent(obj);
			temp.setNext(null);
			
			first = temp;
			last = temp;
		}else{
			temp.setPrevious(last);
			temp.setContent(obj);
			temp.setNext(null);
			
			last.setNext(temp);
			last = temp;
		}
		size++;
	}
	public int size(){
		return size;
	}
	public Object get(int index){
		rangeCheck(index);
		Node tempNode = node(index);
		return tempNode.content;
	}
	
	public boolean remove(int index){
		rangeCheck(index);
		Node tempNode = node(index);
		
		Node prev = tempNode.previous;
		Node next = tempNode.next;

		//首尾节点检测
		if(prev!=null)
			prev.setNext(next);
		if(next!=null)
			next.setPrevious(prev);
		size--;//切记
		return true;
	}
	
	public void add(int index,Object obj){
		rangeCheck(index);
		Node tempNode = node(index);
		
		Node newNode = new Node();
		newNode.setPrevious(tempNode.getPrevious());
		newNode.setContent(obj);
		newNode.setNext(tempNode.getNext());
		
		Node prev = tempNode.previous;
		Node next = tempNode.next;

		//首尾节点检测
		if(prev!=null)
			prev.setNext(newNode);
		if(next!=null)
			next.setPrevious(newNode);
		
	}
	
	public void set(int index,Object obj){
		rangeCheck(index);
		Node tempNode = node(index);
		
		tempNode.setContent(obj);
		
	}
	private Node node(int index) {
		Node tempNode = null;
		if (index<size>>1) {
			tempNode = first;
			for (int i = 0; i < index; i++) {
				tempNode = tempNode.next;
			}
		}else {
			tempNode = last;
			for (int i = size-1; i >index; i--) {
				tempNode = tempNode.previous;
			}
		}
		return tempNode;
	}
	
	
	private void rangeCheck(int initialCapacity) {
		if (initialCapacity<0) {
			try {
				throw new Exception();
			} catch (Exception e) {
				e.printStackTrace();
			}
		}
		
	}
	
}
class Node{
	Node previous;
	Node next;
	Object content;
	public Node getPrevious() {
		return previous;
	}
	public void setPrevious(Node previous) {
		this.previous = previous;
	}
	public Node getNext() {
		return next;
	}
	public void setNext(Node next) {
		this.next = next;
	}
	public Object getContent() {
		return content;
	}
	public void setContent(Object content) {
		this.content = content;
	}
	
}