简单的单向链表的java实现

链表的实现一个是node，一个是List。node是链表每个基本组成部分，List操作node。我的思路大概是这样。

node部分代码：

class Node{
	private Object data;
	private Node next;
	
	public Node(Object data){
		this.data = data;
	}
	
	public void setNext(Node next){
		this.next = next;
	}
	
	public void setData(Object data){
		this.data = data;
	}
	public Object getData(){
		return this.data;
	}
	
	public Node getNext(){
		return this.next;
	}
}

List实现一系列对链表的操作：

class List{
	private Node root;
	private Node point;
	private int count;
	
	public void add(Node node){
		if(root == null){
			this.root = node;
			this.point = node;
		}else{
			this.point.setNext(node);
			this.point = node;
		}
		this.count ++;
	}
	
	public int size(){
		return this.count;
	}
	
	public boolean isEmpty(){
		return this.root == null ? true : false;
	}
	
	public boolean contain(Object data){
		return isContain(this.root,data);
	}
	
	public Object getData(int index){
		if(index<0||index>=this.count){
			return null;
		}
		return getDataByIndex(this.root,0,index);
	}
	
	public void setData(Object data,int index){
	if(index<0||index>=this.count){
		return;
	}
		setDataByIndex(this.root,0,index,data);
	}
	
	public void deleteData(Object data){
		if(this.contain(data)){
			deleteNodeByData(this.root,data);
		}
		return;
	}
	
	
	public void deleteNode(int index){
		if(index<0||index>=this.count){
			return;
		}
		deleteNodeByIndex(this.root,0,index);
	}
	
	public Object[] toArray(){
		Object[] array = new Object[this.count];
		toArrayBy(this.root,array,0);
		return array;		
	}
	
	
	public void clear(){
		this.root = null;
		this.count = 0;
		System.gc();
	}
	
	public void deleteNodeByData(Node node,Object data){
		if(data.equals(this.root.getData())){
			this.root = this.root.getNext();
			this.count--;
			return;
		}
		if(data.equals(node.getNext().getData())){
			node.setNext(node.getNext().getNext());
			this.count--;
			return;
		}
		deleteNodeByData(node.getNext(),data);
	}
	
	private void toArrayBy(Node node,Object[] array,int point){
		if(node == null){
			return;
		}
		array[point] = node.getData();
		toArrayBy(node.getNext(),array,++point);	
	}
	
	private void deleteNodeByIndex(Node node,int point,int index){
		if(index == 0){
			this.root = this.root.getNext();
			this.count--;
			return;
		}
		if(point == index-1){
			node.setNext(node.getNext().getNext());
			this.count--;
			return;
		}
		deleteNodeByIndex(node.getNext(),++point,index);
	}
	
	private void setDataByIndex(Node node,int point,int index,Object data){
		if(point == index){
			node.setData(data);
			return;
		}
		setDataByIndex(node.getNext(),++point,index,data);
	}
	
	private Object getDataByIndex(Node node,int point,int index){
		System.out.println("point="+point);
		System.out.println("index="+index);
		if(point == index){
			return node.getData();
		}
		return getDataByIndex(node.getNext(),++point,index); // ++ can not use behind point
	}
	
	private boolean isContain(Node node,Object data){
		if(node == null){
			return false;
		}
		if(data.equals(node.getData())){
			return true;
		}
		return isContain(node.getNext(),data);
	}
	
	private void print(Node node){
		if(node == null){
			return;
		}
		System.out.println(node.getData());
		print(node.getNext());
	}
	
	public void printAll(){
		print(this.root);
	}
} 

测试代码：

public class TestDemo{
	public static void main(String[] args){
		List list = new List();
		
		System.out.println(list.isEmpty());
		System.out.println(list.size());
		
		list.add(new Node("first"));
		list.add(new Node("second"));
		list.add(new Node("third"));
		
		Object[] array = list.toArray();
		for(int i = 0;i<array.length;i++){
			System.out.println(i+"="+array[i]);
		}
		
		
		System.out.println(list.size());
		System.out.println(list.isEmpty());
		
		list.printAll();
		
		System.out.println("isContain first:"+list.contain("first"));
		System.out.println("isContain other:"+list.contain("other"));
		
		System.out.println("getdata1:"+list.getData(1));
		
		list.setData("none",0);
		list.printAll();
		
		list.deleteNode(0);
		list.printAll();
		
		list.deleteNode(1);
		list.printAll();	
		System.out.println(list.size());
		
		list.deleteData("none");
		list.deleteData("third");
		list.printAll();
		System.out.println(list.size());
		
		list.deleteData("second");
		//list.deleteData("third");
		list.printAll();
		System.out.println(list.size());
		//System.out.println("getdata3:"+list.getData(3));
		
	}
}

这个就是一个简单的实现，对于其中的一些算法的实现没有做比较深的研究。有时间去研究一下java实现List的源码。

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