package com.anxpp.designpattern.iterator;

//方便演示而实现的简陋的单向链表list

public class MyLinkedList<T> implements MyList<T>{

private int size; //存放的元素个数,会默认初始化为0

private Node<T> first; //首节点，默认初始化为null

@Override

public MyIterator<T> iterator() {

return new Iterator();

}

@Override

public boolean add(T t) {

if(size==0){

first = new Node<T>(t,null);

size++;

return true;

}

Node<T> node = first;

while(node.next!=null)

node = node.next;

node.next = new Node<T>(t,null);

size++;

return true;

}

@Override

public T get(int index) {

Node<T> node = first;

while(--index>=0)

node = node.next;

return node.data;

}

@Override

public T remove() {

return remove(size-1);

}

@Override

public T remove(int index) {

if(index<0||index>=size) return null;

Node<T> node = first;

while(--index>0)

node = node.next;

T element = node.next.data;

node.next = node.next.next;

size--;

return element;

}

@Override

public boolean remove(T element) {

if(element == null){

if(first.data==null){

first = first.next;

size--;

return true;

}

Node<T> node = first;

do{

if(node.next.data==null){

node.next = node.next.next;

size--;

return true;

}

node = node.next;

}

while(node.next!=null);

}

else{

if(first.data.equals(element)){

first = first.next;

size--;

return true;

}

Node<T> node = first;

do{

if(node.next.data.equals(element)){

node.next = node.next.next;

size--;

return true;

}

node = node.next;

}

while(node.next!=null);

}

return false;

}

@Override

public boolean set(int index, T element) {

if(index<0||index>=size) return false;

Node<T> node = first;

while(--index>0)

node = node.next;

node.data = element;

return true;

}

@Override

public int size() {

return size;

}

//链表节点

private static class Node<T>{

T data;

Node<T> next;

Node(T data,Node<T> next){

this.data = data;

this.next = next;

}

}

//遍历器

private class Iterator implements MyIterator<T>{

private Node<T> next; //下一个节点

Iterator(){

next = first;

}

@Override

public boolean hasNext() {

return next!=null;

}

@Override

public T next() {

T data = next.data;

next = next.next;

return data;

}

@Override

public T remove() {

// TODO Auto-generated method stub

return null;

}

}

}