<?php
namespace Tools;
/*
迭代器模式
迭代器模式，在不需要了解内部实现的前提下，遍历一个聚合对象的内部元素
相比于传统的编程模式，迭代器模式可以影藏遍历元素的所需的操作
*/
class AllUser implements \Iterator{
/*
* iterator接口中有5个方法，实现了iterator的类都可以foreach
current()—返回当前元素值,
key()—返回当前元素的键值,
next()—下移一个元素,
valid()—判定是否还有后续元素, 如果有, 返回true,
rewind()—移到首元素.
*/
private $users = array();
protected $index;
public function __construct()
{
$db = mysqli_connect("localhost","root","","test");
$res = $db->query("select * from user");
$this->users = $res->fetch_all(MYSQLI_ASSOC);
}
//current()—返回当前元素值,
public function current()
{
return $this->users[$this->index];
}
//key()—返回当前元素的键值,
public function key()
{
return $this->index;
}
//next()—下移一个元素,
public function next()
{
$this->index++;
}
//valid()—判定是否还有后续元素, 如果有, 返回true,
public function valid()
{
return $this->index < count($this->users);
}
//rewind()—移到首元素.
public function rewind()
{
$this->index = 0;
}
}
$users = new \Tools\AllUser();
foreach($users as $user){
print_r($user);
}
