php手册学习的 迭代器 Iterator

<?php 

#迭代器原理演示
class MyIterator implements Iterator{
	#定义一个属性，原来记录执行次数
	private $pos;
	#定义要遍历的数组
	private $arr=array(
		'first_param',
		'secnod_param',
		'third_param'
	);

	#定义构造函数
	public function __construct(){
		$this->pos = 0;
	}

	#定义指针置0 rewind
	public function rewind(){
		echo __METHOD__,"<br/>";
		$this->pos=0;
	}

	#定义valid 方法
	public function valid(){
		#判断是否可行
		echo __METHOD__,"<br/>";
		if(isset($this->arr[$this->pos])){
			return isset($this->arr[$this->pos]);
		}
	}

	#获取当前的值 current
	public function current(){
		echo __METHOD__,"<br/>";
		return $this->arr[$this->pos];
	}

	#获取当前的键值 key
	public function key(){
		echo __METHOD__,"<br/>";
		return $this->pos;
	}

	#指针下移函数
	public function next(){
		echo __METHOD__,"<br/>";
		++$this->pos;
	}

}

#实例化对象
$test = new MyIterator();

#遍历对象
foreach($test as $key=>$val){
	var_dump($key,$val);
	echo '<hr/>';
}