PHP - Detailed explanation of IteratorAggregate interface

IteratorAggregate extends Traversable {
	abstract public Traversable getIterator ( void )
}

<?php
/**
 * 利用聚合式迭代器，并返回一个实现了Iterator接口的类的实例
 *
 * @author 疯狂老司机
 */
class myData implements IteratorAggregate {
    public $one = "Public property one";
    public $two = "Public property two";
    public $three = "Public property three";

    public function __construct() {
        $this->last = "last property";
    }

    public function getIterator() {
        return new ArrayIterator($this);
    }
}

$obj = new myData;

foreach($obj as $key => $value) {
    var_dump($key, $value);
    echo '<br>';// Linux：echo "\n";
}
?>