php - IteratorAggregate インターフェイス

IteratorAggregate extends Traversable {
    /* 方法 */
    abstract public Traversable getIterator ( void )
}

<?php
    class myData implements IteratorAggregate {
        public $property1 = "Public property one";
        public $property2 = "Public property two";
        public $property3 = "Public property three";
        public function __construct() {
            $this->property4 = "last property";
        }
        public function getIterator() {
            return new ArrayIterator($this);
        }
    }
    $obj = new myData;
    foreach($obj as $key => $value) {
        var_dump($key, $value);
        echo "\n";
    }
?>

string(9) "property1"
string(19) "Public property one"
string(9) "property2"
string(19) "Public property two"
string(9) "property3"
string(21) "Public property three"
string(9) "property4"
string(13) "last property"