オブジェクトの反復処理

<?php
class sampleClass
{
    public $varA = '値Ａ';
    public $varB = '値Ｂ';
    public $varC = '値Ｃ';
    protected $varD = '値Ｄ';
    private $varE = '値Ｅ';
    function sampleMethod() {
        echo "<p>sampleClass::sampleMethod</p>";
        foreach( $this as $key => $value ) {
            print "<p>$key => $value</p>";
        }
    }
}
$class = new sampleClass();
foreach( $class as $key => $value ) {
    print "<p>$key => $value</p>";
}
echo "<br />";
$class->sampleMethod();
?>