如何访问子类对象内的值？

I have sub class and i want access value, but I do not know how and I am a beginner in php programming.

code in php :

function initDisplay($parent) {  // $parent type Vtiger_PDF_Generator 
    $pdf = $parent->getPDF();
    $contentFrame = $parent->getContentFrame();

The following details of Vtiger_PDF_Generator :

Vtiger_PDF_Generator object {
 headerViewer => Vtiger_PDF_InventoryHeaderViewer object {
model => Vtiger_PDF_Model object {
  values => array(2) (
  ) ....  

i want get value array in sub class Vtiger_PDF_Model from parent class Vtiger_PDF_Generator.

I attach image to clarify this problem

Please guide me, Thanks.

Assuming these variable are public accessible you can access first item of the values array,

$parent->headerViewer->model->values[0]->title

or you can loop

$valuesArray= $parent->headerViewer->model->values;
foreach ($valuesArray as $value)
{
  echo $value->title;
}