Passing control down to component

Calendar.php

<?php

class Calendar extends Page {
  public static $has_many = array(
    'Years' => 'Year'
  );

}

class Calendar_Controller extends Page_Controller {

}

Event.php

<?php

class Event extends DataObject {
  public static $has_one = array(
    'Year'     => 'Calendar',
    'EventPDF' => 'File'
  );
}

class Event_Controller extends Controller {

}

Year.php

<?php

class Year extends DataObject {
  public static $has_one = array(
    'Calendar'  => 'Calendar',
    'YearPDF'   => 'File'
  );

  public static $has_many = array(
    'Events'  => 'Event'
  ); 

}

class Year_Controller extends Controller {

}