<?php

//copyright Lawrence Truett and FluffyCat.com 2005, all rights reserved
  
  class BookSubTopic extends AbstractBookTopic {

    private $topic;
	private $parentTopic;
    private $title;

    function __construct($topic_in, BookTopic $parentTopic_in) {
      $this->topic = $topic_in;
      $this->parentTopic = $parentTopic_in;
	  $this->title = NULL;
    }

    function getTopic() {return $this->topic;}

    function getParentTopic() {return $this->parentTopic;}	

    function getTitle() {
      if (NULL != $this->title) {
        return $this->title;
      } else {
        return $this->parentTopic->getTitle();
      }
    }
    function setTitle($title_in) {$this->title = $title_in;}

  }

?>