SourceMaking

<?php

 

abstract class AbstractBookTopic {

    abstract function getTopic();

    abstract function getTitle();

    abstract function setTitle($title_in);

}

  

class BookTopic extends AbstractBookTopic {

    private $topic;

    private $title;

    function __construct($topic_in) {

      $this->topic = $topic_in;

	  $this->title = NULL;

    }

    function getTopic() {

      return $this->topic;

    }

    //this is the end of the chain - returns title or says there is none

    function getTitle() {

      if (NULL != $this->title) {

        return $this->title;

      } else {

        return 'there is no title avaialble';

      }

    }

    function setTitle($title_in) {$this->title = $title_in;}

}

 

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;}

}

 

class BookSubSubTopic extends AbstractBookTopic {

    private $topic;

    private $parentTopic;

    private $title;

    function __construct($topic_in, BookSubTopic $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;}

}

 

  writeln("BEGIN TESTING CHAIN OF RESPONSIBILITY PATTERN");

  writeln("");

 

  $bookTopic = new BookTopic("PHP 5");

  writeln("bookTopic before title is set:");

  writeln("topic: " . $bookTopic->getTopic());

  writeln("title: " . $bookTopic->getTitle());

  writeln("");

 

  $bookTopic->setTitle("PHP 5 Recipes by Babin, Good, Kroman, and Stephens");

  writeln("bookTopic after title is set: ");

  writeln("topic: " . $bookTopic->getTopic());

  writeln("title: " . $bookTopic->getTitle());

  writeln("");

  

  $bookSubTopic = new BookSubTopic("PHP 5 Patterns",$bookTopic);

  writeln("bookSubTopic before title is set: ");

  writeln("topic: " . $bookSubTopic->getTopic());

  writeln("title: " . $bookSubTopic->getTitle());

  writeln("");

 

  $bookSubTopic->setTitle("PHP 5 Objects Patterns and Practice by Zandstra");

  writeln("bookSubTopic after title is set: ");

  writeln("topic: ". $bookSubTopic->getTopic());

  writeln("title: ". $bookSubTopic->getTitle());

  writeln("");

  

  $bookSubSubTopic = new BookSubSubTopic("PHP 5 Patterns for Cats",

    $bookSubTopic);

  writeln("bookSubSubTopic with no title set: ");

  writeln("topic: " . $bookSubSubTopic->getTopic());

  writeln("title: " . $bookSubSubTopic->getTitle());

  writeln("");

 

  $bookSubTopic->setTitle(NULL);

  writeln("bookSubSubTopic with no title for set for bookSubTopic either:");

  writeln("topic: " . $bookSubSubTopic->getTopic());

  writeln("title: " . $bookSubSubTopic->getTitle());

  writeln("");

 

  writeln("END TESTING CHAIN OF RESPONSIBILITY PATTERN");

 

  function writeln($line_in) {

    echo $line_in."<br/>";

  }

?>