/********************************************************************
    Model-View-Controller implementation according to POSA
    (Pattern-Oriented Software Architecture
      http://www.hillside.net/patterns/books/Siemens/book.html)
    ********************************************************************/
     
    class HelloWorldController {
        private $model;
        function __construct($model) {
            $this->model = $model;
        }
     
        function handleEvent($args) {
            $this->model->setStrategy($args[2]);
            $this->model->addText($args[1]);
        }
    }
     
     
    class HelloWorldModel {
        private $text;
        private $observers = array();
        private $strategy;
        
        function attach($observer) {
            $this->observers[] = $observer;
        }
     
        function getData() {
            $facade = new HelloWorldFacade($this->strategy);
            return $facade->getHelloWorld().$this->text."
    ";
        }
     
        function addText($text='') {
            $this->text = $text;
            $this->notify();
        }
     
        function setStrategy($strategy) {
            $this->strategy = $strategy;
        }
        
        function notify() {
            foreach ($this->observers as $observer) {
                $observer->update();
            }
        }
    }
     
    class HelloWorldView {
        private $model;
     
        function initialize($model) {
            $this->model = $model;
            $model->attach($this);
            return $this->makeController();
        }
     
        function makeController() {
            return new HelloWorldController($this->model);
        }
     
        function update() {
            $this->display();
        }
     
        function display() {
            echo $this->model->getData();
        }
    }
     
     
    /*********************************************************************
    "Business logic"
    ********************************************************************/
     
    class HelloWorld {
       function execute() {
           return "Hello world";
       }
    }
     
    class HelloWorldDecorator {
       private $helloworld;
       function __construct($helloworld) {
           $this->helloworld = $helloworld;
       }
     
       function execute() {
           return $this->helloworld->execute();
       }
    }
     
    abstract class HelloWorldEmphasisStrategy {
        abstract function emphasize($string);
    }
     
    class HelloWorldBangEmphasisStrategy extends HelloWorldEmphasisStrategy {
        function emphasize($string) {
           return $string."!";
        }
    }
     
    class HelloWorldRepetitionEmphasisStrategy extends HelloWorldEmphasisStrategy {
        function emphasize($string) {
           return $string." and ".$string." again";
        }
    }
     
    class HelloWorldEmphasizer extends HelloWorldDecorator {
       private $strategy;
       function HelloWorldEmphasizer($helloworld,$strategy) {
           $this->strategy = $strategy;
           parent::__construct($helloworld);
       }
     
       function execute() {
           $string = parent::execute();
           return $this->strategy->emphasize($string);
       }
    }
     
    class HelloWorldStrategyFactory {
        static function make($type) {
            if ($type == 'repetition') return self::makeRepetitionStrategy();
            return self::makeBangStrategy();
        }
     
        static function makeBangStrategy() {
            return new HelloWorldBangEmphasisStrategy;
        }
        static function makeRepetitionStrategy() {
            return new HelloWorldRepetitionEmphasisStrategy;
        }
    }
     
    class HelloWorldFormatter extends HelloWorldDecorator {
       function execute() {
           $string = parent::execute();
           return $string."
    ";
       }
    }
     
    class HelloWorldFacade {
        private $strategy;
        function __construct($strategyType) {
            $this->strategy = HelloWorldStrategyFactory::make($strategyType);
        }
     
        function getHelloWorld() {
            $formatter = new HelloWorldFormatter(
                    new HelloWorldEmphasizer(
                        new HelloWorld,$this->strategy));
            return $formatter->execute();
        }
    }
     
    $model = new HelloWorldModel;
    $view = new HelloWorldView;
    $controller = $view->initialize($model);
    $controller->handleEvent($_SERVER['argv']);