<?php
/
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."\n";
}

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."\n";
}
}

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']);

?>