This document discusses various design patterns used in PHP and Joomla, including examples of how they are implemented. It covers creational patterns like factories, structural patterns like MVC and observer, and behavioral patterns. It also discusses anti-patterns to avoid. Joomla's auto-loading and class registration via JLoader is explained as helping performance and simplicity over require statements. Examples are given of how patterns like observer, MVC and strategy are combined in Joomla.

1. PHP Design Patterns
in Joomla!
@yveshoppe

2. Was sind Design Patterns?

3. Allgemein anerkannte
Lösungen für
wiederkehrende Probleme

5. Anti Patterns

6. $_REQUEST anstelle von JInput
Reinventing the square
wheel

7. Mambo / Joomla 1.0
Ball of Mud

8. Als Stackoverflow einen Tag nicht erreichbar
war sank die Produktivität um 80 %!
Copy & Paste

9. Perfekte Lösungen für eine nicht perfekte
Welt!
Overengineering

10. Ein Objekt welche alle Aufgaben und Daten
in sich vereint.
God Object

11. Entwurfsmuster, Antimuster, abstrakte
Fabrik, Schablonenmethode,
Fliegengewicht, Gasfabrik, Wunderwaffe
Translating Design
Patterns into German!

12. Quelle:
Wikipedia.de

13. Geschichte der Design Patterns

14. Gang of Four (1994)
Erich Gamma
Ralph Johnson
Richard Helm
John Vlissides
23 Design Patterns

15. in Kategorien
Einteilung von Design
Patterns

16. $bla = JFilterInput::getInstance()->clean($bla);
$db = JFactory::getDbo();
Creational Patterns

17. Bridge Pattern (Ouptut raw, html, component, feed)
Structual Patterns

18. JTableObserverContenthistory::createObserver($this,
array('typeAlias' => 'com_tags.tag'));
Behavioral Patterns

19. Revisions / Versions in Joomla 3.x!
Observer Pattern

20. Tag History

21. Observer Pattern
Speichern

22. interface JObserverInterface
{
public static function createObserver (
JObservableInterface $observableObject,
$params = array()
);
}
libraries/joomla/observer/interface.php

23. abstract class JTableObserver implements
JObserverInterface
{
public function __construct(JTableInterface $table)
{
$table->attachObserver($this);
..
}
public function onAfterStore(&$result)
{
}
}
libraries/joomla/table/observer.php

24. class JTableObserverContenthistory extends JTableObserver
{
public static function createObserver(JObservableInterface
$observableObject, $params = array())
{
$typeAlias = $params['typeAlias'];
$observer = new self($observableObject);
$observer->contenthistoryHelper = ..;
return $observer;
}
public function onAfterStore(&$result)
{
..
$this->contenthistoryHelper->store($this->table);
}
libraries/joomla/table/observer/contenthistory.php

25. class TagsTableTag extends JTableNested
{
public function __construct($db)
{
parent::__construct('#__tags', 'id', $db);
JTableObserverContenthistory::createObserver
($this, array('typeAlias' => 'com_tags.tag'));
}
libraries/joomla/observer/interface.php

26. Model View Controller
Pattern
Observer, Composite und Strategy Pattern
vereint.

27. MVC Schema

28. Verarbeitung von Aufgaben (tasks) und
Events
Controller

29. class ContentControllerArticle extends JControllerForm
{
public function save($key = null, $urlVar = null)
{
$model = $this->getModel();
$table = $model->getTable();
..
$model->save($validData)
..
$viewType = 'html';
$view = $this->getView($viewName, $viewType, '', array('base_path'
=> $this->basePath, 'layout' => $viewLayout));
$view->display();
administrator/components/com_content/controllers/article.php
Stark vereinfacht!

30. Die Applikations-Logik (CRUD etc)
Model

31. class ContentModelArticle extends JModelAdmin
{
public function save($data)
{
// Filtern, Aufräumen, Plugin Events und Co.
...
$table = $this->getTable();
if (!$table->bind($data))
{
$this->setError($table->getError());
}
..
// Speichern in der Datenbank..
..
return true;
administrator/components/com_content/models/article.php

32. Die Ausgabeschicht
(HTML, RAW, COMPONENT etc.)
View

33. class ContentViewArticle extends JViewLegacy
{
public function display($tpl = null)
{
echo “Erfolgreich gespeichert..”;
administrator/components/com_content/views/article/view.html.php

34. JLoader::register(
'ContentHelper', JPATH_ADMINISTRATOR .
'/components/com_content/helpers/content.php'
);
Auto-Loading (PSR)

35. (statt require(_once))
Warum JLoader?

36. Performance
&
Einfachheit!

37. abstract class JLoader
{
public static function setup($enablePsr = true, $enablePrefixes = true,
$enableClasses = true)
{
..
spl_autoload_register(array('JLoader', 'load'))
spl_autoload_register(array('JLoader', 'loadByPsr0'));
spl_autoload_register(array('JLoader', 'loadByAlias'));
libraries/loader.php

38. abstract class JLoader
{
protected static $classes = array();
public static function register($class, $path,
$force = true)
{
..
self::$classes[$class] = $path;
}
public static function discover($classPrefix, $parentPath, $force = true,
$recurse = false)
{
..
foreach ($iterator as $file)
self::register($class, $file->getPath() . '/' . $fileName);
libraries/loader.php

39. abstract class JLoader
{
public static function load($class)
{
..
include_once self::$classes[$class];
libraries/loader.php

40. JUpdater -> update($type)

41. Fragen?
Vielen Dank!