OBSERVER PATTERN ORIENTÉ DÉVELOPPEMENT ÉVÉNEMENTIEL DÉCLARATIF

<?php

	/**
	 * Observer Design Pattern
	 * @author I. CHIRIAC 
	 * @package Events	 	 
	 */	 	 	
	require_once('events.lib.php');

	class MyEventArg extends EventArgs {
		public $counter = 0;
	}

	/**
	 * Defines a basic observable object   
	 */	 	
	class observable extends ObservableBase {
		/**
		 * Defines event const 
		 * Important : events names definition must start with evt		 
		 */		 		
		const evtDoSomeThing = 1;
		// define a simple instance variable
		public $name;
		// constructor
		public function __construct($name) { $this->name = $name; }		 
		/**
		 * Defines an object action who will raise an event
		 */		 		
		public function doSomeThing() {
			// Raising event by passing constant definition
			$this->raiseEvent(self::evtDoSomeThing, new MyEventArg());
		}	
	}
	
	/**
	 * Defines a basic observer
	 */	 	
	class observer {
		public function __construct(observable $observable) {
			$observable->onDoSomeThing(
				array(
					$this, 
					'HandleSomeThing'
				)
			);
		}
	  public function HandleSomeThing(observable &$sender, MyEventArg &$args) {
			$args->counter ++;
			echo 'Observer can catch that '.$sender->name.' was doing something / '.$args->counter.' <br />';
		}
	}
	
	/**
	 *	DEFINES A STATIC EVENT : FOR ALL INSTANCES
	 */
	
	// FOR PHP 5.x to 5.3
	observable::attach(observable::evtDoSomeThing, 'HandleDoSomeThing');
  // FOR PHP 5.3 and SUP
	// observable::onDoSomeThing('HandleDoSomeThing');


	// DO ACTIONS
	$toto = new observable('toto');

	/**
	 * Defines a specific instance event for toto
	 */	 	
	$toto->onDoSomeThing('TotoDoSomeThing');

	/**
	 * Creating an object
	 */	 	
	$observer = new observer($toto);
	
	// CALLING 
	$toto->doSomeThing();
	
	/**
	 * Create another instance
	 */	 	
	$titi = new observable('titi');
	$titi->doSomeThing();

	/**
	 * DEFINE EVENTS
	 */	 	
	function HandleDoSomeThing(observable &$sender, MyEventArg &$args) {
		$args->counter ++;
		echo $sender->name.' was doing some thing / '.$args->counter.'...<br />';
	}
	function TotoDoSomeThing(observable &$sender, MyEventArg &$args) {
		$args->counter ++;
		echo'Go on toto / '.$args->counter.' !<br />';
		$args->stopBubble();
	}


?>