callback demo

callback.php

<?php
class person {
	public $name;
	public $price;
	function __construct($name, $price) {
		$this->name = $name;
		$this->price = $price;
	}
}

/**
 *
 */
class ProcessSale {
	private $callbacks = array();
	function __construct() {
		# code...
	}
	function registerCallback($callBack) {
		if (!is_callable($callBack)) {
			throw new Exception('can not call it');
		}
		$this->callbacks[] = $callBack;
	}
	function sale($product) {
		print "{$product->name}:progressing \n";
		foreach ($this->callbacks as $callback) {
			call_user_func($callback, $product);
			// $callback($product);
		}
	}
}

$loger = create_function('$product', 'print $product->name."\n";');
$processor = new ProcessSale();
$processor->registerCallback($loger);
$processor->sale(new person('shoes', 6));
print "\n";
$processor->sale(new person('djfiid', 9));