Dep Injection

depInjection.php

<?php

interface iGame {
	public function start();
	public function end();
	public function move();
}

class tictactoe implements iGame {
	public function start() {
		return 'begin!' . PHP_EOL;
	}
	public function end() {
		return 'game over!' . PHP_EOL;
	}
	public function move() {
		return 'moving...' . PHP_EOL;
	}
}

class advancedTicTacToe {

	public function __construct(tictactoe $game) {
		$this->game = $game;
	}

	public function __call($method, $params) {
		if(in_array($method, array('start', 'end', 'move'))) {
			return $this->game->$method();
		}
		throw new BadMethodCallException('Method ' . $method . ' does not exist');
	}

}

class library {
	public static $instances;

	/**
	 * Will attempt to create a class and give it all it's required parameters
	 * 
	 * @param  string $className
	 * @return object
	 */
	public function create($className) {
		// Generate params
		$params = array();
		if(method_exists($className, '__construct')) {
			// Get params
			$function = new ReflectionMethod($className, '__construct');
			foreach ($function->getParameters() as $param) {
				$name = $param->getName();
				if(!isset(self::$instances[$name])) {
					// Create if it doesn't already exist
					self::$instances[$name] = $this->create($param->getClass()->getName());
				}
				$params[$name] =& self::$instances[$name];
			}

			// Create class
			$ref = new \ReflectionClass($className);
			return $ref->newInstanceArgs($params);
		} else {
			// No constructor
			return new $className();
		}
	}
}

$lib = new library();

$snickers = $lib->create('advancedTicTacToe');

echo $snickers->start(); // begin!
echo $snickers->move(); // moving...
echo $snickers->end(); // game over!