gistfile1.aw

<?php
interface ApiErrorCode {
	const WRONG_ACTION = 0;
	const WRONG_PARAMETERS_SET = 1;
	public function getError();
}

interface ChartusApiErrorCode extends ApiErrorCode {
	const WRONG_USER_CREDENTIALS = 2;
	const CANT_RETRIEVE_AUTH_TOKEN = 3;
}

class ApiError implements ApiErrorCode {
	
	public $message;
	public $code;

	/** @var ApiError */
	protected static $_instance;
	protected $messageByCode;

	protected function init() {
		$this->messageByCode = array(
			self::WRONG_ACTION => 'Wrong action',
			self::WRONG_PARAMETERS_SET => 'Wrong parameters set',
		);
	}

	protected function __construct() {
		$this->init();
	}

	public static function instance() {
		if(self::$_instance === null) {
			self::$_instance = new ApiError();
		}
		return self::$_instance;
	}
	
	public function getError($errorCode) {
		$this->code = $errorCode;
		$this->message = $this->messageByCode[$errorCode];
		return $this;
	}
}

class ChartusApiError extends ApiError {
	
	public static function instance() {
		if(self::$_instance === null) {
			self::$_instance = new ChartusApiError();
		}
		return self::$_instance;
	}

	protected function init() {
		parent::init();
		$this->messageByCode = array_merge($this->messageByCode, array(
			self::WRONG_USER_CREDENTIALS => 'Wrong user credentials.',
			self::CANT_RETRIEVE_AUTH_TOKEN => 'Can\'t retrieve authentication token',
		));
		
	}
}

// usage like:
class MyClass {

	protected function myMethod() {
		$error = ChartusApiError::instance()
			->getError(ChartusApiErrorCode::WRONG_USER_CREDENTIALS);
	}

	protected function throwError(ApiError$error,
			$className = 'ChartusApiException') {
		throw new $className($error->message, $error->code);
	}
}