protected function loadMappedClass($class)
    {
        list($lowerClass, $upperClass) = $this->normalizeClass($class);

        // Look through registered directories
        foreach ($this->directories as $directory) {

            // If the mapped class exists, require it
            if ($this->isRealFilePath($path = $directory.DIRECTORY_SEPARATOR.$lowerClass.'.php')) {
                $this->requireClass($class, $path);

                return $path;
            }

            if ($this->isRealFilePath($path = $directory.DIRECTORY_SEPARATOR.$upperClass.'.php')) {
                $this->requireClass($class, $path);

                return TRUE;
            }
        }

        // never found it
        return FALSE;
    }