public function setAdapter($adapter, $options = null)
    {
        $adapter = ucfirst(strtolower($adapter));

        if (Zend_Loader::isReadable('Zend/Validate/Barcode/' . $adapter. '.php')) {
            $adapter = 'Zend_Validate_Barcode_' . $adapter;
        }

        if (!class_exists($adapter)) {
            Zend_Loader::loadClass($adapter);
        }

        $this->_adapter = new $adapter($options);
        if (!$this->_adapter instanceof Zend_Validate_Barcode_AdapterInterface) {

            throw new Zend_Validate_Exception(
                "Adapter " . $adapter . " does not implement Zend_Validate_Barcode_AdapterInterface"
            );
        }

        return $this;
    }