public function read_items( $order, $type ) {
		global $wpdb;

		// Get from cache if available.
		$items = 0 < $order->get_id() ? wp_cache_get( 'order-items-' . $order->get_id(), 'orders' ) : false;

		if ( false === $items ) {
			$items = $wpdb->get_results(
				$wpdb->prepare( "SELECT order_item_type, order_item_id, order_id, order_item_name FROM {$wpdb->prefix}woocommerce_order_items WHERE order_id = %d ORDER BY order_item_id;", $order->get_id() )
			);
			foreach ( $items as $item ) {
				wp_cache_set( 'item-' . $item->order_item_id, $item, 'order-items' );
			}
			if ( 0 < $order->get_id() ) {
				wp_cache_set( 'order-items-' . $order->get_id(), $items, 'orders' );
			}
		}

		$items = wp_list_filter( $items, array( 'order_item_type' => $type ) );

		if ( ! empty( $items ) ) {
			$items = array_map( array( 'WC_Order_Factory', 'get_order_item' ), array_combine( wp_list_pluck( $items, 'order_item_id' ), $items ) );
		} else {
			$items = array();
		}

		return $items;
	}