Francesco-itembase

Long itemId = 42L;
BigDecimal vatRate = BigDecimal.of(0.42);

// error handling is omitted for brevity
return fetchItem(itemId)
    .flatmap(item -> calculateTax(item, vatRate))
    .flatmap(BusinessClass::writeTaxToDB);

Francesco-itembase

// AppRouter.java
@Configuration
public class AppRouter {
    // works for a single bean
    @Bean
    public RouterFunction<ServerResponse> routes(ResouceHandler resourceHandler) {
        return RouterFunctions.route(GET("/resource/{id}").and(accept(APPLICATION_JSON)), resourceHandler::get)
            .andRoute(GET("/resource/filter/{filterQuery}").and(accept(APPLICATION_JSON)), resourceHandler::getFiltered);
    }
}