Router functions play a similar role in Spring Webflux as controllers in Spring MVC. Both are responsible for handling HTTP requests/responses. However, compare to controllers, new approach is not represented by a single component, but consists of two parts: a router function and a handler, which serves as glue between service (business logic) and HTTP […]
In Spring MVC a server-side validation was implemented using annotations. We could just put @Valid before the body payload in the controller method and Spring did all dirty work for us. On the other side, Spring Webflux implements a functional-style web layer, which is based on router functions and handlers. This is non-blocking API and […]
The iterator pattern is one of approaches to access elements of a collection, alongside with streams. From a technical point of view, the iterator traverses elements in a sequential and predictable order. In Java the behavior of iterators is defined in java.util.Iterator contract, which is a member of Java Collections Framework. Iterators are similar to […]
Eclipse Vertx is a robust technology to build reactive microservices or serverless functions. When you develop such applications, the role of server side validation rises. In traditional web applications we combine both client-side and server-side validation techniques. However, in API world we can be in situations without clients (when you have a public API). We […]
When you are working on any somehow complex application, you need to enable validation. For example, if user submits a form or a request, your app should check, that data is in an appropriate format and required fields are not missed. When user signs up, we need to validate that an email address is proper […]
Recently I started to learn Clojure, and usually, my first phase is to complete small programming exercises. To practice Clojure I decided to solve some CodingBat problems. A common task here is to check, if an array does contain some value. The expected result should be a boolean value. When I moved to practical implementations, […]
In some form or another, but exceptions exist in almost any languages. Due to the fact, that Clojure actually runs on JVM, it inherits its exception system from Java. From a technical point of view, the exception concept stands for unwanted or unexpected event, which occurs during the execution of a program i.e at run […]
An authentication with tokens became a must-have feature for modern web apps. It suits natively to single page applications and mobile applications. While Spring is de facto standard in Java ecosystem, there are developers, who prefer to use alternative solutions. This is true, because Spring is quite heavy platform and there is a number of […]
When we talk about Java collections, we consider two things. First, more wide concept, means implementations of common data structures. An another, narrow understanding, corresponds to concrete interfaces and their implementations, that are contained in Java Collections Framework, supplied out-of-the box. In that sense, we need to remember that such collections inherit to the root […]
In the previous post we have already talked about authentication in Spring Webflux. We implemented a component, that contains a required business logic to process login and signup, and to issue JWT. However, to fullfil this security flow, we also need a component, that we assert a token: extract Authorization header from HTTP request and […]