A very common scenario in many kinds of software is when the input data is potentially unlimited and it can appear at arbitrary intervals. The common way of handling such cases is using the Observer pattern in it’s imperative form – callbacks.

But this approach creates what’s commonly called “Callback Hell”. It’s a concept basically identical to the more commonly known “GOTO Hell” as they both mean erratic jumps in flow of control that can be very hard to reason about and work with. When writing an application we need to analyze all the callbacks to be sure e.g. we’re not using a value that can be changed by a callback at a random point of time.

But there exists a declarative approach to solving this problem that let’s us reason about it in a much more predictable and less chaotic fashion – Streams. Read more

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Part of the success of modern application is targeting it globally – all over the world. It isn’t possible to run such application on a single machine, even with most powerful hardware.

Definitions like Distributed computing or Reactive applications were born in the process of IT globalization. Nowadays, applications run on multiple virtual machines distributed over multiple physical machines which are often spread around the world. Such applications aren’t easy to maintain.

Every service has different hardware requirements and dependencies, so it has to be deployed and upgraded continuously. In addition each machine has to be configured in such a way that allows communication within the cluster and with external services. Although Devops have helpful deployment tools like Chef, Puppet or Ansible, these tasks still aren’t easy, trust me. Read more

When operating an Akka cluster the developer must consider how to handle network partitions (Split Brain scenarios) and machine crashes. There are multiple strategies to handle such erratic behavior and, after a deeper explanation of the problem we are facing, I will try to present them along with their pros and cons using the Split Brain Resolver in Akka, which is a part of the Reactive Platform. Read more

Back in the days the business was much simpler and required all-in-one straightforward solutions that usually end up as monoliths. Thanks to that supporting those systems was simpler in the beginning, but over the time you had much more chances to end up with a clumsy, tightly coupled system.

Right now markets are changing rapidly. You either adapt quickly or you go out of business. Software has to comply to this new reality.

Changing way you want to develop your system means you need to change your mindset, learn new stuff and apply best practices. This is the place where dedicated platform might help the newcomers. Read more