Implementing Lagom Readside Persistence Using Slick

Persistent Entities in Lagom hold state of individual entities. In other words, they cannot be used to serve queries that span more than single entity. This requires us to create another view of the data that is tailored to serve rather optimized queries that span over multiple entities, which brings…

Mapping Exceptions To Idiomatic Http Responses In Lagom

In the last post we saw how Lagom provides us a default exception serializer out of the box to help us translate exceptions to appropriate HTTP responses in Json. We also learnt how Lagom treats exception translations differently when in production and in development as part of it's built in…

Exception Serialization In Lagom

Lagom is an open source framework for building systems of Reactive microservices both in Java or Scala. It provides many out of the box although opinionated APIs, implementation of supporting features and appropriate defaults to build, test and deploy entire systems of Reactive microservices at a fast, yet reliable pace.…

Code Design Template For Apache POI Based Excel Writers

In this blog post I will be proposing a code design template (in Scala) that I have come up with in a very short but fulfilling experience working on a small project based on Apache POI. If you have ever worked with a library like Apache POI, you might have…

Understanding Factories To Create Actors In Akka

In this blog post, we will be discussing factory pattern use cases and implementations in Akka to create actors. Factory of Actors As we already know, in order to create an actor, we need to instantiate an object of akka.actor.Props class with all the configurations needed to create…

Rescheduling Akka Schedulers

This blog post is an afterthought of myself working on Akka Schedulers in an official project. The objective here is to convey the challenges that one may face while working with scheduling/rescheduling Akka Schedulers. On this journey of ours to understand scheduling/rescheduling Akka Schedulers, we will be discussing…

Covariance & Contravariance in Scala: Connecting Dots

In this post we will try to fathom the concepts of covariance and contravariance in bare bones. We won't be discussing the advantages and disadvantages of variance and things like that in this post. You can find better posts online. This post deliberately doesn't discuss real world metaphors to keep…