You might have a need for a custom access decision voter when security decisions are made based on who is accessing what domain object. Luckily Spring Security has quite a few options for such implement such access control list (ACL) constraints.
Archive: October 2019
ZIO is a type-safe, composable library for asynchronous and concurrent programming in Scala (from: The ZIO github). The library copes with functional IO, like many Functional Programming libraries do. The added value of ZIO is that the
ZIO[R, E, A] type-constructor
(the main IO monad of the library) acts as an IO monad, an error handling monad, and a reader monad. A functional programming style often needs a combination of these three types to cope with the most common problems when creating an application:
Often you’ll find access decisions move beyond simplistic ownership or having a certain role, for instance when users share domain objects with other users. In such cases it’s common to separate permission to view an instance from being able to make changes to the same instance. When your access rules are relatively straightforward, Spring Security offers the PermissionEvaluator interface to secure instance access.
ZIO is a type-safe, composable library for asynchronous and concurrent programming in Scala (from: The ZIO github). The ZIO framework provides your program as immutable and pure values, which are very simple to properly unit test. But how can you run an integration test to see if your application starts up properly?
Spring Data repositories allow you to easily query your entities with method names such as
However, it can get cumbersome to always retrieve, pass and match on the active user.
Luckily Spring Security integrates well with Spring Data to minimize the overhead.
Spring Data enables you track who modified an entity and when, with just a few annotations. When combined with Spring Security, you can set this metadata based on the active user.
Distributed tracing is a method used to profile and monitor applications, especially those built using a microservices architecture. Distributed tracing helps pinpoint where failures occur and what causes poor performance. Applied to Kafka Streams it allows us to trace and visualize our messages by propagating diagnostic information within message headers.
Using the Stream API and the
map method we can transform elements in a stream to another object. Instead of using the
map method we can also write a custom
Collector and transform the elements when we use the
collect method as terminal operation of the stream.
I have seen the following pattern appear quite a lot:
The Kotlin standard library contains a lot of helper functions on top of the Java standard library for our convenience.
Some of those functions help us in converting between different data types.
For example, the
String.toInt() function converts a number formatted as
String to its
But how do we accomplish the same with a
Char? Spoiler alert: NOT by using
Functions defined in Kotlin companion objects are often seen as the 'equivalent' of static methods in Java. Although there are some similarities, there are also some caveats you should be aware of. For example, how to use method references (or, to be pedantic: function references) to refer to functions defined in a companion object.