JDriven Blog

Clojure Goodness: Reading Text File Content With slurp

Posted on by  
Hubert Klein Ikkink

The slurp funtion in Clojure can be used to read the contents of a file and return it as a string value. We can use several types as argument for the function. For example a string argument is used as URI and if that is not valid as a file name of the file to read. A File instance can be used directly as argument as well. But also Reader, BufferedReader, InputStream, URI, URL, Socket, byte[] and char[]. As an option we can specify the encoding used to read the file content using the :encoding keyword. The default encoding is UTF-8 if we don’t specify the encoding option.

Continue reading →

K8s cluster on Apple Silicon

Posted on by  
Casper Rooker

I use a local Kubernetes cluster to help me develop microservices. On my 2015 Macbook Pro, the cluster ran inside a Minikube VM using the Hyperkit driver. Replicating this setup on my new 2021 Macbook Pro proved impractical. This is how I made it work.

Continue reading →

DataWeave Delight: Using the update Operator to change values in an object

Posted on by  
Hubert Klein Ikkink

DataWeave has some very nice features to transform data objects. One of those nice features is the update operator. With the update operator we can change values of keys in an object using a very concise syntax. We don’t have to go through all keys and create a new object, but we can pinpoint the exact key and change the value. To get the correct key we use selectors. Once we have the key we can set a new value. We can define a variable to contain the current value if we want to use it to define a new value. Also is it possible to add a condition that needs to be true to change the value. Finally the update operator supports upserting a value if the key might not exist yet.

Continue reading →

Overloading the Primary Constructor in Kotlin for Java Interoperability

Posted on by  
Riccardo Lippolis

One of the great features of Kotlin is its interoperability with Java code. This allows you to easily call 'traditional' Java code from your Kotlin code, but it also helps you the other way around: calling Kotlin code from Java.

Sometimes, a little extra work is needed to make some shiny Kotlin feature work with Java code. For example, Kotlin supports default parameter values, which are not supported in Java. In this case, the @JvmOverloads annotation can be used to generate overloads for functions that contain parameters with default values. This annotation does not only work on functions, but can also be applied on constructors. In this post I will explain how to use this feature on the primary constructor, as it might be confusing where to place the annotation.

Continue reading →

Automatically migrate WebSecurityConfigurerAdapter

Posted on by  
Tim te Beek

If you’ve been working with Spring Security for a while, it should come as no surprise that from time to time, they deprecate the old, and guide you towards the new. In 5.7.x such a change involves the often used WebSecurityConfigurerAdapter.

In Spring Security 5.7.0-M2 we deprecated the WebSecurityConfigurerAdapter, as we encourage users to move towards a component-based security configuration.

And while there are blog posts, release notes, and even an instruction video to highlight the required changes, in the end you will have to change your code. But what all those sources so far have failed to cover, is that there’s now also an easier way to migrate your code, using OpenRewrite.

Continue reading →

shadow-left