Micronaut Service with Groovy & Spock

Micronaut supports Java, Groovy and Kotlin languages. In this post let's explore creating a service using Groovy language and Spock testing framework. If you don't have the Micronaut CLI installed, this post has the details of how to get it installed. 1.1.0 is the latest version of Micronaut…

Groovy Power Assert

When I googled for 'power assert', the first result found was the JavaScript library power assert. The second link contains an interview with the author of this library. He acknowledges the inspirations from Groovy ecosystem. Borrowing good ideas from another language/ ecosystem has had positive influence on many languages. Let's…

Micronaut Configuration for CLI

In my previous post we saw how to create a service using micronaut CLI. When you create an application/project using the CLI command mn, the preferences you entered are saved in a file named 'micronaut-cli.yml', which can be found at the project top level directory. Let's take a…

Groovy Execute Around Pattern

In my previous post, we saw how languages with higher order functions make the implementation of Command Pattern very trivial. With a slight modification, we can achieve the Execute Around pattern. Suppose we have two types of transactions (atomic operations). Let's represent them using closures transactionOne and transactionTwo respectively. Now…

Command Pattern in Groovy using Closures

Command Pattern is one of the design patterns published in the GoF book. Command pattern is essentially encapsulating various types of request under a unified interface. The goal here is to minimise the coupling between executor and the client, with the system retaining the ability to evolve with new commands.…

Groovy - Strategy Pattern using Closures

Suppose we have a list of numbers. def numbers = [1, 2, 3, 4, 5, 6, -1] We are asked to do the following Find out all the even numbers in the listFind out all the numbers divisible by 3Find out all the negative numbers in the listLet's write a function…

Groovy - Converting Methods to Closures

One of the important characteristics of Groovy closure is that they are first class - closures can be passed as arguments to other closures and functions. More details on higher order functions in this post.Suppose you have a piece of functionality available as a method and you want to…

Groovy Inline Closures

Consider the following closure sum and it's use in inject method. def numbers = [1, 2, 3, 4, 5, 6, 7] def sum = { number1, number2 -> number1 + number2 } println numbers.inject(0, sum) // 28 If you are not familiar with Groovy closures, this post has the details.In the above…