Welcome to my blog where I write about some of the things I do.
Happy coding!
Recent Posts
Spring Boot JSON API versioning options
(Image by Arek Socha from Pixabay)
One of the common issues when developing an API specification is how to deal with API contract modifications. Hopefully one is very successful and has lots of customers with software clients already using the current version of the spec. so simply dropping the existing version and moving to the new one is not an option, hence the issue.
Spring Boot, with its automatic JSON mapping with Jackson, is a very productive framework to develop APIs, but one still has to face the problem on how to adapt the code to support several API versions with the same code base.
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XML/XSLT 3.0 development with Spring Boot, Saxon and Summer
(Image by James Osborne from Pixabay)
In this entry, I am going to explain how you can develop web applications using Spring Boot using XSLT 3.0 as a view technology. The XSLT 3.0 processor I’m going to be using is Saxon as that is the only working Java implementation I’m aware of. To facilitate development, I will add my own library to the mix, GreenSummer, because it’s the one I’m most familiar with.
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Easily connecting your Spring Boot applications to the Elastic Stack with Log4j2
Now that logging aggregators are becoming ubiquitous, a common issue that we, developers, have to face is how to connect the log output of our applications to those tools. Some of the issues that we encounter during that process are:
· Usually we don’t use an aggregator in development, we simply want to see all the logs in the development console, so the application has to start without issues when there is no aggregator listening.
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Real life Java: From numbers to localized text ordinals using ICU4J
Recently, I had to build a Java application that reads a series of data and puts “human readable” labels on it. Some of the texts the application has to generate use ordinals like “This is the _first _report…” and they have to be displayed in three different languages, so instead of using a non-scalable solution (if/else, switch), I decided to generate the messages from the numeric data using something more flexible.
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Real life Java: Aggregating nested collection with streams
Most of the times I had used the “relatively new” streams in Java, it was for straight-forward tasks with operations on one stream. I sometimes use more sophisticated collectors, like Collectors.toMap, but recently I had to use more complicated stuff to solve a real problem and I thought it might interesting writing about it, as the examples one usually reads about are synthetic and lack the focus of solving a real problem.
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SpringBoot, Maven, Jenkins & Git: How to identify your release automagically
One of the issues that usually comes up when you have an application up & running is finding out what’s deployed in the different servers so you can know if what you committed in the source code repository is deployed in those releases or not.
That thing that sounds so trivial becomes not that easy when you add automatic deployment, branches and everything that allows you to be “agile”, so you need to add some automatic mechanisms to your release and deployment process in order to make it easy again.
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Quick tip: Elasticsearch + Consul + health check + basic authentication
Recently, I’ve been installing the “Elastic Stack”, previously known as ELK, and one of the steps took me a while to figure it out, due to outdated documentation and missing pieces in the examples for the specific syntax that you need to get right, so here it comes:
Imagine you have already gone through the Elastic Stack quick start and you have it secured with basic authentication, either directly through the configuration or through the recommended X-Pack plugin.
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Spring Boot: Setting a unique ID per request
Spring Boot web applications, like many others unless you go for the mono-threaded option (yuck!) serve requests concurrently. That brings many advantages, but one of the drawbacks that come with it is that it makes harder to trace what each request is doing, as it is doing it while other requests are doing other, often similar, things. That hurts logging information badly, as the messages generated for one request can easily be intermingled with other messages generated for other requests.
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Configuring Multiple TTL Caches in Spring Boot dinamically
Recently, I started using Spring caching in my Spring Boot applications and I came across a very nice entry in Daniel Olszewski’s blog (MULTIPLE TTL CACHES IN SPRING BOOT) that indeed explains how to set up multiple caches in Spring Boot with a specified TTL (Time To Live) setting and is really worth reading it as it even explains how to test the functionality. So, if you have not read it already, I invite you to do go ahead and do it now, as I’ll build on top of that.
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X-Factor Apps using the Spring Boot ecosystem, an overview
Summary Nowadays, there are tons of literature and virtual ink written about how to develop for the cloud and make your applications Internet-scale. But how about those of us where the scale of our problems do not fit such model? Well, even if you are not developing for the cloud and you don’t need to go full scale with the Twelve-Factor App recommendations, there are still many benefits that can still be enjoyed by sticking to the main principles behind them.
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