Awaitility VS fastexcel

I’ve coded in Java since the first beta, even back then threads were at the top of my list of favorite features. Java was the first language to introduce thread support in the language itself, it was a controversial decision back then. In the past decade, every language raced to include async/await and even Java had some third-party support for that… But Java zigged instead of zagging and introduced the far superior virtual threads (project Loom). This post isn’t about that.

I hope everybody knows https://github.com/awaitility/awaitility by now.

And finally the tests, using Awaitility as we are testing asynchronous stuff:

awaitability: A tool to express expectations for asynchronous system in an easy and concise manner.

Awaitility with version 4.1.0 comes with fail fast feature (2m read) 🎉 https://github.com/awaitility/awaitility/wiki/Usage#fail-fast-conditions

Given our new functionality to update the membership list, we can create a new test case where two nodes join the cluster and expect that to be reflected in the local state of each node eventually. Thanks to the Awaitility DSL we can conveniently wait for the eventual update to happen.

Nota: para los que no la conozcáis, await es un operador de awaitility, muy útil para validación de resultados en procesos asíncronos.

I'm using fastexcel to create the excel file, and I'm flushing it to the OutputStream after every row is written. Right now, I am using a FileOutputStream to write to disk. When the excel file is done being generated, I read it back in using InputStreamResource and stream the response. My thought process is that a ByteArrayOutputStream keeps everything in memory even if I'm flushing the excel file after every row, so I used the FileOutputStream. Does my logic track here? Or am I unnecessarily slowing things down with expensive filesystem IO?

fastexcel the fastest xlsx generation library

I would use some library like for example this one. So you collect all the data you want to store in a list or map, and iterate over it, then add them to the excel like shown in the documentation of the library (should always be the same way more or less for any library)

I've only had memory problems with apache poi. I only use https://github.com/dhatim/fastexcel now