Category: Development

Lets start with create/update/delete using good old fashioned WebMvc Spring, Kotlin and JOOQ.

Following checkpoint has:

• Gradle kts build script
• JOOQ code generation from DB
• SQL script to initialize DB
• Controllers and repositories to create/update/delete many entities.
• Some basic error handling
• Some extension functions.
• Open API auto-generated

https://github.com/MavoCz/myhome/tree/checkpoint-01-crud

Notes:

To set up logging of JOOQ queries:

Which gives you awesome insight into every SQL query and result:

Code generation of JOOQ works well, but its a bit hard to set up. The configuration below scans a database and creates JOOQ table definitions and records.

It can automatically map Kotlin/Java enums for you, but each needs to be configured. See lines 27.

Kotlin gotcha: For some reason injection into super class did not work without open keyword for every property.

Some notes to DB update code:

Don’t forget to call execute at the end. updatedRecord is R : Record, where record is org.jooq.Record. Idea keeps importing java.lang.Record which is quite annoying. updatedRecord creates a minimal set or changes, so if it contains only one changed field, it will have only one field in final SQL. Nice.

Jooq Records are a nice way to hold/manipulate/transfer DB data to insert/update/result.

It can be mapped nicely to and from a DTO/data class, generator is able to create on per entity record class with convenience methods named after columns. And if you don’t want to deal with those pesky DTOs, it can serialize data to JSON too.

Since its that time of the year again and holiday spirit is once again elevated by advent of code challenge, I decided to participate, but this time with the help of Github AI assistant Copilot.

So start 2 month trial, install Idea plugin and here we go. And the first impressions were … not great. At first it did not generate anything. I spent 10 minutes with trying few things. Then I found out how to define method and first sudgestions appeared.

It seemed like it was reading my mind … code was sometimes usable as is, sometimes needed a bit of tweaking, rarely was completely off. But I was amazed about how it worked out

I had to implement a library which evaluates a set of mathematical expressions with variables, where each variable can also be an expression. Luckily we had JGraphT library already on the class path, so it was quite quick and painless. All that is needed is:

• Parse all expressions, extract variables
• Build a directed graph, expression is a node and edge represents a dependency of an expression on other expression/variable.
• Check that it does not contain cycle.
• Create a DepthFirstIterator and gradually calculate all expression values and collect them in a map. This ensures that all variable values are available when an expression is evaluated.

Code can be found here:

https://github.com/MavoCz/GraphExpressionEvaluator

Example of an expression tree as created by JGraphT visualisation:

I participated in Advent of Code challenge this year (2021). For those unfamiliar with this its a series of 25 coding challenges, each released on next day from 1st to 25th of December. For completing each you get a star and bragging rights in front of your colleagues :).

https://adventofcode.com/2021/about

For those who like moving pictures, there is a Youtube video from the creator and maintainer of Advent of Code. Quite funny.

I implemented 20 and half days in Kotlin language to brush up on my Kotlin skills. Learned a lot and quite a lot of fun, but in the end I got burned out and did not finish the last 4 and half days.

https://github.com/MavoCz/advent-of-code

I started to like Kotlin :heart:

I had to switch to Mac from Windows for my current job. Its a reasonably painful transition so far :). This post is to be used as memory dump to help me (and perhaps others) with the transition.

First observation is that Intel Mac has the same fan problems as windows laptop :). Got the 16 inch Mac Pro with I9 and the fans are loud even with medium load.

Second is that the Dell thunderbolt dock does not work with Mac. Oh well.

Install git

which is part of xcode for some reason and installation takes for ever

xcode-select --install
git config --global user.name "<your name>"
git config --global user.email "<your email>"

Copy your ssh key to ~/.ssh (or create a new one).

Brew

Install brew as described on https://brew.sh

Terminal

Make it pretty with oh my zsh:

sh -c "$(curl -fsSL https://raw.githubusercontent.com/ohmyzsh/ohmyzsh/master/tools/install.sh)"

And install ITerm2.

Install Java

Use SDKMAN as described here: https://stackoverflow.com/questions/52524112/how-do-i-install-java-on-mac-osx-allowing-version-switching

Java will be installed here: /Users/USER/.sdkman/candidates/java/current

Install Postgresql

brew install postgresql
createuser -s postgres
brew services restart postgresql

Windows app replacement

Install Commander One as Total Commander replacement through Apple store.

Install Rectangle for better window management similar to PowerTools.

Install MonitorControl so you can actually control brightness of an external display :facepalm:

https://github.com/MonitorControl/MonitorControl

Useful shortcuts

Shortcuts on Macbook pro are quite a bit more complex. Instead of two switch buttons Alt+Ctrl on Win, you have Ctrl+Option+Command on Mac. Additionally on Mac with touch bar (my case) you must press fn quite a lot. In Idea the combinations of switches does not make much sense … or I did not yet figure out the various permutations of keys.

Command + Control + Shift + 4 – capture screen to clipboard

Command + ~ – Switch between windows of same app. For example two chrome browsers with different accounts.

Option + left/right – move to Next/previous word

Command + Q – quit

Command + Controll + Q – lock the computer

Command + Option + Escape – Force Quit is hidden in the Apple menu in the top left-hand corner of your screen.

Disable unneeded shortcuts in System preferences / Keyboard / Shortsuts as they are clashing with Intellij Idea.

Reactor 3.1.0 added a brand new and shiny operator expand, which solved by long term dilemma about how to implement downloading of paginated REST endpoints without recursion.