Patterns

Today I had my fifth live stream. The topic was interfaces , and this time I took a different angle at it: patterns. When I polled about live stream topics you’d like to hear about, most of you said “patterns”. So today’s stream covers several patterns and puts them in perspective of interfaces, or the opposite way around, however you like it.

Today I’ve streamed the Fun with Interfaces video blog at https://www.youtube.com/watch?v=QSMHL32c5mg and the recording is now published online. This was the first session I ever delivered about interfaces, and I actually planned delivering this a lot earlier (I made a suggestion to run this at Directions ASIA before corona crisis hit), but never had a chance.

Whoa! This has been quite an event, the Directions EMEA 2016 in Prague. There has never been this many people (1.700+) and it was quite a pleasure connecting again with old friends, and meeting new friends. Also, it has been quite a pleasure listening to many good sessions, and an even bigger pleasure delivering four of them.

I’ve delved deep into design patterns story with my last two blog posts , but I am far from over. The patterns I discussed are the ones we could use up until NAV 2015 (we can still use them, of course!) but some more robust loose coupling (excuse the near-oxymoron) can be achieved with what NAV 2016 brought along: events.

Achieving some kind of polymorphism in C/AL has always been a problem. The fact that true polymorphism with pure C/AL is outright impossible has not stopped the more stubborn of us to at least give it a try. That’s how some cool patterns emerged.

The purpose of events is to simplify business logic customization while not impeding upgradeability and general extensibility. However, there is one particular class of events that may cause troubles: OnAfter* table events. There are four of them: OnAfterInsert, OnAfterModify, OnAfterDelete, and OnAfterRename.

When I was writing my last post I had a distinct feeling that I was trampling over some boundaries of good NAV design. After all, you should not do stuff like that, NAV isn’t meant to do things like that, or at least that was how I felt. And then two things happened. First, I asked myself: what the heck, why not?

Four months ago I attended a conference, where I had a chance to listen to Miha Kralj, an architect at Microsoft, talk about architectures. It was one of the best presentations I ever attended, and ever since I had this topic in queue, but never really had chance to write about it.