Skip to main content

Akka Java API and traits

Switching to English...

Using the Java API with Akka might result in somewhat ugly code, especially if using the UntypedActor classes. If an actor has many types of messages it can receive, it may result in long "if instanceof" chains. The situation can be improved by using AbstractActors or even TypedActors in some cases.

There might be an alternative though. To make the code a bit prettier, one solution can be to loan the idea of traits from Scala. Java interfaces with default methods can be used to achieve similar behavior.

Let's say we have an Actor A with some messages [B, C, D] it expects. Instead of writing a long handleMessage method with all kinds of if statements, we can set the A to implement interface CTrait. The CTrait has a default method handleC which then handles the C typed message. The CTrait may also force the A to expose some methods so it can do it's job. Finally we need such a setup that handleC is called from A, preferably without writing any code in A. In abstract actor case, we could use the ReceiveBuilder so when A is created, we add the CTrait method there. Alternatively we could annotate the CTrait handleC (@Handle(C.class)?) and use reflection to call the handleC from somewhere (A?) without knowing what handleC is.

These are a bit hacky solutions (to be honest, i have yet to figure out an elegant way). The usefulness of these kinds of traits is a bit questionable. The few benefits include that we don't need any "if instanceof [B,C,D]". Also one or more traits can be plugged in to any actor and we can avoid inheritance (A extends CHandlingActor) which will result to trouble. CTrait has not state so it can't mess with A unknowingly.

Comments

Popular posts from this blog

I'm not a passionate developer

A family friend of mine is an airlane pilot. A dream job for most, right? As a child, I certainly thought so. Now that I can have grown-up talks with him, I have discovered a more accurate description of his profession. He says that the truth about the job is that it is boring. To me, that is not that surprising. Airplanes are cool and all, but when you are in the middle of the Atlantic sitting next to the colleague you have been talking to past five years, how stimulating can that be? When he says the job is boring, it is not a bad kind of boring. It is a very specific boring. The "boring" you would want as a passenger. Uneventful.  Yet, he loves his job. According to him, an experienced pilot is most pleased when each and every tiny thing in the flight plan - goes according to plan. Passengers in the cabin of an expert pilot sit in the comfort of not even noticing who is flying. As someone employed in a field where being boring is not exactly in high demand, this sounds pro...

PydanticAI + evals + LiteLLM pipeline

I gave a tech talk at a Python meetup titled "Overengineering an LLM pipeline". It's based on my experiences of building production-grade stuff with LLMs I'm not sure how overengineered it actually turned out. Experimental would be a better term as it is using PydanticAI graphs library, which is in its very early stages as of writing this, although arguably already better than some of the pipeline libraries. Anyway, here is a link to it. It is a CLI poker app where you play one hand against an LLM. The LLM (theoretically) gets better with a self-correcting mechanism based on the evaluation score from another LLM. It uses the annotated past games as an additional context to potentially improve its decision-making. https://github.com/juho-y/archipylago-poker

"You are a friendly breadwinner"

A recent blog post by Pete Koomen about how we still lack truly "AI-native" software got me thinking about the kinds of applications I’d like to see. As the blog post says, AI should handle the boring stuff and leave the interesting parts for me. I listed down a few tasks I've dealt with recently and wrote some system prompts for potential agentic AIs: Check that the GDPR subprocessor list is up to date. Also, ensure we have a signed data processing agreement in place with the necessary vendors. Write a summary of what you did and highlight any oddities or potentially outdated vendors. Review our product’s public-facing API. Ensure the domain objects are named consistently. Here's a link to our documentation describing the domain. Conduct a SOC 2 audit of our system and write a report with your findings. Send the report to Slack. Once you get approval, start implementing the necessary changes. These could include HR-related updates, changes to cloud infras...