Class Family Accord - Abstract

 

An Accord class family is a hierarchy of classes for which another class hierarchy has been designated as corresponding. Class  A0 is the top of the class family, class A1 extends A0, class An extends An-1.

The partner of this class family is B0 at the top, Bn extends Bn-1. Class family A and B are have an Accord relationship if, by design intention, An corresponds to Bn. In each level, there is at least one method that overrides or defines a variant with a behavior representative of the progression of requirements.

The intention of this design concept is to maintain this correspondence when, as requirements evolve, the design calls for extending An and Bn into An+1 and Bn+1. The reason for maintaining this relationship would be that A has new or refined behaviors that only make sense with reference to the state or behaviors of B at the same level.

 

To realize this relationship in the Java programming language, a designer could simply document the intention. However, coding would inevitably require explicit down cast to force references to the intended levels. This white paper suggests a set of Java annotations to make the Accord relationship between class families explicit and generate the necessary dispatch code and casts. The resulting generated code would in effect provide a parametric override capability.

 

At a minimum an annotation @Accord  designates a class as the head or subclass in a class family. Its attribute has an attribute, partner, to identify the other class family. Methods that are intended to follow the progression are annotated as @Covariant. The effect is to make the method be a covariant override. Its parameter referring to a class at the same inheritance level in the partner family is treated a covariant. A prototype precompiler is (to be) provided for research purposes.

Views: 131

Comment

You need to be a member of Codetown to add comments!

Join Codetown

Happy 10th year, JCertif!

Notes

Welcome to Codetown!

Codetown is a social network. It's got blogs, forums, groups, personal pages and more! You might think of Codetown as a funky camper van with lots of compartments for your stuff and a great multimedia system, too! Best of all, Codetown has room for all of your friends.

When you create a profile for yourself you get a personal page automatically. That's where you can be creative and do your own thing. People who want to get to know you will click on your name or picture and…
Continue

Created by Michael Levin Dec 18, 2008 at 6:56pm. Last updated by Michael Levin May 4, 2018.

Looking for Jobs or Staff?

Check out the Codetown Jobs group.

 

Enjoy the site? Support Codetown with your donation.



InfoQ Reading List

Sixteen Claude Agents Built a C Compiler Without Human Intervention... Almost

In an effort to probe the limits of autonomous software development Anthropic used sixteen Claude Opus 4.6 AI agents to build a Rust-based C compiler from scratch. Working in parallel on a shared repository, the agents coordinated their changes and ultimately produced a compiler capable of building the Linux 6.9 kernel across x86, ARM, and RISC-V, as well as many other open-source projects.

By Sergio De Simone

From Paging to Postmortem: Google Cloud SREs on Using Gemini CLI for Outage Response

A recent article by Google Cloud SREs describes how they use the AI-powered Gemini CLI internally to resolve real-world outages. This approach improves reliability in critical infrastructure operations and reduces incident response time by integrating intelligent reasoning directly into the terminal-based operational tools.

By Renato Losio

Firestore Adds Pipeline Operations with Over 100 New Query Features

Google has overhauled Firestore’s query engine, introducing "Pipeline operations" that enable complex server-side aggregations and array unnesting. The update shifts Firestore Enterprise toward an optional indexing model, allowing architects to prioritize write speed and lower costs. While it brings parity with MongoDB-style aggregations, the preview currently lacks real-time and emulator support.

By Steef-Jan Wiggers

Nuxt Studio Released: Open Source CMS for Content Editing in Production

Introducing Nuxt Studio: the ultimate open-source content management solution for Nuxt websites, offering a powerful self-hosted module for complete control over your content. With an intuitive visual editor, real-time previews, and seamless Git integration, elevate your development workflow while bridging the gap for content creators. Unleash your team's potential today!

By Daniel Curtis

Presentation: Building Embedding Models for Large-Scale Real-World Applications

Sahil Dua discusses the critical role of embedding models in powering search and RAG applications at scale. He explains the transformer-based architecture, contrastive learning techniques, and the process of distilling large language models into production-ready student models. He shares insights on optimizing query latency, handling document indexing, and evaluating retrieval quality.

By Sahil Dua

© 2026   Created by Michael Levin.   Powered by

Badges  |  Report an Issue  |  Terms of Service