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: 125

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

Article: Building a Global Caching System at Netflix: A Deep Dive to Global Replication

Netflix's EVCache system handles 400M ops/second across 22,000 servers, managing 14.3 PB of data. This infrastructure ensures global availability and resilience through intelligent data routing and flexible replication strategies. By implementing batch compression and switching to DNS-based discovery, Netflix optimizes efficiency, reduces bandwidth usage and significantly lowers operational costs.

By Sriram Rangarajan, Prudhviraj Karumanchi

Podcast: The Ongoing Challenges of DevSecOps Transformation and Improving Developer Experience

In this podcast Shane Hastie, Lead Editor for Culture & Methods, spoke to Adam Kentosh about the ongoing challenges organisations face in their DevOps, DevSecOps and digital transformation journeys.

By Adam Kentosh

Maybe WebAssembly Is the Next Evolutionary Step From Containers: Fermyon at InfoQ DevSummit Munich

During her presentation at the inaugural edition of the InfoQ Dev Summit Munich, Danielle Lancashire, principal software engineer at Fermyon and co-chair of the CNCF wasm-wg, hinted at WebAssembly containers as a greener alternative and a potential evolution from the current containerised approach to serverless computing.

By Olimpiu Pop

NVIDIA Unveils NVLM 1.0: Open-Source Multimodal LLM with Improved Text and Vision Capabilities

NVIDIA unveiled NVLM 1.0, an open-source multimodal large language model (LLM) that performs strongly on both vision-language and text-only tasks. NVLM 1.0 shows improvements in text-based tasks after multimodal training, standing out among current models. The model weights are now available on Hugging Face, with the training code set to be released shortly.

By Robert Krzaczyński

InfoQ Dev Summit Munich: How to Optimize Java for the 1BRC

Java applications passed the 1 Billion Row Challenge (1BRC) in 1.5 seconds. 1BRC creator Gunnar Morling detailed their optimizations at the InfoQ Dev Summit Munich 2024. General optimizations applicable to all Java applications cut the runtime from 290 seconds to 20 seconds. Getting to 1.5 seconds required niche optimizations that most Java applications should forego, except for possibly GraalVM.

By Karsten Silz

© 2024   Created by Michael Levin.   Powered by

Badges  |  Report an Issue  |  Terms of Service