Jenny Harlow

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Project

Designing a simple collections framework

Introduction

In COSC324 Wal emphasised the use of Collections for efficient programming. He pointed out some of the ways in which the Java Collections Framework uses design patterns (wrappers, iterators, factory methods), but also some of the glaring Arrghghgs (the OO term seems to be antipatterns) that there seem to be in the current design. Naturally we all nodded wisely and agreed that it is just terrible ... It's easy to criticise, but just how easy is it to design a collections suite?

This project will attempt to redesign part of the Java Collections Framework from the point of view of 'if we were starting again, what might we do'. The whole framework is huge, and includes many specialised features such as the java.util.concurrent classes. This project will focus on what we might consider to be the main everyday-usage collections - the ones that come into almost everything we might want to write: lists, sets, maps.

Design study

Aims

My aim is to create a design for a collections framework that includes lists, sets and maps and provides equivalent functionality to the existing implementations.

Design issues

My initial thinking about this project made me realise that a major issue for Collections is contracts: Collections are for other programmers to use and so using and abiding by design by contract has to be just as important, if not more so, as conspicuous display of GoF-authorised design patterns. Am I claiming the design by contract is more important here than in some of the other projects? No, but I am saying that it is very very relevant when designing a framework whose sole purpose is to provide objects to be used by clients.

all things to all men

Optional extras

If I have time I am interested in the idea of a performance test suite for collections, running some standard tests and providing a summary of results.

Design Critique

Design Improvements

I have set up a separate page design scratch-pad for thoughts-in-progress that are too open-ended to have made it here yet.