Chapter 8 Iteration 1Elaboration Basics CS 6359 Fall

Chapter 8 Iteration 1—Elaboration Basics CS 6359 Fall 2011 John Cole 1

Requirements and Emphasis • Next. Gen POS system Iteration 1 requirements: – Implement basic Process Sale use case: Entering items and receiving cash payment – Implement a Start Up use case – Do only the “happy path” scenario – No collaboration with external services – No complex pricing rules CS 6359 Fall 2011 John Cole 2

Mailroom Check Processing • Iteration 1: – Start-up use case to authenticate user – Creation of batch with number of checks and total – Entry of checks – Creation of list of checks in batch • Can you see subordinate use cases here? CS 6359 Fall 2011 John Cole 3

Implement Requirements in Phases • All Iteration 1 requirements are subsets • We haven’t even done all the requirements • We don’t even always implement a complete use case in Iteration 1 CS 6359 Fall 2011 John Cole 4

Review: Inception • Short requirements workshop • Most actors, goals, and use cases named • Most use cases in brief format, and 10 -20% in full dress • Most influential and risky requirements identified • Version 1 of vision and Supplementary Specification written CS 6359 Fall 2011 John Cole 5

Review: Inception • • Risk list Proof of concept prototypes User interface prototypes Recommend on buy/build High-level candidate architecture Plan for first iteration Possible tools CS 6359 Fall 2011 John Cole 6

Elaboration • Two or more short (2 -6 week) iterations. Shorter is better. • This is not a design phase • Produce production-quality code CS 6359 Fall 2011 John Cole 7

Elaboration Tasks • Core, risky software architecture programmed and tested • Majority of requirements discovered and stabilized • Major risks mitigated or retired • Estimate overall schedule and resources • Test early and often • Adapt based on user feedback CS 6359 Fall 2011 John Cole 8

Start These in Elaboration • • • Domain model Design model Software architecture document Data model Use-case storyboard User interface prototypes CS 6359 Fall 2011 John Cole 9

You Didn’t Understand Elaboration • • More than a few months long It has only one iteration Most requirements defined before elaboration Risks are not being tackled No executable code Considered a requirements or design phase Full, careful design No early testing CS 6359 Fall 2011 John Cole 10

Planning the next Iteration • Use these criteria to rank requirements: • Risk includes technical complexity as well as uncertainty of effort or usability • Coverage implies that all major parts of the system are known in early iterations • Criticality is functions the client considers of high business value CS 6359 Fall 2011 John Cole 11