25 fevereiro 2008

Cockburn e Use Cases



Lendo o blog do Tyner Blain me deparei com post comentando sobre a posição do Alistar Cockburn sobre Casos de Uso e desenvolvimento Ágil.

Entre as principais motivações para utilização de Casos de Uso:

1. The list of goal names provides executives with the shortest summary of what the system will contribute to the business and the users. It also provides a project planning skeleton, to be used to build initial priorities, estimates, team allocation and timing. It is the first part of the completeness question.
2. The main success scenario of each use case provides everyone involved with an agreement as to what the system will basically do, also, sometimes more importantly, what it will not do. It provides the context for each specific line item requirement, a context that is very hard to get anywhere else.
3. The extension conditions of each use case provide the requirements analysts a framework for investigating all the little, niggling things that somehow take up 80% of the development time and budget. It provides a look ahead mechanism, so the customer / product owner / business analyst can spot issues that are likely to take a long time to get answers for. These issues can and should then be put ahead of the schedule, so that the answers can be ready when the development team gets around to working on them. The use case extension conditions are the second part of the completeness question.
4. The use case extension scenario fragments provide answers to the many detailed, often tricky business questions progammers ask: "What are we supposed to do in this case?" (which is normally answered by, "I don't know, I've never thought about that case.") In other words, it is a thinking / documentation framework that matches the if...then...else statement that helps the programmers think through issues. Except it is done at investigation time, not programming time.
5. The full use case set shows that the investigators have throught through every user's needs, every goal they have with respect to the system, and every business variant involved. It is the final part of the completeness question. (And yes, I did indeed sit down and walk through 240 use cases with a client, at the end of which, I turned to her and asked: "And is that everything?" She said, Yes, and we built that, delivered it, got paid for it, and it is still in use ten years later.)


Mas o mais importante desta leitura está a apresentação abaixo. Realmente me fez pensar um pouco sobre a forma que tratamos User Stories, e de que maneira, mudando-se o foco, poderíamos utilizar Casos de Uso para ampliar a visibilidade e o conhecimento de todos da equipe sobre o domínio da aplicação, e mais do que isso, de que maneira esta abordagem se encaixa ao Desenvolvjmento Ágil

Leitura Obrigatória número 4300

Download do Arquivo: Agile Use Cases

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