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A feature
is a small, client-valued function expressed in the form
<action><result><object>. As the name implies, features
are an important aspect of
Feature-Driven Development (FDD)
(Palmer
and Felsing 2002). Figure 1
shows several features for the university system.
Features are very small and typically can be implemented
within a few hours. |
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Figure 1. Features.
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Add a student to a seminar
waiting list.
-
Calculate fee for a parking
pass.
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Calculate the average mark on
a transcript.
-
Display the name and address
of a student on a transcript.
-
Drop a student from a
seminar.
-
Enroll a student in a
seminar.
-
List the prerequisites for a
seminar.
-
List the seminars of a
student on a transcript.
-
Track number of parking
passes.
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The features in
Figure 1 are basically a formalized version, wording
wise at least, of traditional features. Another
formalized approach is to write features as shall
statements. For example “calculate the average mark on
a transcript” would be worded “The system shall
calculate the average mark on a transcript”. Although
the wording changes slightly in the end features and
shall statements are effectively the same thing in my
experience.
Although one of the primary
advantages of features is that their small size makes
them easy to estimate and to implement their size also
poses a problem in that one feature by itself rarely
provides significant value to stakeholders. The
solution is to organize features into groups called
“feature sets”. Figure 2
depicts how the features of Figure 1
would be organized into three feature sets –
Transcript, Enrollment, and Parking Passes.
As you can see each feature set contains two or more
related features.
Figure 2. Feature sets.
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Transcript
-
Calculate the average mark on
a transcript.
-
List
the seminars of a student on a transcript.
-
Display
the name and address of a student on a transcript.
Enrollment
-
List the prerequisites for a
seminar.
-
Enroll a student in a
seminar.
-
Drop a student from a
seminar.
-
Add at student to a seminar
waiting list.
Parking Passes
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From a requirements point of view features
are to FDD as
use cases are to the
Rational Unified Process (RUP) and
user stories are to XP – they’re a primary source of
requirements and the primary input into your planning
efforts. However, from a size point of view
feature sets are much closer conceptually to use cases.
Features are estimated and
prioritized in a similar manner to user stories.
Because features are so simple to create it is common to
use very simple tools – such as index cards or a
spreadsheet – to capture them.
This artifact description is excerpted from Chapter 7 of
The Object Primer 3rd Edition: Agile Model Driven
Development with UML 2.
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The Object Primer 3rd Edition: Agile Model Driven
Development with UML 2 is an
important reference book for agile modelers,
describing how to develop 35
types of agile
models including all 13
UML 2 diagrams.
Furthermore, this book describes the techniques
of the
Full Lifecycle Object Oriented Testing
(FLOOT) methodology to give you the fundamental
testing skills which you require to succeed at
agile software development. The book also
shows how to move from your agile models to
source code (Java examples are provided) as well
as how to succeed at implementation techniques
such as
refactoring and
test-driven development
(TDD). The Object Primer also includes a
chapter overviewing the critical database
development techniques (database refactoring,
object/relational mapping,
legacy analysis, and
database access coding) from my award-winning
Agile Database Techniques
book. |
 |
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Agile Modeling: Effective Practices for Extreme
Programming and the Unified Process is the seminal
book describing how agile software developers approach
modeling and
documentation. It describes principles and
practices which you can tailor into your existing
software process, such as
XP, the
Rational Unified Process (RUP), or the
Agile Unified Process (AUP), to streamline your
modeling and documentation efforts. Modeling and
documentation are important aspects of any software
project, including agile projects, and this book
describes in detail how to
elicit requirements,
architect, and then
design your system in an agile manner. |
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The Elements of UML 2.0 Style describes a collection
of standards, conventions, and
guidelines
for creating effective
UML diagrams. They are based on sound, proven
software engineering principles that lead to diagrams
that are easier to understand and work with. These
conventions exist as a collection of simple, concise
guidelines that if applied consistently, represent an
important first step in increasing your productivity as
a modeler. This book is oriented towards
intermediate to advanced UML modelers, although there
are numerous examples throughout the book it would not
be a good way to learn the UML (instead, consider
The Object Primer). The book is a brief 188
pages long and is conveniently pocket-sized so it's easy
to carry around. |
Translations
I actively work with clients around the world to
improve their information technology (IT) practices as
both a mentor/coach and trainer. A full
description of what I do, and how to contact me, can be
found here.
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