Speaking at Boulder Java User Group, 9 February 2010

Jan 27, 2010 | George Fairbanks

I will be presenting a lecture on Design
at the
Boulder Java User Group meeting on 9
February 2010 at 6pm (before the pizza break). The lecture will be
based on my thesis work. You can find a preview slide presentation on
the work
More details, including the full thesis, are available

You can watch a video of this talk, given at CU

Example design fragment

The following picture shows a UML static structure diagram of a design
fragment. It shows the framework classes involved with creating an
Eclipse context menu (right-click menu) and the classes that a
developer must implement. The complete DF would also include
behavioral specifications. (Apologies for the cropped text in the SVG

Talk abstract ————-

Frameworks are a valuable way to share designs and implementations on
a large scale. Client programmers, however, have difficulty using
frameworks. They find it difficult to understand non-local
client-framework interactions, design solutions when they do not own
the architectural skeleton, gain confidence that they have engaged
with the framework correctly, represent their successful engagement
with the framework in a way that can be shared with others, ensure
their design intent is expressed in their source code, and connect
with external files.

A design fragment is a specification of how a client program can use
framework resources to accomplish a goal. From the framework, it
identifies the minimal set of classes, interfaces, and methods that
should be employed. For the client program, it specifies the
client-framework interactions that must be implemented. The structure
of the client program is specified as roles, where the roles can be
filled by an actual client s classes, fields, and methods. A design
fragment exists separately from client programs, and can be bound to
the client program via annotations in their source code. These
annotations express design intent; specifically, that it is the
intention of the client programs to interact with the framework as
specified by the design fragment.

We can provide pragmatic help for programmers to use frameworks by
providing a form of specification, called a design fragment, to
describe how a client program can correctly employ a framework and by
providing tools to assure conformance between the client program and
the design fragments.

I built tools into the Eclipse IDE to demonstrate how design fragments
could alleviate the difficulties experienced by client programmers. I
performed two case studies on commercial Java frameworks, using demo
client programs from the framework authors, and client programs I
found on the internet. The first case study, on the Applet framework,
yielded a complete catalog of twelve design fragments based on our
analysis of fifty-six Applets. The second case study, on the larger
Eclipse framework, yielded a partial catalog of fourteen design
fragments based on our analysis of more than fifty client programs.

This work provides three primary contributions to software engineering:

  1. It provides a new technique to help programmers use frameworks.
  2. It provides a systematic way to increase code quality. Design fragments provide a means to communicate known-good designs to programmers, and, unlike simple copying of examples, a means of influencing the uses of that design so that revisions can be propagated.
  3. It provides an empirically-based understanding of how clients use frameworks, which aids researchers in choosing research directions and aids framework authors in delivery of new frameworks.


George Fairbanks is a software developer, designer, and architect living in New York city


+1-303-834-7760 (Recruiters: Please do not call)
Twitter: @GHFairbanks