The monk Djishin had grown dispirited from toiling on obscure
projects for the One Shoe Clan, far removed from the bustle of
temple life. He appealed to master Banzen for more meaningful
work.
Said Banzen, “I can think of one application whose codebase has
grown confused over the years, owing to its many owners. I
suspect it hides much rubbish which may be cleared away.”
When Banzen examined Djishin’s refactoring he found the code to
be well-organized and greatly simplified. The most dramatic
reduction had been in the number of Data Transfer Object classes.
“I retained only those classes which map directly to database
tables,” Djishin explained proudly. “See, here is a query
which joins the Campaign, Soldier, and Specialty tables, fetching
but two columns from each. Previously there was a DTO whose only
purpose was to return the six values for each row—shameful! Now
the query returns a list of Campaign instances, each holding a
list of Soldiers, each in turn holding a list of Specialties.
True, the presentation layer must now traverse these objects, but
they are common throughout the application and will be familiar
to all who labor upon it.”
Banzen stroked his beard. “You have adopted the ways of the
Object-Relational Mapping, in a framework of your own devising. I
am acquainted with the virtues of this approach, but also with
its vices. These three tables have about twenty columns each; the
domain objects which mirror them have likewise twenty fields. So
now instead of fetching six columns per row, are you fetching
sixty? Or executing the query in three passes? Or employing some
sort of cache?”
“None of these,” said Djishin with satisfaction. “I fetch
only the original six columns, plus primary keys. All other
fields in the domain objects are simply left uninitialized.”
Banzen sighed and reached for his staff.
Djishin awoke outside with a pounding headache, covered by a
blanket of new-fallen snow. He was alone in the middle of a tidy,
perfectly level field surrounded by great pines. All gleamed
white in the morning sun, and a few flurries were still spinning
through the air.
At his feet a long stick had been thrust into the ground. A note
was tied around the middle. Djishin unrolled it.
I ordered the One Shoe Clan to remove all the refuse from the
temple’s rubbish yard. Is it not lovely now?
Sadly, this left behind many deep pits that would require too
much effort to fill, so we covered the tops quite artfully with
the thinnest layer of branches and leaves. Since a good snow has
been forecast for this evening, I expect you will awaken to a
picture of perfection.
