Object Mentor Blog: Marick's Law

Marick's Law

Uncle Bob — Sat, 29 Nov 2008 14:12:00 -0600

A month ago I was deep in the throes of shipping the current release of FitNesse. I just wanted to get it done. I was close to delivery when I spotted a subtle flaw. To fix this flaw I decided to insert identical if statements into each of 9 implementations of an abstract function.

My green wrist band was glowing a nasty shade of puke. I knew I was duplicating code. I knew that I should use the Template Method pattern. But that just seemed too hard. I was convinced that it would be faster to spew the duplicated code out into the derivatives, get the release done, and then clean it up later.

So this morning I was doing something else, and I spotted this duplicated code. I sighed, as I looked down at my green wrist band, and thought to myself that I’d better eat my own dog food and clean this mess up before it gets any worse. I was dreading it.

I made sure that every occurrence of the statement was identical. Then I went to the base class with the intention of refactoring a Template Method. When, what to my wondering eyes should appear, but a Template Method that was already there.

I sheepishly copied and pasted the if statement from one of the derivatives into the Template Method, and then deleted the other eight instances.

I ran the tests.

They all passed.

Damn.

My green wrist band is shouting: “I TOLD YOU SO!”

For my penance I did 20 recitations of Marick’s law. “When it comes to code it never pays to rush.”

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"Marick's Law" by worker compensation lawyers

Tue, 24 Nov 2009 13:17:27 -0600

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"Marick's Law" by family lawyers sydney

Thu, 12 Nov 2009 12:28:18 -0600

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"Marick's Law" by ed hardy

Mon, 28 Sep 2009 10:33:55 -0500

So much harder to slack off with others watching …..

"Marick's Law" by DinnerwarE

Fri, 11 Sep 2009 12:41:36 -0500

Oh i agree on that, rushing code always puts us in trouble! But i did not know about these green wrist band and i just love them, i’ll send a donation and will get a few for the office, it’s a funny reminder that can really get helpfull!

"Marick's Law" by Bret Pettichord

Fri, 06 Mar 2009 14:59:49 -0600

And a raspberry when it sees us doing too much cut n paste.

"Marick's Law" by Mike Finney

Sat, 29 Nov 2008 15:57:26 -0600

Hmmm. Perhaps we should make a plug-in for our IDE which has a little character applauding when it recognizes a refactoring we did. :) Perhaps a nice sound. (Ding!)

"Marick's Law" by llewellyn falco

Sat, 29 Nov 2008 15:31:59 -0600

I agree with this, but I have to say that pairing makes it easier to implement. So much harder to slack off with others watching