The “Reinventing the Wheel” Anti-Pattern

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Reinventing the Wheel As a moderator on the JavaRanch, I often come across posts asking how to reinvent features that are available in most application servers. In JDBC for example, I’ve had people ask how to implement their own database connection pooling and how to create their own JDBC driver. Often times the developer is trying to create something that already exists, but they are unsure how to use it. The general rule of thumb I tell programmers is, “If you feel like you are reinventing the wheel, you probably are”.

Review the API
If you ever get the feeling you are inventing the wheel, it’s a pretty good indication you are. In such situations, ask yourself “Is it likely a developer using the same component would need functionality X?”. If the answer is “yes”, then there’s a good chance there’s already such a feature in the API. Most often, reinventing the wheel comes from developers who are too lazy to review the API but not lazy enough not to rewrite the feature they think they are missing. Also, search the web. In some cases, you may need to download a new or updated library to get the feature you want, but this may give you access to even more features.

Your wheel isn’t better
Often called “Reinventing the square wheel”, it is likely the code you are recreating is worse, more buggy, and far less stable than the code you should be using. If you consider it for a moment, it makes sense a method built within the API should be better than a method built on top of the API. The API developer has access to private methods and objects that you do not have access to, and therefore your solution is limited by the public/external methods of the API. Furthermore, the fact the code is part of the API means scores of developers have hopefully reviewed the code for errors and performance enhancements.

That doesn’t necessarily mean the API implementation is better, but whenever I hear a developer say “I have a faster and cooler way of doing this than the way they do it in library” I cringe at the thought of what they may have written. If you do happen to create a better wheel, join the open source project and publish it for others to judge.

There’s always public humiliation
Many of the worst best articles that appear on the The Daily WTF come from programmers reimplementing the most basic functions of a language. One of the things that separates an experienced programmer from a beginner is the ability to recognize what tools in the API are needed for a task and how quickly they can be put together. And with that, I present a list of examples written by real developers and posted online for the world to see:

Any my personal favorite: I’ve heard from some good sources that the next version of SQL will use the word “GIMMIE” instead of “SELECT”

benefits of twitter lists

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I really like twitter lists.  JobMob blogged about how to use them.  I agree with what they said, but have a different personal use for them.  Here’s my take on twitter lists.

I use twitter in several different ways.  Lists help me deal with those ways.

Current tweets

This is the traditional see things as it happens model that twitter was founded on.  I don’t read everything this way, but it is good for seeing a small number of the most recent tweets.

Before lists: I used TwitterFox now EchoFon to see tweets that come when I happen to be online.

After lists: Same.

Reading a lot of tweets

I get home after work and am curious what kinds of things have been tweeted that day.  This is where lists shine.  Even if you were reading the same number of tweets, it is faster to read them in logical groups rather than time.  And lists let you skip ones you don’t feel like reading.

Before lists: Follow less people so they wouldn’t clog up my tweet stream.  Use an RSS feed for some topics so they wouldn’t clog up my tweet stream but I could still read them.

After lists:

One time setup

  • Follow the people I was following by RSS so now I’m following everyone I want to
  • Add *all* my contacts to one list.  Some public lists and some private lists
  • Open all my lists in Firefox tabs and bookmark the set

To read

  • Open all tabs in Firefox.
  • Look at the ones I am interested in.  (for example, read jokes tab when I need a pick me up)

Reading tweets on a topic

Before lists: Scan tweet stream, search

After lists: Open the list pertaining to the topic.  Easy!

Public vs Private Lists

Public lists are good for things like

  • listing the JavaRanch moderators
  • jokes
  • topics of interest.

Private lists are good for things like:

  • hobbies you prefer to keep quiet
  • more sensitive topics (like the society of secret _____)
  • less than complementary lists (I have a “people-who-post-way-too-much” list for people who I am interested in periodically, but don’t want to read all their stuff)
  • “other” – a kitchen sink list until there are more people in that category – it doesn’t really make sense to others

Conclusion

Lists may not have been out long, but I rely on them already.  Combined with tab bookmarking, they are very powerful.  I imagine this twitter clients will catch up soon.

Follow me on twitter @jeanneboyarsky

http://twitterfox.net/

normalization done poorly at the bank

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I went to a bank yesterday to inquire why I was receiving mail at my old address despite having moved a number of months ago.  The first thing the representative did was pull up my record to show me that my address was correct in their system.  While that’s very nice, the mail has their name on it.  What’s more, I have received mail from this bank at my correct address already.

Then the representative tells me he’ll try to change it again in case the other person didn’t do it right.  While doing this he finds the problem and shows it to me.  This bank, in all their wisdom, has the customer’s mailing address on two screens.  A representative must make the change in two places.

Lessons from this:

  1. Scott blogged about normalization last year.  Having information in two places invites one to be wrong.  And we aren’t talking about the name of the state here.  Customer address is a piece of information you would expect to change over time.
  2. If you do have the same data in two places, you should write code that updates both rather than require people to do it.