While investigating a routine bug fix today, I came across some code that can only be described as a buried cry for help …

public void Adjust(
    DateTime? open, DateTime? due, DateTime? close)
{
    if (!open.HasValue)
        throw new ArgumentNullException("open");
    if (!due.HasValue)
        throw new ArgumentNullException("due");
    if (!close.HasValue)
        throw new ArgumentNullException("close");
    // ...
}

Why would a developer declare parameters as nullable DateTimes and then immediately write guard clauses to prevent nulls from being accepted.

If you don’t want to support nulls, use a regular date time.

There are two lessons to learn here, one specific and one general.

The specific lesson: Use the right type for each parameter - use the most liberal type that makes sense (for example, use IEnumerable<T> instead of IList<T> unless you need indexed access), but no more liberal (don’t use DateTime? unless you’re willing to accept nulls).

The general lesson: Don’t make code more complex than it needs to be - do things the simplest way that makes sense. Being a developer is hard enough, we shouldn’t go out of our way to make it harder.

Comments

blog comments powered by Disqus
Next Post
Looking forward to 2012  31 Dec 2011
Prior Post
A story about Magic  10 Dec 2011
Related Posts
Caching without Race Conditions  13 Jun 2020
Improved Caching  09 May 2020
Caching Speech  25 Apr 2020
Speech Middleware  11 Apr 2020
Redux Middleware Implementation  28 Mar 2020
Redux Middleware  14 Mar 2020
Always review code you copy  29 Feb 2020
Speech API  15 Feb 2020
Logging Implementation  25 Jan 2020
Logging Demonstrated  11 Jan 2020
More csharp posts »
Archives
December 2011
2011