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
Debugging word selection  14 Sep 2019
ViewModel Subscriptions  31 Aug 2019
Redux Subscriptions  25 Aug 2019
Dependency Injection: Views  17 Aug 2019
Dependency Injection: ViewModels  10 Aug 2019
Dependency Injection: Core  27 Jul 2019
Integration Testing  20 Jul 2019
Restructuring Reducers  13 Jul 2019
Vocabulary Browser  29 Jun 2019
Revisiting ViewModelBase  15 Jun 2019
More csharp posts »
Archives
December 2011
2011