Code Smell 143 — Data Clumps
Some objects are always together. Why don’t we split them?
Published in
2 min readJun 23, 2022
TL;DR: Make cohesive primitive objects travel together
Problems
- Bad Cohesion
- Duplicated Code
- Validation Complexity
- Readability
- Maintainability
Solutions
- Extract Class
- Find small objects
Context
This smell is friends with primitive obsession.
If two or more primitive objects are glued together, with business logic repeated and rules between them, we need to find the existing concept on the bijection.
Sample Code
Wrong
public class DinnerTable
{
public DinnerTable(Person guest, DateTime from, DateTime to)
{
Guest = guest;
From = from;
To = to;
}
private Person Guest;
private DateTime From;
private DateTime To;
}Right
public class TimeInterval
{
public TimeInterval(DateTime from, DateTime tol)
{
// We shoud validate From < To
From = from;
To = to;
}
}public DinnerTable(Person guest, DateTime from, DateTime to)
{
Guest = guest;
Interval = new TimeInterval(from, to);
}
Detection
[X] Semi-Automatic
Detection based on cohesion patterns is available o a few linters.
Tags
- Cohesion
Conclusion
Group behavior in the right place and hid the primitive data.
Relations
More Info
Credits
Photo by Dynamic Wang on Unsplash
The heart of the software is its ability to solve domain-related problems for its user. All other features, vital though they may be, support this basic purpose.
Eric Evans
This article is part of the CodeSmell Series.
