Photo by Ade Adebowale on Unsplash
Code Smell 131 - Zero Argument Constructor
Objects created without arguments are often mutable and erratic
TL;DR: Pass all your essential arguments when creating objects.
Problems
Anemic Models
Solutions
Context
It is common usage using a zero-argument constructor and a bunch of setters to change it.
Beans is a well-known example of this code smell.
Sample Code
Wrong
public Person();
// Anemic and mutable
Right
public Person(String name, int age){
this.name = name;
this.age = age;
}
}
// We 'pass' the essence to the object
// So it does not mutate
Detection
[X] Automatic
We can check all constructors, but there are some false positives.
Stateless objects are a valid example.
Tags
- Mutability
Conclusion
Empty constructors are mutability hints and accidental implementation issues.
We need to research usages to improve our solutions.
Relations
More Info
Credits
Photo by Ade Adebowale on Unsplash
Don't worry about design, if you listen to your code a good design will appear...Listen to the technical people. If they are complaining about the difficulty of making changes, then take such complaints seriously and give them time to fix things.
Martin Fowler
This article is part of the CodeSmell Series.