Code Smell 64 - Inappropriate Intimacy

Don't get too intimate

25 April, 2023

Contributors

Maxi Contieri

@mcsee

TL;DR: Don't get too intimate

Two classes entangled in love.

Problems

Coupling
Bad Responsibilities Assignments
Bad Cohesion
Class Interfaces too Public
Maintainability
Extensibility

Solutions

Refactor
Merge
Replace Hierarchy With Delegation.

Refactoring

Sample Code

Wrong

class Candidate {

 void printJobAddress(Job job) {

   System.out.println("This is your position address");

   System.out.println(job.address().street());
   System.out.println(job.address().city());
   System.out.println(job.address().zipCode());

   if (job.address().country() == job.country()) {
        System.out.println("It is a local job");
   } 
}

Right

final class Address {
 void print() {
   System.out.println(this.street);
   System.out.println(this.city);
   System.out.println(this.zipCode);   
 } 

 bool isInCounty(Country country) {
  return this.country == country;
}

class Job {
 void printAddress() {

   System.out.println("This is your position address");

   this.address().print());

   if (this.address().isInCountry(this.country()) {
        System.out.println("It is a local job");
   } 
 } 
}

class Candidate {
  void printJobAddress(Job job) {
    job.printAddress();
  }
}

Detection

Some linters graph class relations and protocol dependency. Analyzing the collaboration graph we can infer rules and hints.

Conclusion

If two classes are too related and don't talk much to others we might need to split, merge or refactor them, Classes should know as little about each other as possible.