Classes are handy. We can call them and invoke them any time. Is this good?

TL;DR: Don't use your classes as a global point of access.

Problems

• Coupling

• Classes are global unless we use Namespaces.

• Name polluting

• Static Methods

• Static Constants

• Singletons

Solutions

1. Use namespaces, module qualifiers or similar

2. Avoid namespace polluting, keep the Global names as short as possible.

3. Class single Responsibility is to create instances.

Sample Code

Wrong

<?

final class StringUtilHelper {
    static function reformatYYYYDDMMtoYYYYMMDD($date) {
    }
}

class Singleton {

}

final class DatabaseAccessor extends Singleton {

}

Right

<?

namespace Date;

final class DateFormatter {

    function reformatYYYYDDMMtoYYYYMMDD(Date $date) {
    }
    //function is not static since class single responsibility is to create instances and not be a library of utils

}

namespace OracleDatabase;

class DatabaseAccessor {
    //Database is not a singleton and it is namespace scoped
}

Detection

We can use almost any linter or create dependency rules searching for bad class references.

Tags

• Globals

Conclusion

We should restrict our classes to small domains and expose just facades to the outside. This greatly reduces coupling.

Relations

Code Smell 18 — Static Functions

Maxi Contieri ・ Nov 6 '20

#codenewbie #tutorial #development #coding

Code Smell 17 - Global Functions

Maxi Contieri ・ Nov 5 '20

#codenewbie #development #tutorial

More info

Singleton: The Root of all Evil

Maxi Contieri ・ Nov 17 '20

#oop #tutorial #codenewbie #programming

Coupling: The one and only software design problem

Maxi Contieri ・ Feb 6 '21

#webdev #programming #oop #tutorial

Credits

Photo by Alfons Morales on Unsplash

Write shy code — modules that don't reveal anything unnecessary to other modules and that don't rely on other modules' implementations.

Dave Thomas

Software Engineering Great Quotes

Maxi Contieri ・ Dec 28 '20

#codenewbie #programming #quotes #software

This article is part of the CodeSmell Series.

How to Find the Stinky parts of your Code

Maxi Contieri ・ May 21 '21

#codenewbie #tutorial #codequality #beginners