Incomplete objects cause lots of issues.

Problems

• Mutability
• Incomplete objects
• Concurrency inconsistencies between creation and essence setting.
• Setters

Solutions

• Pass the object’s essence on creation

Examples

• Some persistence frameworks in static typed languages require an empty constructor.

Exceptions

• Stateless objects. Always better solution than static class methods.

Sample Code

Wrong

Right

Detection

Any linter can warn this (possible) situation.

Tags

• Essence
• Incomplete
• Mutable

Conclusion

Always create complete objects. Make their essence immutable to endure through time. Every object needs its essence to be a valid one since inception.

Writing a class without its contract would be similar to producing an engineering component (electrical circuit, VLSI (Very Large Scale Integration)…

In this serie we will see several symptoms and situations that make us doubt the quality of our developments.

We will present possible solutions.

Most of these smells are just clues of something that might be wrong. They are not rigid rules.

Code Smells

Protocol is empty (with setters/getters).

If we ask a domain expert to describe an entity he/she would hardly tell it is ‘a bunch of attributes’.

Problems

• No Encapsulation.
• No mapping to real world entities.
• Duplicate Code
• Coupling

Solutions

1) Find Responsibilities.

2) Protect your attributes.

3) Hide implementations.

4) Delegate

Examples

• DTOs

Sample Code

Wrong

Right

Detection

Detection can be automated with sophisticated linters ignoring setters and getters and counting real behavior methods.

Also Known as

• Data Class

Tags

• Anemic
• OOP as Data
• Encapsulation
• Setters/Getters
• Mutability

More info

• Wikipedia
• Refactoring Guru
• Nude Models — Part I : Setters
• Nude Models — Part II : Getters
• How to Decouple a Legacy System

This…

Today I wrote a tweet asking for recommendations for junior developers

I got a lot of very interesting answers. I will group them down here.

Tweets are textual, I chose the more representative, corrected some typos and abbreviations and added some references.

I Agree with

I’m not a Jr Dev, yet. But if I had the experience, my advice to a Jr. Dev and to my future self is; be a student for the rest of your career. Listen to every dev no matter the age and experience. Stay humble, that will make people relied on you and reliable means stable job.

…

Problems

• Readability
• Maintainability
• Coupling

Solutions

1. Use meaningful names
2. Try to avoid flags. They generate coupling.

Sample Code

Wrong

Right

Detection

We can search all the code for bad named flags.

Tags

• Readability

Conclusion

Flags are widespread on production code. We should restrict their usage and use clear and intention revealing names.

Relations

More Info

If you lie to the compiler, it will get its revenge.

Henry Spencer

This article is part of the CodeSmell Series.

Problems

• Coupling
• Extensibility
• Hard to mock

Solutions

1. Use interfaces or traits (if available).
2. Use Dependency Injection.
3. Favor Loose Coupling.

Sample Code

Wrong

Right

Detection

We can use almost any linter to find references to classes. We should not abuse since many uses might be false positives.

Tags

• Coupling

Conclusion

Dependencies to Interfaces make a system less coupled and thus more extensible and testable.

Interfaces change less often than concrete implementations.

Some objects implement many interfaces, declaring which part depends on which interface makes the coupling more granular and the object more cohesive.

Relations

More info

When your code depends on an interface, that dependency is usually very minor and unobtrusive…

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

Right

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

More info

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

Dave Thomas

This…

Todos los tutoriales que he leído durante los últimos 30 años comienzan con el infame ejemplo de “Hola mundo”. Esta podría ser una de las razones por las que escribimos software de mala calidad.