Code Smell 01 - Anemic Models

Your objects have no behavior.

TL;DR: Don't use objects as data structures

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
Writer / Reader mismatch.

Solutions

1) Find Responsibilities.

2) Protect your attributes.

3) Hide implementations.

4) Delegate

Examples

DTOs

Sample Code

Wrong

<?

class Window {
    public $height;
    public $width;

    function getHeight() {
        return $this->height;
    }

    function setHeight($height) {
        $this->height = $height;
    }

    function getWidth() {
        return $this->width;
    }

    function setWidth($width) {
        $this->width = $width;
    }

}

Right

<?

final Class Window{ 

  function area(){
    //...
  }

  function open(){
    //..
  }

  function isOpen(){
    //..
  }

}

Detection

Sophisticated linters can automate detection.
They should ignore setters and getters and count real behavior methods.

Also Known as

Data Class

Conclusion

Avoid anemic models. Focus always on protocol instead of data.
Behaviour is essential, data is accidental.

Relations

Code Smell 28 - Setters

Maxi Contieri ・ Nov 19 '20

#oop #codenewbie #programming #webdev

Code Smell 15 - Missed Preconditions

Maxi Contieri ・ Nov 3 '20

#codenewbie #oop #tutorial

More info

Object-oriented programming increases the value of these metrics by managing this complexity. The most effective tool available for dealing with complexity is abstraction. Many types of abstraction can be used, but encapsulation is the main form of abstraction by which complexity is managed in object-oriented programming.

Rebecca Wirfs-Brock

Software Engineering Great Quotes

Maxi Contieri ・ Dec 28 '20

#codenewbie #programming #quotes #software

Credits

Photo by Stacey Vandergriff on Unsplash

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

Last update: 2021/05/30