Code Smell 68 - Getters

Getting things is widespread and safe. But it is a very bad practice.

Problems

• Naming

• Information Hiding

• Coupling

• Encapsulation Violation

• Mutability

• Anemic Models

Solutions

1. Avoid Getters

2. Use domain names instead

3. Protect your implementation decisions.

Sample Code

Wrong

	<?php
	final class Window {
	public $width;
	public $height;
	public $children;
	public function getWidth() {
	return $this->width;
	}
	public function getArea() {
	return $this->width * $this->height;
	}
	public function getChildren() {
	return $this->children;
	}
	}

view raw getters.php hosted with ❤ by GitHub

Right

	<?
	final class Window {
	private $width;
	private $height;
	private $children;
	public function width() {
	return $this->width;
	}
	public function area() {
	return $this->height * $this->width;
	}
	public function addChildren($aChild) {
	// Do not expose internal attributes
	return $this->children[] = $aChild;
	}
	}

view raw goodmodel.php hosted with ❤ by GitHub

Detection

Getters coincide in certain scenarios with a true responsibility. It will be reasonable for a window to return its color, and it may accidentally store it as color. So a color() method returning the attribute color might be a good solution.

getColor() breaks bijection since it is implementative and has no real counterpart on our mappers.

Most linters can warn us if they detect anemic models with getters and setters.

Tags

• Information Hiding

Conclusion

Getters and Setters are a poorly established practice. Instead of focusing on object behavior (essential), we are desperate to know object guts (accidental) and violate their implementation.

Relations

Code Smell 28 - Setters

Maxi Contieri ・ Nov 19 '20

#oop #codenewbie #programming #webdev

Code Smell 01 - Anemic Models

Maxi Contieri ・ Oct 20 '20

#codenewbie #oop #beginners #computerscience

Code Smell 64 - Inappropriate Intimacy

Maxi Contieri ・ Mar 27 '21

#codenewbie #codesmell #webdev #oop

More info

Nude Models — Part II : Getters

Maxi Contieri ・ Feb 23 '21

#webdev #programming #oop #tutorial

Credits

Photo by Vidar Nordli-Mathisen on Unsplash

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The value of a prototype is in the education it gives you, not in the code itself.

Alan Cooper

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Software Engineering Great Quotes

Maxi Contieri ・ Dec 28 '20

#codenewbie #programming #quotes #software

Comments

[Jay Jeckel]

Method names should start with verbs. width() isn't a width, it is a method that gets a width and should be named appropriately, ie getWidth(). That goes doubly so for area() which not only isn't an area, it isn't even getting an area, it is calculating an area and the name should reflect that, ie calArea(). You using property naming conventions for methods is a bigger smell than anything you're pointing out.

And I don't know what kind of systems you work in, but a Window class that doesn't allow access to its list of children is best described as nearly useless.

[Maxi Contieri]

what is 'cal' ?

I have asked my child what is 'calArea' and she laughed. She's perfectly aware of what is an area. And she has a friend called 'Cal' btw.

I work in a world class software company and have looooots of windows, we don't access objects since we believe in encapsulation and information hinding principles.
Windows are ok without being accessed