If it walks like a duck and it quacks like a duck, then it must be a duck
TL;DR: Don't create unnecessary abstractions
Problems
Over Design
Unneeded classes
Solutions
- Use a standard class
Context
Discovering abstractions on the MAPPER is a hard task.
After refining we should remove unneeded abstractions.
Sample Code
Wrong
<?php
Namespace Spelling;
final class Dictionary {
private $words;
function __construct(array $words) {
$this->words = $words;
}
function wordsCount(): int {
return count($this->words);
}
function includesWord(string $subjectToSearch): bool {
return in_array($subjectToSearch, $this->words);
}
}
//This has protocol similar to an abstract datatype dictionary
//And the tests
use PHPUnit\Framework\TestCase;
final class DictionaryTest extends TestCase {
public function test01EmptyDictionaryHasNoWords() {
$dictionary = new Dictionary([]);
$this->assertEquals(0, $dictionary->wordsCount());
}
public function test02SingleDictionaryReturns1AsCount() {
$dictionary = new Dictionary(['happy']);
$this->assertEquals(1, $dictionary->wordsCount());
}
public function test03DictionaryDoesNotIncludeWord() {
$dictionary = new Dictionary(['happy']);
$this->assertFalse($dictionary->includesWord('sadly'));
}
public function test04DictionaryIncludesWord() {
$dictionary = new Dictionary(['happy']);
$this->assertTrue($dictionary->includesWord('happy'));
}
}
Right
<?php
Namespace Spelling;
// final class Dictionary is no longer needed
//The tests use a standard class
//In PHP we use associative arrays
//Java an other languages have HashTables, Dictionaries etc. etc.
use PHPUnit\Framework\TestCase;
final class DictionaryTest extends TestCase {
public function test01EmptyDictionaryHasNoWords() {
$dictionary = [];
$this->assertEquals(0, count($dictionary));
}
public function test02SingleDictionaryReturns1AsCount() {
$dictionary = ['happy'];
$this->assertEquals(1, count($dictionary));
}
public function test03DictionaryDoesNotIncludeWord() {
$dictionary = ['happy'];
$this->assertFalse(in_array('sadly', $dictionary));
}
public function test04DictionaryIncludesWord() {
$dictionary = ['happy'];
$this->assertTrue(in_array('happy', $dictionary));
}
}
Detection
[X] SemiAutomatic
Based on protocols, we should remove some unnecessary classes
Tags
- Protocols
Exceptions
Sometimes we need to optimize collections for performance reasons if we have enough strong evidence.
Conclusion
We need to clean up code from time to time.
Specialized collections are a good starting point.
Relations
Code Smell 111 - Modifying Collections While Traversing
Maxi Contieri ・ Dec 19 '21
More Info
Credits
Photo by Pisit Heng on Unsplash
Most of the effort in the software business goes into the maintenance of code that already exists.
Wietse Venema
Software Engineering Great Quotes
Maxi Contieri ・ Dec 28 '20
This article is part of the CodeSmell Series.