Can i define an object inside a Class constructor? - php

Question

The clean code says, that is not recommended to initialize objects, use if statement or other things in the __constructor.
I have a class in which I used elements in the constructor which are not allowed.
How to rebuild it to conform to the rules?
I searched on google! But I do not really understand and I hope that I will succeed in understanding with this particular example.
The full code is also available on github: https://github.com/KoreLewi/21-blackjack-game
public function __construct(array $Cards = array())
{
if (empty($Cards)) {
$Cards = $this->initEnglishDeck();
}
parent::__construct($Cards);
}
public function initEnglishDeck()
{
$arrCards = array();
foreach ($this->suits as $suit) {
foreach ($this->cards as $card) {
$arrCards[] = new Card($suit, $card);
}
}
return $arrCards;
}
The full code is also available on github: https://github.com/KoreLewi/21-blackjack-game

Answer 1

The pattern is Dependency Injection rather than initialising your dependencies internaly.
One way to "fix" your code is to have a CardDeck Interface and multiple (or just in this case) a EnglishDeck class which implements CardDeck.
And in all the classes which require a card deck you inject it in the constructor like this:
class Game {
/**
* #var CardDeck
*/
private $cardDeck
public function __construct(CardDeck $cardDeck) {
$this->cardDeck = $cardDeck
}
}
In that case your Game class would still work even if you decide it to pass him another type of CardDeck, e.g. FrenchDeck which would also implement the CardDeck interface.

Answer 2

You could:
Move the if statement into the initEnglishDeck() function.
public function __construct(array $Cards = array()) {
$Cards = $this->initEnglishDeck($Cards);
parent::__construct($Cards);
}
public function initEnglishDeck($cards = array()) {
if(!empty($cards)) return $cards;
$arrCards = array();
foreach ($this->suits as $suit) {
foreach ($this->cards as $card) {
$arrCards[] = new Card($suit, $card);
}
}
return $arrCards;
}