inanzzz | PHP ile Decorator tasarım deseni örneği

Decorator tasarım deseni, bir classın mevcut olan işlevine dinamik olarak yeni işlevlik eklemeye yarar. Bu işlem yapılırken mevcut olan class herhangi bir şekilde değişikliğe uğramaz. Aşağıdaki örnekte, Mercedes marka bir araç satacağız ama mevcut olan özelliklerine ekstradan tiptronik vites ve deri koltuklar ekleyeceğiz.

Classlar

MercedesSaleInterface

interface MercedesSaleInterface
{
    public function calculatePrice(): float;

    public function getDescription(): string;
}

MercedesSale

class MercedesSale implements MercedesSaleInterface
{
    public function calculatePrice(): float
    {
        return 20000.96;
    }

    public function getDescription(): string
    {
        return 'Mercedes';
    }
}

CarSaleDecorator

abstract class CarSaleDecorator implements MercedesSaleInterface
{
    protected $mercedesSale;

    public function __construct(MercedesSaleInterface $mercedesSale)
    {
        $this->mercedesSale = $mercedesSale;
    }
}

Tiptronic

class Tiptronic extends CarSaleDecorator
{
    public function calculatePrice(): float
    {
        return $this->mercedesSale->calculatePrice() + 1000.01;
    }

    public function getDescription(): string
    {
        return $this->mercedesSale->getDescription() . ' with tiptronic transmission';
    }
}

LeatherSeat

class LeatherSeat extends CarSaleDecorator
{
    public function calculatePrice(): float
    {
        return $this->mercedesSale->calculatePrice() + 100.02;
    }

    public function getDescription(): string
    {
        return $this->mercedesSale->getDescription() . ' with leather seats';
    }
}

Kullanım

$mercedesSale = new MercedesSale();
echo $mercedesSale->calculatePrice().PHP_EOL;
echo $mercedesSale->getDescription().PHP_EOL;

$mercedesSale = new Tiptronic($mercedesSale);
echo $mercedesSale->calculatePrice().PHP_EOL;
echo $mercedesSale->getDescription().PHP_EOL;

$mercedesSale = new LeatherSeat($mercedesSale);
echo $mercedesSale->calculatePrice().PHP_EOL;
echo $mercedesSale->getDescription().PHP_EOL;

Sonuç

20000.96
Mercedes

21000.97
Mercedes with tiptronic transmission

21100.99
Mercedes with tiptronic transmission with leather seats