3.8. Specification

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    SpecificationInterface.php

    1. <?php
    2.  
    3. namespace DesignPatterns\Behavioral\Specification;
    4.  
    5. interface SpecificationInterface
    6. {
    7.     public function isSatisfiedBy(Item $item): bool;
    8. }

    OrSpecification.php

    1. <?php
    2.  
    3. namespace DesignPatterns\Behavioral\Specification;
    4.  
    5. class PriceSpecification implements SpecificationInterface
    6. {
    7.     /**
    8.      * @var float|null
    9.      */
    10.     private $maxPrice;
    11.     /**
    12.      * @var float|null
    13.      */
    14.     private $minPrice;
    15.  
    16.     /**
    17.      * @param float $minPrice
    18.      * @param float $maxPrice
    19.      */
    20.     public function __construct($minPrice, $maxPrice)
    21.     {
    22.         $this->minPrice = $minPrice;
    23.         $this->maxPrice = $maxPrice;
    24.     }
    25.  
    26.     public function isSatisfiedBy(Item $item): bool
    27.     {
    28.         if ($this->maxPrice !== null && $item->getPrice() > $this->maxPrice) {
    29.             return false;
    30.         }
    31.  
    32.         if ($this->minPrice !== null && $item->getPrice() < $this->minPrice) {
    33.             return false;
    34.         }
    35.         return true;
    36.     }
    37. }

    AndSpecification.php

    NotSpecification.php

    1. <?php
    2.  
    3. namespace DesignPatterns\Behavioral\Specification;
    4.  
    5. class NotSpecification implements SpecificationInterface
    6. {
    7.     /**
    8.      * @var SpecificationInterface
    9.      */
    10.     private $specification;
    11.  
    12.     public function __construct(SpecificationInterface $specification)
    13.     {
    14.         $this->specification = $specification;
    15.     }
    16.  
    17.     public function isSatisfiedBy(Item $item): bool
    18.     {
    19.         return !$this->specification->isSatisfiedBy($item);
    20.     }
    21. }