PHP \DesignPatterns\Behavioral\Specification\AbstractSpecification \DesignPatterns\Behavioral\Specification\PriceSpecification \DesignPatterns\Behavioral\Specification\Not \DesignPatterns\Behavioral\Specification\SpecificationInterface \DesignPatterns\Behavioral\Specification\Plus \DesignPatterns\Behavioral\Specification\AbstractSpecification \DesignPatterns\Behavioral\Specification\Either \DesignPatterns\Behavioral\Specification\Item Fields Constants Constructors Methods private