SpecificationInterface.php

<?php
namespace DesignPatterns\Specification;

/**
 * An interface for a specification
 */
interface SpecificationInterface
{
    /**
     * A boolean evaluation indicating if the object meets the specification
     * 
     * @param Item $item
     * 
     * @return bool
     */
    public function isSatisfiedBy(Item $item);

    /**
     * Creates a logical AND specification
     * 
     * @param SpecificationInterface $spec

     */
    public function plus(SpecificationInterface $spec);

    /**
     * Creates a logical OR specification
     * 
     * @param SpecificationInterface $spec

     */
    public function either(SpecificationInterface $spec);

    /**
     * Creates a logical not specification
     */
    public function not();
}