Strategy design pattern example

<?php

interface Strategy {
    public function calculate(array $criteria): array;
}

class TwoThousandNineteenStrategy implements Stragety {
    public function calculate(array $criteria): array
    {
        // query and calculation for 2019.
    }
}

class TwoThousandEighteenStrategy implements Stragety {
    public function calculate(array $criteria): array
    {
        // query and calculation for 2018.
    }
}

class StrategyFactory
{
    public function create(int $year): Strategy
    {
        if ($year === 2018) {
            return new TwoThousandEighteenStrategy();
        }
        if ($year === 2019) {
            return new TwoThousandNineteenStrategy();
        }

        throw new InvalidArgumentException('Missing strategy for given year');
    }
}

$strategyFactory = new StrategyFactory();

foreach ($years as $year) {
    $stategy = $strategyFactory->create($year);
    resultOfTheYear = $strategy->calcule([]);
}