locale_domain_model.php

<?php

namespace App\Packages\FrontPage\Shared\Domain\Models;

use InvalidArgumentException;

class Locale
{
    private const LOCALE = [
        'en',
        'ja',
        'pt',
        'vi',
        'zh',
    ];

    private string $locale;

    public function __construct(string $locale)
    {
        if (!$this->isValidLocale($locale)) {
            throw new InvalidArgumentException();
        }

        $this->locale = $locale;
    }

    public function getLocale(): string
    {
        return $this->locale;
    }

    /**
     * 設定できるlocaleの値の配列を返す
     *
     * @return array
     */
    public static function availableLocales(): array
    {
        return self::LOCALE;
    }

    private function isValidLocale(string $locale): bool
    {
        return in_array($locale, self::LOCALE);
    }
}