class Groups

class Groups {
    
    /**
     * @var string[]
     */
    private readonly array $groups;
    
    /**
     * @param string|string[] $groups The groups to define on the attribute target
     */
    public function __construct(string|array $groups) {
        $this->groups = (array) $groups;
        if (!$this->groups) {
            throw new InvalidArgumentException(\sprintf('Parameter given to "%s" cannot be empty.', static::class));
        }
        foreach ($this->groups as $group) {
            if (!\is_string($group) || '' === $group) {
                throw new InvalidArgumentException(\sprintf('Parameter given to "%s" must be a string or an array of non-empty strings.', static::class));
            }
        }
    }
    
    /**
     * @return string[]
     */
    public function getGroups() : array {
        return $this->groups;
    }

}