accounts/api/modules/session/models/protocols/BaseHasJoined.php

<?php
namespace api\modules\session\models\protocols;

abstract class BaseHasJoined implements HasJoinedInterface {

    private $username;

    private $serverId;

    public function __construct(string $username, string $serverId) {
        $this->username = trim($username);
        $this->serverId = trim($serverId);
    }

    public function getUsername(): string {
        return $this->username;
    }

    public function getServerId(): string {
        return $this->serverId;
    }

    public function validate(): bool {
        return !$this->isEmpty($this->username) && !$this->isEmpty($this->serverId);
    }

    private function isEmpty($value): bool {
        return $value === null || $value === '';
    }

}