如何使用Doctrine的ArrayCollection :: exists方法

Question

我必须检查一个Email实体是否已经存在ArrayCollection但我必须对电子邮件进行检查作为字符串(实体包含一个ID和一些与其他entites的关系,因此我使用一个单独的表来保存所有电子邮件).

现在,在第一次我写这个代码:

    /**
     * A new Email is adding: check if it already exists.
     *
     * In a normal scenario we should use $this->emails->contains().
     * But it is possible the email comes from the setPrimaryEmail method.
     * In this case, the object is created from scratch and so it is possible it contains a string email that is
     * already present but that is not recognizable as the Email object that contains it is created from scratch.
     *
     * So we hav to compare Email by Email the string value to check if it already exists: if it exists, then we use
     * the already present Email object, instead we can persist the new one securely.
     *
     * @var Email $existentEmail
     */
    foreach ($this->emails as $existentEmail) {
        if ($existentEmail->getEmail()->getEmail() === $email->getEmail()) {
            // If the two email compared as strings are equals, set the passed email as the already existent one.
            $email = $existentEmail;
        }
    }

但阅读ArrayCollection课程后,我看到的方法exists似乎是一种更加优雅的方式来做同样的事情.

但我不知道如何使用它:有人可以解释我如何使用这个方法给出上面的代码？

Answer 1

当然,在PHP中,Closure是一个简单的匿名函数.您可以按如下方式重写代码:

    $exists =  $this->emails->exists(function($key, $element) use ($email){
        return $email->getEmail() === $element->getEmail()->getEmail();
        }
    );

希望这有帮助