PHP:“...的声明应该与...的声明兼容"； [英] PHP: "Declaration of ... should be compatible with that of ..."

问题描述

我想为可 CRUDable(可以保存和删除)的实体创建一个界面.这是我的抽象类:

I'd like to create an interface for entities that are CRUDable (can be saved and deleted). Here is my abstract class:

abstract class AbstractCrudableEntity extends AbstractEntity
{
    abstract public function doSave();
    abstract public function doDelete();
}

我的实现类需要这些方法的几个额外参数.这是实现类的签名:

My implementing class needs a couple extra parameters to those methods. Here is the signature of the implementing class:

class Contact extends AbstractCrudableEntity {
    public function doSave(User $user, \UberClientManager $manager);
    public function doDelete(User $user, \UberClientManager $manager);
}

我理解PHP要求实现类的方法参数与父类相同(有几个问题可以回答这个问题:this，例如).所以这不是问题.

I understand that PHP requires that implementing classes have the same parameters for the methods as the parent class (there are several questions that answer this question: this, for example). So that is not the problem.

然而，我最近在 Symfony 中遇到了一些处理身份验证令牌的代码.类 UsernamePasswordToken 扩展了 AbstractToken，并且在 __construct() 方法中有一组不同的参数:AbstractToken::__construct() 与 UsernamePasswordToken::__construct().

However, I recently came across some code in Symfony dealing with authentication tokens. The class UsernamePasswordToken extends AbstractToken, and has a different set of parameters in the __construct() method: AbstractToken::__construct() versus UsernamePasswordToken::__construct().

我的问题是 Symfony 是如何做到这一点的?这和我的代码有什么区别?

My question is how is Symfony able to do this? What is the difference between this and my code?

推荐答案

重写构造函数是一种特殊情况:

与其他方法不同，当__construct()被与父__construct()不同的参数覆盖时，PHP不会生成E_STRICT级别的错误消息 方法有.

Unlike with other methods, PHP will not generate an E_STRICT level error message when __construct() is overridden with different parameters than the parent __construct() method has.

你可以不能用其他方法做到这一点.

You can not do that with other methods.

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