PHP 抽象 Class 数组保护属性

Question

我在使用 Abstract 类和 OOP 方面有些陌生，所以请多多包涵。
我正在尝试制作员工和客户的列表，但我运行在打印 StoreList class 中的对象数组时遇到了一些麻烦，因为它们都受到保护。
我想要做的是将 storeArray 中的值打印到一个漂亮的列表中。
现在它从抽象 class 中打印出所有内容，使数组过时。
我将在下面包含所有代码，但由于它很长，我想在这里问这个问题。
这是数组在 var_dump 上 index.php 或 Storelistclass.php

时输出的内容

array (size=5)
  0 => 
    object(Employee)[1]
      protected 'userId' => string '1' (length=1)
      protected 'userFirstName' => string 'Joe' (length=3)
      protected 'userLastName' => string 'Longo' (length=5)
      protected 'userTitle' => string 'Employee' (length=8)
  1 => 
    object(Customer)[2]
      protected 'userId' => string '1' (length=1)
      protected 'userFirstName' => string 'Bruce' (length=5)
      protected 'userLastName' => string 'Stark' (length=5)
      protected 'userTitle' => string 'Customer' (length=8)
  2 => 
    object(Customer)[3]
      protected 'userId' => string '2' (length=1)
      protected 'userFirstName' => string 'Tony' (length=4)
      protected 'userLastName' => string 'Wayne' (length=5)
      protected 'userTitle' => string 'Customer' (length=8)
  3 => 
    object(Customer)[4]
      protected 'userId' => string '3' (length=1)
      protected 'userFirstName' => string 'Oliver' (length=6)
      protected 'userLastName' => string 'Wilson' (length=6)
      protected 'userTitle' => string 'Customer' (length=8)
  4 => 
    object(Customer)[5]
      protected 'userId' => string '4' (length=1)
      protected 'userFirstName' => string 'Slade' (length=5)
      protected 'userLastName' => string 'Queen' (length=5)
      protected 'userTitle' => string 'Customer' (length=8)

无论我在哪里尝试通过数组对运行进行 foreach 循环，我都会收到错误消息：无法访问受保护的属性.

foreach($this->storeArray as $data)
{
    echo $data->userFirstName;
}

当我在 User 抽象中创建属性时 class public 它工作得很好，但是 Gets 会过时吗？我应该放弃 Gets 并使它们成为 public ，还是有其他方法？
抱歉，如果这是一个愚蠢的问题，但我真的很想解决这个问题，但失败了。

任何帮助和提示（也包括更新和删除功能）将不胜感激！

这是我现在所有的代码。

index.php:

<?php
include("classes/Userclass.php");
include("classes/Customerclass.php");
include("classes/Employeeclass.php");
include("classes/Storelistclass.php");

$employeeOne = new Employee("1","Joe","Longo","Employee");

$customerOne = new Customer("1","Bruce","Stark","Customer");
$customerTwo = new Customer("2","Tony","Wayne","Customer");
$customerThree = new Customer("3","Oliver","Wilson","Customer");
$customerFour = new Customer("4","Slade","Queen","Customer");

$list = new Storelist($employeeOne);
$list->addCustomer($customerOne);
$list->addCustomer($customerTwo);
$list->addCustomer($customerThree);
$list->addCustomer($customerFour);
?>

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8">
    <!--<link href="includes/stylesheet.css" rel="stylesheet" type="text/css"/>-->
    <title>Store List</title>
  </head>
  <body>

<h1>Test Get Customer</h1>
<p>
  <?php
    echo $customerOne->getUserTitle()." #". $customerOne->getUserId() ."'s First name is ". $customerOne->getUserFirstName() ." and Last name is ". $customerOne->getUserLastName() ."<br/>";
    echo $customerTwo->getUserTitle()." #". $customerTwo->getUserId() ."'s First name is ". $customerTwo->getUserFirstName() ." and Last name is ". $customerTwo->getUserLastName() ."<br/>";
  ?>
</p>

<h1>Test Get Employee</h1>
  <p>
  <?php 
    echo $employeeOne->getUserTitle()." #". $employeeOne->getUserId() ."'s First name is ". $employeeOne->getUserFirstName() ." and Last name is ". $employeeOne->getUserLastName() ."<br/>";
  ?>
</p>

  <h1>Storelist Foreach</h1>
    <p>
      <?php
      $listtest = $list->buildList();
      echo $listtest;
      ?>
  </p>

Customerclass.php:

class Customer extends User
{
    public function userSayHi()
    {
        return "Hello , could i get some help?";
    }
}

Employeeclass.php:

<?php

class Employee extends User
{
    public function userSayHi()
    {
        return 'Hello , how may i help u?';
    }   
}

Userclass.php

<?php

abstract class User
{
    protected $userId;
    protected $userFirstName;
    protected $userLastName;
    protected $userTitle;

    public function __construct($id, $firstName, $lastName, $title) 
     {
        $this->userId = $id;
        $this->userFirstName = $firstName;
        $this->userLastName = $lastName;
        $this->userTitle = $title;
     }

    //Gets
    public function getUserId()
    {
        return $this->userId;
    }

    public function getUserFirstName()
    {
        return $this->userFirstName;
    }

    public function getUserLastName()
    {
        return $this->userLastName;
    }

    public function getUserTitle()
    {
        return $this->userTitle;
    }


    //Sets
    public function setUserId($uId)
    {
        $this->userId = $uId;
    }

    public function setUserFirstName($ufirstName)
    {
        $this->userFirstName = $ufirstName;
    }

    public function setUserLastName($ulastName)
    {
        $this->userLastName = $ulastName;
    }

    public function setUserTitle($uTitle)
    {
        $this->userTitle = $uTitle;
    }

    public abstract function userSayHi();
}

Storelistclass.php

<?php
require_once("Customerclass.php");
require_once("Employeeclass.php");


 class Storelist
 {


    public $storeArray = [];


    public function __construct(Employee $employee)
    {
        array_push($this->storeArray, $employee);
    }


    public function addCustomer(Customer $customer)
    {
        array_push($this->storeArray, $customer);
        //return $this->storeArray;
    }

    public function buildList()
    {



        foreach($this->storeArray as $storeData)
        {
            echo "First Name: ".$storeData->getUserFirstName()."<br/>";
            echo "Last Name: ".$storeData->getUserLastName()."<br/>";
            echo "Is a: ".$storeData->getUserTitle()."<br/>";
            echo "<br/>";
        }

        /*
        //ERROR : Cannot access protected property Employee::$userFirstName 
       foreach($this->storeArray as $storeData)
        {
            echo "First Name: ".$storeData->userFirstName."<br/>";
            echo "Last Name: ".$storeData->userLastName."<br/>";
            echo "Is a: ".$storeData->userTitle."<br/>";
            echo "<br/>";
        }
        */
    }

     public function delete()
     {

     }

     public function update()
     {

     }
 }

Answer 1

解决方案是实际使用您费心定义的 getter 方法 (getUserWhatever())。通过使它们保持 protected 可见性，除了使用您定义的 setUserWhatever() 方法之外无法修改它们，因此您可以进行额外的验证（例如防止非空值）例如，对无效数据抛出异常。因此，它们不能像 public 属性那样从 class 外部直接可变是很有用的。

在您的 Storelist class 中，您定义了 $storeArray 属性具有 public 可见性，这意味着您可以在 [=] 之外阅读它52=] 在 index.php 中。由于您要向该数组添加 Employee 或 Customer 对象，因此这些对象仍可通过其在 $list->storeArray 上的数组键单独寻址。例如，要修改姓氏，您可以使用

// Set the 3rd user's last name
$list->storeArray[2]->setUserLastName('Jones');

同样，在 Storelist class:

中使用 $this 也是可能的

// Inside Storelist
$this->storeArray[2]->setUserLastName('Jones');

因此，您对这些 classes 的布局已经基本步入正轨。我还可以建议一件事；因为您已经创建了通过方法调用将 Customer 或 Employee 对象添加到 Storelist::$storeArray 的方法，而不是直接修改数组：

// You're doing this:
$list = new Storelist($employeeOne);
$list->addCustomer($customerOne);

// And not this (directly modifying storeArray):
$list = new Storelist($employeeOne);
$list->storeArray[] = $customerOne

...然后考虑将 Storelist::$storeArray 定义为 protected 属性以便您可以仅使用其 setter 方法。然后你还需要创建一个 getter 方法来 returns 数组。

class Storelist
{
    // This becomes protected
    protected $storeArray = [];

    // So you need a getter:
    public function getStoreArray()
    {
       return $this->storeArray;
    }
    // etc...
}

从index.php修改数组之后，就不能再直接读取它的元素了。相反，你调用它的 getter 方法：

// You can't do this:
$list->storeArray[2]->setUserLastName('Jones');

// Instead do it via the getter:
$list->getStoreArray()[2]->setUserLastName('Jones');

（注意，上面的 ()[2] 语法需要 PHP 5.4+）

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