如何使用PHP为类创建函数升级

这是我的代码：

Application.php文件：

class Application {

    private $upgrade;

    public function __construct($upgrade = null) {
        if (!is_null($upgrade) && ($upgrade instanceof ApplicationUpgrade)) {
            $this->setUpgrade($upgrade);

            if ($this->getUpgrade()->getVersion() > $this->getVersion()) {
                $this->getUpgrade()->upgrade();
            }
        }
    }

    public function getVersion() {
        return '1';
    }

    public function getUpgrade() {
        return $this->upgrade;
    }

    public function setUpgrade(ApplicationUpgrade $upgrade) {
        $this->upgrade = $upgrade;
    }

    public function sayHi($name) {
        echo 'Hi ' . $name . '!';
    }
}

文件ApplicationUpgrade.php：

class ApplicationUpgrade {

    public function getVersion() {
        return '1.1';
    }

    public function upgrade() {
        //code upgrade here...
    }

    public function sayHi($name) {
        echo 'Hi ' . $name . ', Method has been upgraded!';
    }
}

现在：

---

我想在升级之前，说一声“嗨，A！”升级后，sayHi返回“Hi A，方法已升级！”

你可以这样做，但我认为这是一个有点不好的做法，但不管怎样，你还是来吧

<?php
class Application {
    public function sayHi($name) {
       if($this->upgrade !== null) {
          $this->upgrade->sayHi($name);
       }
       else {
          echo 'Hi ' . $name . '!';
       }
    }
}

---

此外，我不会为了管理不同的版本而这样做，你们应该在谷歌搜索更好的解决方案，并做一些研究

你们是如何做到这一点的？我们喜欢看到在研究上的努力和不成功的尝试，而不仅仅是在社区中问“如何？”请更好地解释你的问题。我会在谷歌上找到解决方案，因为我不想更改类名。tks！

<?php
class Application {
    public function sayHi($name) {
       if($this->upgrade !== null) {
          $this->upgrade->sayHi($name);
       }
       else {
          echo 'Hi ' . $name . '!';
       }
    }
}

class Application {
  public function sayHi() {
    echo('hi version1');
  }
}

class ApplicationV2 extends Application {
  public function sayHi() {
    echo('hi version2');
  }
}

$app = new ApplicationV2();
$app->sayHi();