test.php

<?php
/**
 * Created by PhpStorm.
 * User: chentao
 * Date: 2021/7/3
 * Time: 8:59 PM
 */

class Bug {
    public $value;

    public function __construct(int $value)
    {
        $this->value = $value;
    }
}

abstract class Programmer {
    protected $next;

    public function setNext(Programmer $next) {
        $this->next = $next;
    }

    abstract function handle(Bug $bug);
}

class NewbieProgrammer extends Programmer{
    public function handle(Bug $bug){
        if ($bug->value > 0 && $bug->value <= 20) {
            $this->solve($bug);
        } elseif ($this->next != null){
            $this->next->handle($bug);
        }
    }

    private function solve(Bug $bug){
        echo "菜鸟程序员解决一个难度为：".$bug->value."的bug".PHP_EOL;
    }
}

/**
 * 中级程序员
 * Class MiddleProgrammer
 */
class MiddleProgrammer extends Programmer{
    public function handle(Bug $bug){
        if ($bug->value > 20 && $bug->value <= 50) {
            $this->solve($bug);
        } elseif ($this->next != null){
            $this->next->handle($bug);
        }
    }

    public function solve(Bug $bug){
        echo "中级程序员解决一个难度为：".$bug->value."的bug".PHP_EOL;
    }
}

class AdvanceProgrammer extends Programmer{
    public function handle(Bug $bug){
        if ($bug->value > 50) {
            $this->solve($bug);
        } elseif ($this->next != null){
            $this->next->handle($bug);
        }
    }

    public function solve(Bug $bug){
        echo "高级程序员解决一个难度为：".$bug->value."的bug".PHP_EOL;
    }
}


$easy = new Bug(10);
$normal = new Bug(25);
$hard = new Bug(60);

$newbie = new NewbieProgrammer();
$middle= new MiddleProgrammer();
$advance = new AdvanceProgrammer();

$newbie->setNext($middle);
$middle->setNext($advance);

$newbie->handle($easy);
$newbie->handle($normal);
$newbie->handle($hard);