Demo for Factory Design Pattern in PHP

factoryDesignPatternDemo.php

<?php

class FactoryMain
{

    private $type;

    function __construct($type)
    {
        $this->type = $type;
    }

    public function getInstance() : TypeInterface
    {
        if ( !class_exists($this->type)) {
            throw new Error('Class implementation missing');
        }

        return new $this->type();
    }
}

interface TypeInterface{
    public function someMethod();
}

class TypeA implements TypeInterface
{

    function someMethod()
    {
        return 'from TypeA';
    }
}

class TypeB implements TypeInterface
{

    function someMethod()
    {
        return 'from TypeB';
    }
}

try {
    $obj = new FactoryMain('TypeB');
    $ins = $obj->getInstance();
    echo $ins->someMethod();
} catch (\Throwable $t) {
    echo $t->getMessage();
}