Symfony'nin dependency injection componentinin kullanımını göstermek amacıyla hazırlanmış örnek sınıf.

DependencyInjection.php

<?php

    /**
     * Looking for tests DependencyInjectionTest.php
     */

require_once 'vendor/autoload.php';

interface iCurrency {
    public function getExchangeRate();
}

interface iObject{
    public function setInstance(iCurrency $currency);
    public function getValue();
}

class Dollar implements iCurrency {
    public function getExchangeRate() {
        return '1.93';
    }
}

class Euro implements iCurrency {
    public function getExchangeRate() {
        return '1.57';
    }
}

class Money implements iObject {
    public function setInstance(iCurrency $currency) {
        $this->_currency = $currency;
    }
    
    public function getValue() {
        return $this->_currency->getExchangeRate();
    }

}

class Controller {
    
    public function setObject(iCurrency $instanceObject, iObject $object) {
        $this->_object = $object;
        $this->_object->setInstance($instanceObject);
    }

    public function getTLtoCurrency($turkishLira) {
        if( !is_float($turkishLira)) {
            throw new InvalidArgumentException("This value is not float.");
        }
        
        $TLtoCurrency = $turkishLira * $this->_object->getValue();
        return $TLtoCurrency;
    }
}

use Symfony\Component\DependencyInjection\ContainerBuilder;
use Symfony\Component\DependencyInjection\Reference;

$cont = new ContainerBuilder;

$cont->register('dollar', 'Dollar');

$cont->register('money', 'Money');

$cont->register('control', 'Controller')
     ->addMethodCall('setObject', array(new Reference('dollar'), new Reference('money')));

try {
    $convertedTL = $cont->get('control')->getTLtoCurrency(2.00);
    echo $convertedTL;
} catch(InvalidArgumentException $e) {
    echo $e->getMessage();
}