DynamicCollection.php

<?php

namespace YourVendor\YourBundle;

use Doctrine\Common\Collections\ArrayCollection;
use Doctrine\Common\Collections\Collection;

class DynamicCollection extends ArrayCollection
{
    public function __call($method, $arguments)
    {
        $property = substr($method, 3, strlen($method));
        $property = lcfirst($property);

        if ('get' == substr($method, 0, 3)) {
            if (!$this->containsKey($property)) {
                throw new \BadMethodCallException(
                    "Undefined property '$property'. Did you set it first?"
                );
            }

            return $this->get($property);
        } elseif ('set' == substr($method, 0, 3)) {
            $this->set($property, $arguments[0]);

            return $this;
        } elseif ('add' == substr($method, 0, 3)) {
            if (!$this->containsKey($property)) {
                $this->set($property, new ArrayCollection());
            }
            $this->get($property)->add($arguments[0]);

            return $this;
        } else {
            throw new \BadMethodCallException(
                "Undefined method '$method'. The method name must start with " .
                "either add, set or get!"
            );
        }
    }

    public function toArrayRecursive()
    {
        $resultedArray = array();
        foreach ($this->toArray() as $key => $element) {
            if (is_object($element) && 'Exercise\ProgramBundle\Model\DynamicCollection' == get_class($element)) {
                $resultedArray[$key] = $element->toArrayRecursive();
            } elseif (is_object($element) && in_array('Doctrine\Common\Collections\Collection', class_implements($element))) {
                $resultedArray[$key] = $element->toArray();
            } else {
                $resultedArray[$key] = $element;
            }
        }

        return $resultedArray;
    }
}