ArrayAccess, Iteratable and countable object

gistfile1.php

<?php

namespace xxx\AppBundle\Model\User\Search;

class UserSearch implements \ArrayAccess, \IteratorAggregate, \Countable
{

    private $data = [];

    public function &__get ($key)
    {
        return $this->data[$key];
    }

    public function __set($key,$value)
    {
        $this->data[$key] = $value;
    }

    public function __isset ($key)
    {
        return isset($this->data[$key]);
    }

    public function __unset($key)
    {
        unset($this->data[$key]);
    }

    public function offsetSet($offset,$value)
    {
        if (is_null($offset)) {
            $this->data[] = $value;
        } else {
            $this->data[$offset] = $value;
        }
    }

    public function offsetExists($offset)
    {
        return isset($this->data[$offset]);
    }

    public function offsetUnset($offset)
    {
        if ($this->offsetExists($offset)) {
            unset($this->data[$offset]);
        }
    }

    public function offsetGet($offset)
    {
        return $this->offsetExists($offset) ? $this->data[$offset] : null;
    }

    public function getIterator() {
        return new ArrayIterator($this->data);
    }

    public function count()
    {
        return count($this->data);
    }

}