file.php

class UnderscoreNamingStrategy implements NamingStrategyInterface
{
    /**
     * {@inheritDoc}
     */
    public function getNameForExtraction($name, $context = null)
    {
        return ltrim(strtolower(preg_replace('/[A-Z]/', '_$0', $name)), '_');
    }

    /**
     * {@inheritDoc}
     */
    public function getNameForHydration($name, $context = null)
    {
        return lcfirst(str_replace(' ', '', ucwords(str_replace('_', ' ', strtolower($name)))));
    }
}