Document::getProvider

public function getProvider(): ?DataProvider
{
	if(isset($this->fields[Template::MAIN_PROVIDER_PLACEHOLDER]))
	{
		$mainField = $this->fields[Template::MAIN_PROVIDER_PLACEHOLDER];

		return DataProviderManager::getInstance()->createDataProvider(
			$mainField,
			$this->getValue(Template::MAIN_PROVIDER_PLACEHOLDER)
		);
	}

	if($this->data['PROVIDER'] && $this->data['VALUE'])
	{
		return DataProviderManager::getInstance()->getDataProvider($this->data['PROVIDER'], $this->data['VALUE']);
	}

	return null;
}