sminnee / silverstripe-framework

	 * @return string|array The class of the one-to-one component, or an array of all one-to-one components and

	 * 							their classes.

	 */

	public function hasOne($component = null) {

		if($component) {

			Deprecation::notice(

				'4.0',

				'Please use DataObject::hasOneComponent() instead of passing a component name to hasOne()',

				Deprecation::SCOPE_GLOBAL

			);

			return $this->hasOneComponent($component);

		}

		return (array)Config::inst()->get($this->class, 'has_one', Config::INHERITED);

	}

	/**

	 * Return data for a specific has_one component.

	 * @param string $component Deprecated - Name of component

	 * @return array|null

	 */

	public function manyManyExtraFields($component = null) {

		if($component) {

			Deprecation::notice(

				'4.0',

				'Please use DataObject::manyManyExtraFieldsForComponent() instead of passing a component name

					to manyManyExtraFields()',

				Deprecation::SCOPE_GLOBAL

			);

			return $this->manyManyExtraFieldsForComponent($component);

		}

		return Config::inst()->get($this->class, 'many_many_extraFields', Config::INHERITED);

	}

	/**

	 * Return the many-to-many extra fields specification for a specific component.