public function is_singleton( $id ) {
		if ( ! is_string( $id ) ) {
			throw new InvalidArgumentException( 'Invalid argument. Must be string.' );
		}

		if ( ! $this->exists( $id ) ) {
			return false;
		}

		$id = $this->get_class_prefix( $id );

		return $this->values[$id]['singleton'] === true;
	}
public function is_singleton( $id ) {
		if ( ! is_string( $id ) ) {
			throw new InvalidArgumentException( 'Invalid argument. Must be string.' );
		}

		if ( ! $this->exists( $id ) ) {
			return false;
		}

		$id = $this->get_class_prefix( $id );

		return $this->values[$id]['singleton'] === true;
	}
public function is_singleton ( $ id ) { if ( ! is_string ( $ id ) ) { throw new InvalidArgumentException ( 'Invalid argument. Must be string.' ) ; } if ( ! $ this -> exists ( $ id ) ) { return false ; } $ id = $ this -> get_class_prefix ( $ id ) ; return $ this -> values [ $ id ] [ 'singleton' ] === true ; }
Determine if a given type is a singleton or not.

@param string $id

@throws InvalidArgumentException if argument is not string.

@return bool
Determine if a given type is a singleton or not .