src/LINEBot/Event/BaseEvent.php
public function getGroupId()
    {
        if (!$this->isGroupEvent()) {
            throw new InvalidEventSourceException('This event source is not a group type');
        }
        return isset($this->event['source']['groupId'])
            ? $this->event['source']['groupId']
            : null;
    }
public function getGroupId()
    {
        if (!$this->isGroupEvent()) {
            throw new InvalidEventSourceException('This event source is not a group type');
        }
        return isset($this->event['source']['groupId'])
            ? $this->event['source']['groupId']
            : null;
    }
public function getGroupId ( ) { if ( ! $ this -> isGroupEvent ( ) ) { throw new InvalidEventSourceException ( 'This event source is not a group type' ) ; } return isset ( $ this -> event [ 'source' ] [ 'groupId' ] ) ? $ this -> event [ 'source' ] [ 'groupId' ] : null ; }
Returns group ID of the event.

@return string|null
@throws InvalidEventSourceException Raise when called with non group type event.
Returns group ID of the event .