src/ModelFilter.php
public function relationIsJoined($relation)
    {
        if ($this->_joinedTables === null) {
            $this->_joinedTables = $this->getJoinedTables();
        }

        return in_array($this->getRelatedTable($relation), $this->_joinedTables, true);
    }
public function relationIsJoined($relation)
    {
        if ($this->_joinedTables === null) {
            $this->_joinedTables = $this->getJoinedTables();
        }

        return in_array($this->getRelatedTable($relation), $this->_joinedTables, true);
    }
public function relationIsJoined ( $ relation ) { if ( $ this -> _joinedTables === null ) { $ this -> _joinedTables = $ this -> getJoinedTables ( ) ; } return in_array ( $ this -> getRelatedTable ( $ relation ) , $ this -> _joinedTables , true ) ; }
Checks if the relation to filter's table is already joined.

@param $relation
@return bool
Checks if the relation to filter s table is already joined .