Basho\Riak\Command\Builder\QueryIndex::validate PHP Method

    public function validate()
    {
        $this->required('Bucket');
        $this->required('IndexName');
        if ($this->isMatchQuery()) {
            $this->required('MatchValue');
        } else {
            $this->required('LowerBound');
            $this->required('UpperBound');
        }
    }