src/Riak/Command/Builder/MapReduce/FetchObjects.php
public function buildReducePhase($bucket = '', $key = '', $source = '', $language = 'javascript', $keep = true)
    {
        $this->setPhase('reduce', $this->assemblePhaseData($bucket, $key, $source, $language), $keep);

        return $this;
    }
public function buildReducePhase($bucket = '', $key = '', $source = '', $language = 'javascript', $keep = true)
    {
        $this->setPhase('reduce', $this->assemblePhaseData($bucket, $key, $source, $language), $keep);

        return $this;
    }
buildReducePhase

Allows you to define the Reduce Query Phase by using parameters

@param string $bucket
@param string $key
@param string $source
@param string $language
@param bool $keep

@return $this