/**
  * Creates a connection to the Solr server as configured in $this->configuration.
  */
 protected function connect()
 {
     if (!$this->solr) {
         $this->solr = new Client();
         $this->solr->createEndpoint($this->configuration + array('key' => $this->server->id()), TRUE);
         $this->getSolrHelper()->setSolr($this->solr);
     }
 }