Method getNextHost

lib/prepare-handler.js:173–201

* Gets the next host from the query plan. * @param {Iterator} iterator * @param {ProfileManager} profileManager * @param {Object} [triedHosts] * @return {Host|null}

(iterator, profileManager, triedHosts)

   * @return {Host|null}
   */
  static getNextHost(iterator, profileManager, triedHosts) {
    let host;
    // Get a host that is UP in a sync loop
    while (true) {
      const item = iterator.next();
      if (item.done) {
        return null;
      }

      host = item.value;

      // set the distance relative to the client first
      const distance = profileManager.getDistance(host);
      if (distance === types.distance.ignored) {
        //If its marked as ignore by the load balancing policy, move on.
        continue;
      }

      if (host.isUp()) {
        break;
      }

      if (triedHosts) {
        triedHosts[host.address] = 'Host considered as DOWN';
      }
    }

    return host;
  }

  /**
   * Prepares all queries on a single host.