public HostSpec getHost()

in wrapper/src/main/java/software/amazon/jdbc/RoundRobinHostSelector.java [74:131]
45 lines of code
11 McCabe index (conditional complexity)

  public HostSpec getHost(
      final @NonNull List<HostSpec> hosts,
      final @NonNull HostRole role,
      final @Nullable Properties props) throws SQLException {

    lock.lock();
    try {
      final List<HostSpec> eligibleHosts = hosts.stream()
          .filter(hostSpec ->
              role.equals(hostSpec.getRole()) && hostSpec.getAvailability().equals(HostAvailability.AVAILABLE))
          .sorted(Comparator.comparing(HostSpec::getHost))
          .collect(Collectors.toList());

      if (eligibleHosts.isEmpty()) {
        throw new SQLException(Messages.get("HostSelector.noHostsMatchingRole", new Object[]{role}));
      }

      // Create new cache entries for provided hosts if necessary. All hosts point to the same cluster info.
      createCacheEntryForHosts(eligibleHosts, props);
      final String currentClusterInfoKey = eligibleHosts.get(0).getHost();
      final RoundRobinClusterInfo clusterInfo = roundRobinCache.get(currentClusterInfoKey);

      final HostSpec lastHost = clusterInfo.lastHost;
      int lastHostIndex = -1;

      // Check if lastHost is in list of eligible hosts. Update lastHostIndex.
      if (lastHost != null) {
        for (int i = 0; i < eligibleHosts.size(); i++) {
          if (eligibleHosts.get(i).getHost().equals(lastHost.getHost())) {
            lastHostIndex = i;
          }
        }
      }

      final int targetHostIndex;
      // If the host is weighted and the lastHost is in the eligibleHosts list.
      if (clusterInfo.weightCounter > 0 && lastHostIndex != -1) {
        targetHostIndex = lastHostIndex;
      } else {
        if (lastHostIndex != -1 && lastHostIndex != eligibleHosts.size() - 1) {
          targetHostIndex = lastHostIndex + 1;
        } else {
          targetHostIndex = 0;
        }

        final Integer weight = clusterInfo.clusterWeightsMap.get(eligibleHosts.get(targetHostIndex).getHostId());
        clusterInfo.weightCounter = weight == null ? clusterInfo.defaultWeight : weight;
      }

      clusterInfo.weightCounter--;
      clusterInfo.lastHost = eligibleHosts.get(targetHostIndex);

      return eligibleHosts.get(targetHostIndex);

    } finally {
      lock.unlock();
    }
  }