protected ChannelRef getChannelRef()

in grpc-gcp/src/main/java/com/google/cloud/grpc/GcpManagedChannel.java [1097:1151]
48 lines of code
15 McCabe index (conditional complexity)

  protected ChannelRef getChannelRef(@Nullable String key) {
    if (key == null || key.isEmpty()) {
      return pickLeastBusyChannel(/* forFallback= */ false);
    }
    ChannelRef mappedChannel = affinityKeyToChannelRef.get(key);
    affinityKeyLastUsed.put(key, System.nanoTime());
    if (mappedChannel == null) {
      ChannelRef channelRef = pickLeastBusyChannel(/*forFallback= */ false);
      bind(channelRef, Collections.singletonList(key));
      return channelRef;
    }
    if (!fallbackEnabled) {
      return mappedChannel;
    }
    // Look up if the channelRef is not ready.
    Map<String, Integer> tempMap = fallbackMap.get(mappedChannel.getId());
    if (tempMap == null) {
      // Channel is ready.
      return mappedChannel;
    }
    // Channel is not ready. Look up if the affinity key mapped to another channel.
    Integer channelId = tempMap.get(key);
    if (channelId != null && !fallbackMap.containsKey(channelId)) {
      // Fallback channel is ready.
      if (logger.isLoggable(Level.FINEST)) {
        logger.finest(log("Using fallback channel: %d -> %d", mappedChannel.getId(), channelId));
      }
      fallbacksSucceeded.incrementAndGet();
      return channelRefs.get(channelId);
    }
    // No temp mapping for this key or fallback channel is also broken.
    ChannelRef channelRef = pickLeastBusyChannel(/* forFallback= */ true);
    if (!fallbackMap.containsKey(channelRef.getId())
        && channelRef.getActiveStreamsCount() < DEFAULT_MAX_STREAM) {
      // Got a ready and not an overloaded channel.
      if (channelRef.getId() != mappedChannel.getId()) {
        if (logger.isLoggable(Level.FINEST)) {
          logger.finest(
              log("Setting fallback channel: %d -> %d", mappedChannel.getId(), channelRef.getId()));
        }
        fallbacksSucceeded.incrementAndGet();
        tempMap.put(key, channelRef.getId());
      }
      return channelRef;
    }
    if (logger.isLoggable(Level.FINEST)) {
      logger.finest(log("Failed to find fallback for channel %d", mappedChannel.getId()));
    }
    fallbacksFailed.incrementAndGet();
    if (channelId != null) {
      // Stick with previous mapping if fallback has failed.
      return channelRefs.get(channelId);
    }
    return mappedChannel;
  }