code: public int getChannelIdForStreamId(Number streamId) {
          int channelId = (int) (streamId.doubleValue() * 5) - 1;
          if (log.isTraceEnabled()) {
              log.trace("Channel id: {} requested for stream id: {}", channelId, streamId);
          }
          return channelId;
      }
docs: Return channel id for given stream id.
  
  @param streamId
  Stream id
  @return ID of channel that belongs to the stream