public Set<String> getStreamIds() {
    // StreamIds are not allowed to have '.' so the first index of '.' marks the end of the streamId.
    return subset(STREAMS_PREFIX).keySet().stream().map(key -> key.substring(0, key.indexOf(".")))
      .distinct().collect(Collectors.toSet());
  }
Gets the distinct stream IDs of all the streams defined in the config

@return collection of stream IDs
samza-core/src/main/java/org/apache/samza/config/StreamConfig.java