public static SystemStream getSystemStreamFromNames(String systemStreamName) {
    int idx = systemStreamName.indexOf('.');
    if (idx < 0) {
      throw new IllegalArgumentException("No '.' in stream name '" + systemStreamName +
          "'. Stream names should be in the form 'system.stream'");
    }
    return new SystemStream(
        systemStreamName.substring(0, idx),
        systemStreamName.substring(idx + 1, systemStreamName.length()));
  }
Returns a SystemStream object based on the system stream name given. For
example, kafka.topic would return SystemStream("kafka", "topic").

@param systemStreamName name of the system stream
@return the {@link SystemStream} for the {@code systemStreamName}
samza-core/src/main/java/org/apache/samza/util/StreamUtil.java