public Map<SystemStream, Integer> getPriorityStreams() {
    Set<SystemStream> allInputs = taskConfig.getAllInputStreams();

    Map<SystemStream, Integer> priorityStreams = new HashMap<>();
    for (SystemStream systemStream : allInputs) {
      int priority = streamConfig.getPriority(systemStream);
      if (priority >= 0) {
        priorityStreams.put(systemStream, priority);
      }
    }
    return Collections.unmodifiableMap(priorityStreams);
  }
Gets the priority of every SystemStream for which the priority
was explicitly configured with a value &gt;=0.

@return  the explicitly-configured stream priorities as a map from
         SystemStream to the configured priority value. Streams that
         were not explicitly configured with a priority are not returned.
samza-core/src/main/java/org/apache/samza/config/DefaultChooserConfig.java