public ProcessorType getProcessorType() {
        if (processorType == null) {
            if (processor != null) {
                processorType = getProcessor().getProcessorType();
            } else {
                processorType = ProcessorType.PIPELINE;
            }
        }
        return processorType;
    }
Zero means processing tasks are unbounded.
stroom-core-shared/src/main/java/stroom/processor/shared/ProcessorFilter.java