)
            .orElse(null);
    }

    @Nullable
    public List<String> getOutputPropertyNames() {
        return getBeforeExecutionState()
            .map(BeforeExecutionState::getOutputFileLocationSnapshots)
            .map(ImmutableSortedMap::keySet)
            .filter(outputPropertyNames -> !outputPropertyNames.isEmpty())
            .map(ImmutableSet::asList)
            .orElse(null);
    }