FlatMap extends Operator<OutputT> implements TypeAware.Output<OutputT> { public static <InputT> UsingBuilder<InputT> of(PCollection<InputT> input) { return named(null).of(input); } private  FlatMap(
      @Nullable String name,
      UnaryFunctor<InputT, OutputT> functor,
      @Nullable TypeDescriptor<OutputT> outputType,
      @Nullable ExtractEventTime<InputT> evtTimeFn,
      Duration allowedTimestampSkew); static UsingBuilder<InputT> of(PCollection<InputT> input); static OfBuilder named(@Nullable String name); UnaryFunctor<InputT, OutputT> getFunctor(); Optional<ExtractEventTime<InputT>> getEventTimeExtractor(); Duration getAllowedTimestampSkew();  }
@Test public void testBuild_ImplicitName() { final PCollection<String> dataset = TestUtils.createMockDataset(TypeDescriptors.strings()); final PCollection<String> mapped = FlatMap.of(dataset).using((String s, Collector<String> c) -> c.collect(s)).output(); final FlatMap map = (FlatMap) TestUtils.getProducer(mapped); assertFalse(map.getName().isPresent()); }