How to use

Combine$GloballyAsSingletonView

in

org.apache.beam.sdk.transforms

/**
 * Returns a {@link PTransform} that produces a {@code PCollectionView} whose elements are the
 * result of combining elements per-window in the input {@code PCollection}. If a value is
 * requested from the view for a window that is not present, the result of applying the {@code
 * CombineFn} to an empty input set will be returned.
 */
public GloballyAsSingletonView<InputT, OutputT> asSingletonView() {
 return new GloballyAsSingletonView<>(fn, fnDisplayData, insertDefault, fanout);
}

 @Override
 public PTransformReplacement<PCollection<InputT>, PValue> getReplacementTransform(
   AppliedPTransform<PCollection<InputT>, PValue, PTransform<PCollection<InputT>, PValue>>
     transform) {
  Combine.GloballyAsSingletonView<?, ?> combineTransform =
    (Combine.GloballyAsSingletonView) transform.getTransform();
  return PTransformReplacement.of(
    PTransformReplacements.getSingletonMainInput(transform),
    new BatchViewOverrides.BatchViewAsSingleton(
      runner,
      findCreatePCollectionView(transform),
      (CombineFn) combineTransform.getCombineFn(),
      combineTransform.getFanout()));
 }
}

@Test
public void testCombineGetName() {
 assertEquals("Combine.globally(SumInts)", Combine.globally(new SumInts()).getName());
 assertEquals(
   "Combine.GloballyAsSingletonView",
   Combine.globally(new SumInts()).asSingletonView().getName());
 assertEquals("Combine.perKey(Test)", Combine.perKey(new TestCombineFn()).getName());
 assertEquals(
   "Combine.perKeyWithFanout(Test)",
   Combine.perKey(new TestCombineFn()).withHotKeyFanout(10).getName());
}