@Override
public PDone apply(PCollection<Integer> input) {
// Apply an operation so that this is a composite transform.
input.apply(Count.<Integer>perElement());
return PDone.in(input.getPipeline());
}
@Override
public PDone apply(PCollection<T> input) {
if (topic == null) {
throw new IllegalStateException("need to set the topic of a PubsubIO.Write transform");
}
return PDone.in(input.getPipeline());
}