Examples with ImpulseSourceFunction org.apache.beam.runners.flink.translation.functions.ImpulseSourceFunction used on opensource projects

Example 1 with ImpulseSourceFunction

use of org.apache.beam.runners.flink.translation.functions.ImpulseSourceFunction in project beam by apache.

the class FlinkStreamingPortablePipelineTranslator method translateFlatten.

private <T> void translateFlatten(String id, RunnerApi.Pipeline pipeline, StreamingTranslationContext context) {
    RunnerApi.PTransform transform = pipeline.getComponents().getTransformsOrThrow(id);
    Map<String, String> allInputs = transform.getInputsMap();
    if (allInputs.isEmpty()) {
        // create an empty dummy source to satisfy downstream operations
        // we cannot create an empty source in Flink, therefore we have to
        // add the flatMap that simply never forwards the single element
        long shutdownAfterIdleSourcesMs = context.getPipelineOptions().getShutdownSourcesAfterIdleMs();
        DataStreamSource<WindowedValue<byte[]>> dummySource = context.getExecutionEnvironment().addSource(new ImpulseSourceFunction(shutdownAfterIdleSourcesMs));
        DataStream<WindowedValue<T>> result = dummySource.<WindowedValue<T>>flatMap((s, collector) -> {
        // never return anything
        }).returns(new CoderTypeInformation<>(WindowedValue.getFullCoder((Coder<T>) VoidCoder.of(), GlobalWindow.Coder.INSTANCE), context.getPipelineOptions()));
        context.addDataStream(Iterables.getOnlyElement(transform.getOutputsMap().values()), result);
    } else {
        DataStream<T> result = null;
        // Determine DataStreams that we use as input several times. For those, we need to uniquify
        // input streams because Flink seems to swallow watermarks when we have a union of one and
        // the same stream.
        HashMultiset<DataStream<T>> inputCounts = HashMultiset.create();
        for (String input : allInputs.values()) {
            DataStream<T> current = context.getDataStreamOrThrow(input);
            inputCounts.add(current, 1);
        }
        for (String input : allInputs.values()) {
            DataStream<T> current = context.getDataStreamOrThrow(input);
            final int timesRequired = inputCounts.count(current);
            if (timesRequired > 1) {
                current = current.flatMap(new FlatMapFunction<T, T>() {

                    private static final long serialVersionUID = 1L;

                    @Override
                    public void flatMap(T t, Collector<T> collector) {
                        collector.collect(t);
                    }
                });
            }
            result = (result == null) ? current : result.union(current);
        }
        context.addDataStream(Iterables.getOnlyElement(transform.getOutputsMap().values()), result);
    }
}