in java/dataflow-connector-examples/src/main/java/com/google/cloud/bigtable/dataflow/example/PubsubWordCount.java [185:197]
private static void injectMessages(BigtablePubsubOptions options) {
String inputFile = options.getInputFile();
String topic = options.getPubsubTopic();
DataflowPipelineOptions copiedOptions = options.as(DataflowPipelineOptions.class);
copiedOptions.setStreaming(false);
copiedOptions.setNumWorkers(INJECTORNUMWORKERS);
copiedOptions.setJobName(copiedOptions.getJobName() + "-injector");
Pipeline injectorPipeline = Pipeline.create(copiedOptions);
injectorPipeline.apply(TextIO.read().from(inputFile))
.apply(ParDo.of(new FilterEmptyStringsFn()))
.apply(PubsubIO.writeStrings().to(topic));
injectorPipeline.run().waitUntilFinish();
}