beam_sql_part_4

beam_sql_part_4.java

[..]
.apply("transform_to_string", ParDo.of(new RowToString()))
.apply("write_to_gcs", TextIO.write().to("gs://batch-pipeline-sql/output/output.csv").withoutSharding());
[..]
//ParDo for Row (SQL) -> String
    public static class RowToString extends DoFn<Row, String> {
        @ProcessElement
        public void processElement(ProcessContext c) {
            String line = c.element().getValues()
                    .stream()
                    .map(Object::toString)
                    .collect(Collectors.joining(","));
            c.output(line);
        }
    }
[..]