I'm trying one of the beam google dataflow pipeline examples, but i'm bumping into a exception regarding MapElements and methods SingleFunction / SerializableFunction calls. The code snippet is the following:
static class ParseTableRowJson extends SimpleFunction<String, TableRow> {
@Override
public TableRow apply(String input) {
try {
return Transport.getJsonFactory().fromString(input, TableRow.class);
} catch (IOException e) {
throw new RuntimeException("Failed parsing table row json", e);
}
}
}
......
p.apply(TextIO.read().from(options.getInput()))
.apply(MapElements.via(new ParseTableRowJson()))
.apply(new ComputeTopSessions(samplingThreshold))
.apply("Write",
TextIO.write().withoutSharding().to(options.getOutput()));
The exception in that its an ambiguous call to the methods:
Ambiguous method call. Both
via (SimpleFunction<String, TableRow>) in MapElements and
via (SerializableFunction) in MapElements match
Has someone else bumped into the same exception and got a way around it?
The full example is in github ( https://github.com/apache/beam/blob/master/examples/java/src/main/java/org/apache/beam/examples/complete/TopWikipediaSessions.java ).
Thanks,
Fernando
This seems to have been fixed in the code at HEAD. Specifically, MapElements
no longer has two static versions of via
. Short-term, you can either install Beam from HEAD or update the example to use ParDo
directly by making the ParseTableRowJson
a DoFn
instead of a SimpleFunction
.
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