in src/main/java/org/apache/datasketches/pig/tuple/DataToSketchAlgebraicIntermediateFinal.java [107:142]
public Tuple exec(final Tuple inputTuple) throws IOException {
if (this.isFirstCall_) {
// this is to see in the log which way was used by Pig
Logger.getLogger(getClass()).info("algebraic is used");
this.isFirstCall_ = false;
}
final Union<S> union = new Union<>(this.sketchSize_, this.summarySetOps_);
final DataBag bag = (DataBag) inputTuple.get(0);
if (bag == null) {
throw new IllegalArgumentException("InputTuple.Field0: Bag may not be null");
}
for (final Tuple dataTuple: bag) {
final Object item = dataTuple.get(0);
if (item instanceof DataBag) {
// this is a bag from the Initial function.
// just insert each item of the tuple into the sketch
final UpdatableSketch<U, S> sketch = this.sketchBuilder_.build();
DataToSketch.updateSketch((DataBag) item, sketch);
union.union(sketch);
} else if (item instanceof DataByteArray) {
// This is a sketch from a prior call to the
// Intermediate function. merge it with the
// current sketch.
final Sketch<S> incomingSketch =
Util.deserializeSketchFromTuple(dataTuple, this.summaryDeserializer_);
union.union(incomingSketch);
} else {
// we should never get here.
throw new IllegalArgumentException(
"InputTuple.Field0: Bag contains unrecognized types: " + item.getClass().getName());
}
}
return Util.tupleFactory.newTuple(new DataByteArray(union.getResult().toByteArray()));
}