in src/main/java/org/apache/datasketches/pig/frequencies/DataToFrequentItemsSketchAlgebraicIntermediateFinal.java [59:87]
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 was used");
this.isFirstCall_ = false;
}
final ItemsSketch<T> sketch = new ItemsSketch<>(this.sketchSize_);
final DataBag bag = (DataBag) inputTuple.get(0);
for (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
DataToFrequentItemsSketch.updateSketch((DataBag)item, 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 ItemsSketch<T> incomingSketch = Util.deserializeSketchFromTuple(dataTuple, this.serDe_);
sketch.merge(incomingSketch);
} else {
// we should never get here.
throw new IllegalArgumentException(
"InputTuple.Field0: Bag contains unrecognized types: " + item.getClass().getName());
}
}
return Util.serializeSketchToTuple(sketch, this.serDe_);
}