| /* |
| * Copyright 2016, Yahoo! Inc. |
| * Licensed under the terms of the Apache License 2.0. See LICENSE file at the project root for terms. |
| */ |
| |
| package com.yahoo.sketches.pig.frequencies; |
| |
| import java.io.IOException; |
| |
| import org.apache.log4j.Logger; |
| import org.apache.pig.EvalFunc; |
| import org.apache.pig.data.DataBag; |
| import org.apache.pig.data.DataByteArray; |
| import org.apache.pig.data.Tuple; |
| |
| import com.yahoo.sketches.ArrayOfItemsSerDe; |
| import com.yahoo.sketches.frequencies.ItemsSketch; |
| |
| /** |
| * This is to calculate the intermediate pass (combiner) or the final pass |
| * (reducer) of an Algebraic sketch operation. This may be called multiple times |
| * (from the mapper and from the reducer). It will receive a bag of values |
| * returned by either the Intermediate or the Initial stages, so |
| * it needs to be able to differentiate between and interpret both types. |
| * |
| * @param <T> Type of item |
| */ |
| public abstract class UnionFrequentItemsSketchAlgebraicIntermediateFinal<T> extends EvalFunc<Tuple> { |
| private int sketchSize_; |
| private ArrayOfItemsSerDe<T> serDe_; |
| private boolean isFirstCall_ = true; |
| |
| /** |
| * Default constructor to make pig validation happy. |
| */ |
| public UnionFrequentItemsSketchAlgebraicIntermediateFinal() {} |
| |
| public UnionFrequentItemsSketchAlgebraicIntermediateFinal( |
| final int sketchSize, final ArrayOfItemsSerDe<T> serDe) { |
| sketchSize_ = sketchSize; |
| serDe_ = serDe; |
| } |
| |
| @Override |
| public Tuple exec(final Tuple inputTuple) throws IOException { |
| if (isFirstCall_) { |
| // this is to see in the log which way was used by Pig |
| Logger.getLogger(getClass()).info("algebraic is used"); |
| isFirstCall_ = false; |
| } |
| final ItemsSketch<T> sketch = new ItemsSketch<T>(sketchSize_); |
| |
| final DataBag bag = (DataBag) inputTuple.get(0); |
| if (bag == null) { |
| throw new IllegalArgumentException("InputTuple.Field0: Bag may not be null"); |
| } |
| |
| for (Tuple dataTuple: bag) { |
| final Object item = dataTuple.get(0); |
| if (item instanceof DataBag) { |
| // this is from a prior call to the initial function, so there is a nested bag. |
| for (final Tuple innerTuple: (DataBag) item) { |
| final ItemsSketch<T> incomingSketch = Util.deserializeSketchFromTuple(innerTuple, serDe_); |
| sketch.merge(incomingSketch); |
| } |
| } else if (item instanceof DataByteArray) { |
| // This is a sketch from a call to the Intermediate function |
| // Merge it with the current sketch. |
| final ItemsSketch<T> incomingSketch = Util.deserializeSketchFromTuple(dataTuple, serDe_); |
| if (incomingSketch.isEmpty()) { continue; } |
| 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, serDe_); |
| } |
| } |