| /* |
| * Copyright 2017, 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.hll; |
| |
| import java.io.IOException; |
| |
| import org.apache.log4j.Logger; |
| import org.apache.pig.Accumulator; |
| import org.apache.pig.Algebraic; |
| import org.apache.pig.EvalFunc; |
| import org.apache.pig.backend.executionengine.ExecException; |
| import org.apache.pig.data.DataBag; |
| import org.apache.pig.data.DataByteArray; |
| import org.apache.pig.data.DataType; |
| import org.apache.pig.data.Tuple; |
| |
| import com.yahoo.sketches.hll.HllSketch; |
| import com.yahoo.sketches.hll.TgtHllType; |
| import com.yahoo.sketches.hll.Union; |
| |
| /** |
| * This is a Pig UDF that builds Sketches from data. |
| * This class implements both the <i>Accumulator</i> and <i>Algebraic</i> interfaces. |
| * |
| * @author Alexander Saydakov |
| */ |
| public class DataToSketch extends EvalFunc<DataByteArray> implements Accumulator<DataByteArray>, Algebraic { |
| |
| static final int DEFAULT_LG_K = 12; |
| static final TgtHllType DEFAULT_HLL_TYPE = TgtHllType.HLL_4; |
| |
| private DataByteArray emptySketch_; // this is to cash an empty sketch |
| |
| private final int lgK_; |
| private final TgtHllType tgtHllType_; |
| private Union accumUnion_; |
| private boolean isFirstCall_; |
| |
| /** |
| * Constructor with default lgK and target HLL type |
| */ |
| public DataToSketch() { |
| this(DEFAULT_LG_K, DEFAULT_HLL_TYPE); |
| } |
| |
| /** |
| * Constructor with given lgK as string and default target HLL type. |
| * |
| * @param lgK in a form of a String |
| */ |
| public DataToSketch(final String lgK) { |
| this(Integer.parseInt(lgK), DEFAULT_HLL_TYPE); |
| } |
| |
| /** |
| * Constructor with given lgK and target HLL type as strings |
| * |
| * @param lgK in a form of a String |
| * @param tgtHllType in a form of a String |
| */ |
| public DataToSketch(final String lgK, final String tgtHllType) { |
| this(Integer.parseInt(lgK), TgtHllType.valueOf(tgtHllType)); |
| } |
| |
| /** |
| * Base constructor. |
| * |
| * @param lgK parameter controlling the sketch size and accuracy |
| * @param tgtHllType HLL type of the resulting sketch |
| */ |
| public DataToSketch(final int lgK, final TgtHllType tgtHllType) { |
| super(); |
| lgK_ = lgK; |
| tgtHllType_ = tgtHllType; |
| } |
| |
| /** |
| * Top-level exec function. |
| * This method accepts an input Tuple containing a Bag of one or more inner <b>Datum Tuples</b> |
| * and returns a single serialized HllSketch as a DataByteArray. |
| * |
| * <b>Datum Tuple</b> is a Tuple containing a single field, which can be one of the following |
| * (Java type: Pig type): |
| * <ul> |
| * <li>Byte: BYTE</li> |
| * <li>Integer: INTEGER</li> |
| * <li>Long: LONG</li> |
| * <li>Float: FLOAT</li> |
| * <li>Double: DOUBLE</li> |
| * <li>String: CHARARRAY</li> |
| * <li>DataByteArray: BYTEARRAY</li> |
| * </ul> |
| * |
| * @param inputTuple A tuple containing a single bag, containing Datum Tuples. |
| * @return serialized HllSketch |
| * @see "org.apache.pig.EvalFunc.exec(org.apache.pig.data.Tuple)" |
| * @throws IOException from Pig. |
| */ |
| |
| @Override |
| public DataByteArray exec(final Tuple inputTuple) throws IOException { |
| if (isFirstCall_) { |
| Logger.getLogger(getClass()).info("Exec was used"); |
| isFirstCall_ = false; |
| } |
| if (inputTuple == null || inputTuple.size() == 0) { |
| if (emptySketch_ == null) { |
| emptySketch_ = new DataByteArray(new HllSketch(lgK_, tgtHllType_).toCompactByteArray()); |
| } |
| return emptySketch_; |
| } |
| final Union union = new Union(lgK_); |
| final DataBag bag = (DataBag) inputTuple.get(0); |
| updateUnion(bag, union); |
| return new DataByteArray(union.getResult(tgtHllType_).toCompactByteArray()); |
| } |
| |
| /** |
| * An <i>Accumulator</i> version of the standard <i>exec()</i> method. Like <i>exec()</i>, |
| * accumulator is called with a bag of Datum Tuples. Unlike <i>exec()</i>, it doesn't serialize the |
| * result at the end. Instead, it can be called multiple times, each time with another bag of |
| * Datum Tuples to be input to the sketch. |
| * |
| * @param inputTuple A tuple containing a single bag, containing Datum Tuples. |
| * @see #exec |
| * @see "org.apache.pig.Accumulator.accumulate(org.apache.pig.data.Tuple)" |
| * @throws IOException by Pig |
| */ |
| @Override |
| public void accumulate(final Tuple inputTuple) throws IOException { |
| if (isFirstCall_) { |
| Logger.getLogger(getClass()).info("Accumulator was used"); |
| isFirstCall_ = false; |
| } |
| if (inputTuple == null || inputTuple.size() == 0) { return; } |
| final DataBag bag = (DataBag) inputTuple.get(0); |
| if (bag == null) { return; } |
| if (accumUnion_ == null) { |
| accumUnion_ = new Union(lgK_); |
| } |
| updateUnion(bag, accumUnion_); |
| } |
| |
| /** |
| * Returns the sketch that has been built up by multiple calls to {@link #accumulate}. |
| * |
| * @return serialized HllSketch |
| * @see "org.apache.pig.Accumulator.getValue()" |
| */ |
| @Override |
| public DataByteArray getValue() { |
| if (accumUnion_ == null) { |
| if (emptySketch_ == null) { |
| emptySketch_ = new DataByteArray(new HllSketch(lgK_, tgtHllType_).toCompactByteArray()); |
| } |
| return emptySketch_; |
| } |
| return new DataByteArray(accumUnion_.getResult(tgtHllType_).toCompactByteArray()); |
| } |
| |
| /** |
| * Cleans up the UDF state after being called using the {@link Accumulator} interface. |
| * |
| * @see "org.apache.pig.Accumulator.cleanup()" |
| */ |
| @Override |
| public void cleanup() { |
| accumUnion_ = null; |
| } |
| |
| @Override |
| public String getInitial() { |
| return AlgebraicInitial.class.getName(); |
| } |
| |
| @Override |
| public String getIntermed() { |
| return DataToSketchAlgebraicIntermediate.class.getName(); |
| } |
| |
| @Override |
| public String getFinal() { |
| return DataToSketchAlgebraicFinal.class.getName(); |
| } |
| |
| static void updateUnion(final DataBag bag, final Union union) throws ExecException { |
| //Bag is not empty. process each innerTuple in the bag |
| for (final Tuple innerTuple: bag) { |
| final Object f0 = innerTuple.get(0); // consider only field 0 |
| if (f0 == null) { |
| continue; |
| } |
| final byte type = innerTuple.getType(0); |
| |
| switch (type) { |
| case DataType.NULL: |
| break; |
| case DataType.BYTE: |
| union.update((byte) f0); |
| break; |
| case DataType.INTEGER: |
| union.update((int) f0); |
| break; |
| case DataType.LONG: |
| union.update((long) f0); |
| break; |
| case DataType.FLOAT: |
| union.update((float) f0); |
| break; |
| case DataType.DOUBLE: |
| union.update((double) f0); |
| break; |
| case DataType.BYTEARRAY: { |
| final DataByteArray dba = (DataByteArray) f0; |
| union.update(dba.get()); |
| break; |
| } |
| case DataType.CHARARRAY: { |
| final String str = (String) f0; |
| // conversion to char[] avoids costly UTF-8 encoding |
| union.update(str.toCharArray()); |
| break; |
| } |
| default: |
| throw new IllegalArgumentException("Field 0 of innerTuple must be one of " |
| + "NULL, BYTE, INTEGER, LONG, FLOAT, DOUBLE, BYTEARRAY or CHARARRAY. " |
| + "Given Type = " + DataType.findTypeName(type) |
| + ", Object = " + f0.toString()); |
| } |
| } |
| } |
| |
| } |