package brickhouse.udf.sketch;
/**
* Copyright 2012 Klout, Inc
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
**/
import java.util.List;
import org.apache.hadoop.hive.ql.exec.Description;
import org.apache.hadoop.hive.ql.exec.UDF;
import org.apache.hadoop.hive.ql.exec.UDFArgumentException;
import org.apache.hadoop.hive.ql.metadata.HiveException;
import org.apache.hadoop.hive.ql.udf.generic.GenericUDF;
import org.apache.hadoop.hive.serde2.objectinspector.ConstantObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.ListObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspectorFactory;
import org.apache.hadoop.hive.serde2.objectinspector.PrimitiveObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.StandardListObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector.Category;
import org.apache.hadoop.hive.serde2.objectinspector.PrimitiveObjectInspector.PrimitiveCategory;
import org.apache.hadoop.hive.serde2.objectinspector.primitive.IntObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.primitive.PrimitiveObjectInspectorFactory;
import org.apache.hadoop.hive.serde2.objectinspector.primitive.StringObjectInspector;
import org.apache.hadoop.io.IntWritable;
import org.apache.log4j.Logger;
import brickhouse.analytics.uniques.SketchSet;
/*
* Take an array of strings, and convert to a truncated array,
* representing a sketch set of those strings.
*
* Useful for converting legacy lists of high-reach users,
* and converting to sketch sets.
*/
@Description(name="convert_to_sketch",
value = "_FUNC_(x) - Truncate a large array of strings, and return a list of strings representing a sketch of those items "
)
public class ConvertToSketchUDF extends GenericUDF {
private static final Logger LOG = Logger.getLogger( ConvertToSketchUDF.class);
private ListObjectInspector listInspector;
private StringObjectInspector listElemInspector;
private StandardListObjectInspector retInspector;
private int sketchSetSize = SketchSetUDAF.DEFAULT_SKETCH_SET_SIZE;
@Override
public Object evaluate(DeferredObject[] arg0) throws HiveException {
Object obj = arg0[0].get();
if(obj == null) {
return null;
}
List oldList = listInspector.getList(obj);
SketchSet sketchSet = new SketchSet( sketchSetSize);
for( Object oldObj : oldList) {
if( oldObj == null) {
LOG.warn(" Object in uninspected List is null");
} else {
String newStr = listElemInspector.getPrimitiveJavaObject(oldObj);
sketchSet.addItem(newStr);
}
}
return sketchSet.getMinHashItems();
}
@Override
public String getDisplayString(String[] arg0) {
return "convert_to_sketch(" + arg0[0] + ")";
}
@Override
public ObjectInspector initialize(ObjectInspector[] arg0)
throws UDFArgumentException {
if(arg0.length > 2) {
throw new UDFArgumentException("convert_to_sketch takes an array of strings, and an optional sketch set size.");
}
if(arg0[0].getCategory() != Category.LIST) {
throw new UDFArgumentException("convert_to_sketch takes an array of strings, and an optional sketch set size.");
}
listInspector = (ListObjectInspector) arg0[0];
if(listInspector.getListElementObjectInspector().getCategory() != Category.PRIMITIVE
|| ((PrimitiveObjectInspector)listInspector.getListElementObjectInspector()).getPrimitiveCategory() != PrimitiveCategory.STRING ) {
throw new UDFArgumentException("convert_to_sketch takes an array of strings, and an optional sketch set size.");
}
listElemInspector = (StringObjectInspector) listInspector.getListElementObjectInspector();
if(arg0.length > 1) {
if( !(arg0[1] instanceof IntObjectInspector)
|| !(arg0[1] instanceof ConstantObjectInspector)) {
throw new UDFArgumentException("sketch set size must be a constant int value.");
}
IntWritable sizeInt = (IntWritable)((ConstantObjectInspector)arg0[1]).getWritableConstantValue();
sketchSetSize = sizeInt.get();
}
retInspector = ObjectInspectorFactory.getStandardListObjectInspector(PrimitiveObjectInspectorFactory.javaStringObjectInspector);
return retInspector;
}
}