/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.
*/
package com.nexr.platform.hive.udf;
import org.apache.commons.lang.StringUtils;
import org.apache.hadoop.hive.ql.exec.Description;
import org.apache.hadoop.hive.ql.exec.UDFArgumentException;
import org.apache.hadoop.hive.ql.exec.UDFArgumentTypeException;
import org.apache.hadoop.hive.ql.metadata.HiveException;
import org.apache.hadoop.hive.ql.udf.UDFType;
import org.apache.hadoop.hive.ql.udf.generic.GenericUDF;
import org.apache.hadoop.hive.serde.Constants;
import org.apache.hadoop.hive.serde2.io.DoubleWritable;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspectorConverters;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspectorConverters.Converter;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspectorUtils;
import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspectorUtils.ObjectInspectorCopyOption;
import org.apache.hadoop.hive.serde2.objectinspector.primitive.PrimitiveObjectInspectorFactory;
import org.apache.hadoop.io.LongWritable;
import org.apache.hive.pdk.HivePdkUnitTest;
import org.apache.hive.pdk.HivePdkUnitTests;
@Description(name = "max",
value = "_FUNC_(hash_key, order_by_col1, order_by_col2 ...) " +
"- Returns the max value in a group of values",
extended = "Example:\n"
+ " > SELECT _FUNC_(HASH(p1, p2), order_by_col1, order_by_col2, ... ) FROM (\n"
+ " > SELECT ~ FROM table DISTRIBUTE BY HASH(p1,p2) " +
"SORT BY p1,p2,order_by_col1, order_by_col2 DESC, ... \n"
+ " > );")
@HivePdkUnitTests(
setup = "", cleanup = "",
cases = {
@HivePdkUnitTest(
query = "SELECT t.empno, t.deptno, t.sal, nexr_max(hash(t.deptno),t.sal) as sal_max"
+" FROM ("
+" select a.empno, a.deptno, a.sal from emp a"
+" distribute by hash(a.deptno)"
+" sort BY a.deptno, a.empno desc"
+" ) t;",
result ="7934\t10\t1300\t1300\n"
+"7839\t10\t5000\t5000\n"
+"7782\t10\t2450\t5000\n"
+"7902\t20\t3000\t3000\n"
+"7876\t20\t1100\t3000\n"
+"7788\t20\t3000\t3000\n"
+"7566\t20\t2975\t3000\n"
+"7369\t20\t800\t3000\n"
+"7900\t30\t950\t950\n"
+"7844\t30\t1500\t1500\n"
+"7698\t30\t2850\t2850\n"
+"7654\t30\t1250\t2850\n"
+"7521\t30\t1250\t2850\n"
+"7499\t30\t1600\t2850")
}
)
@UDFType(deterministic = false, stateful = true)
public class GenericUDFMax extends GenericUDF {
private final LongWritable longResult = new LongWritable();
private final DoubleWritable doubleResult = new DoubleWritable();
private ObjectInspector hashOI,valueOI,prevHashStandardOI,resultOI,maxStandardOI;
private Object prevHash,max;
@Override
public ObjectInspector initialize(ObjectInspector[] arguments) throws UDFArgumentException {
if (arguments.length != 2) {
throw new UDFArgumentException("Exactly two argument is expected.");
}
for(int i=0;i<arguments.length;i++){
if (arguments[i].getCategory() != ObjectInspector.Category.PRIMITIVE) {
throw new UDFArgumentTypeException(i,
"Only primitive type arguments are accepted but "
+ arguments[i].getTypeName() + " is passed.");
}
}
String t = arguments[1].getTypeName();
if (t.equals(Constants.TINYINT_TYPE_NAME)||
t.equals(Constants.SMALLINT_TYPE_NAME)||
t.equals(Constants.INT_TYPE_NAME)||
t.equals(Constants.BIGINT_TYPE_NAME)) {
resultOI = PrimitiveObjectInspectorFactory.writableLongObjectInspector;
} else if (t.equals(Constants.FLOAT_TYPE_NAME)||
t.equals(Constants.DOUBLE_TYPE_NAME)||
t.equals(Constants.STRING_TYPE_NAME)) {
resultOI = PrimitiveObjectInspectorFactory.writableDoubleObjectInspector;
} else{
throw new UDFArgumentTypeException(1,
"Only numeric or string type arguments are accepted but "
+ arguments[1].getTypeName() + " is passed.");
}
hashOI = arguments[0];
valueOI = arguments[1];
prevHashStandardOI=ObjectInspectorUtils.getStandardObjectInspector(hashOI,ObjectInspectorCopyOption.JAVA);
maxStandardOI= ObjectInspectorUtils.getStandardObjectInspector(valueOI,ObjectInspectorCopyOption.JAVA);
return resultOI;
}
@Override
public Object evaluate(DeferredObject[] arguments) throws HiveException {
Object hash = arguments[0].get();
Object value = arguments[1].get();
if (prevHash==null||ObjectInspectorUtils.compare(prevHash,prevHashStandardOI,hash,hashOI)!=0) {
max = ObjectInspectorUtils.copyToStandardObject(value,valueOI,ObjectInspectorCopyOption.JAVA);
}
else{
if (ObjectInspectorUtils.compare(max,maxStandardOI,value,valueOI)<0){
max = ObjectInspectorUtils.copyToStandardObject(value,valueOI,ObjectInspectorCopyOption.JAVA);
}
}
prevHash=ObjectInspectorUtils.copyToStandardObject(hash,hashOI, ObjectInspectorCopyOption.JAVA);
Converter converter = ObjectInspectorConverters.getConverter(maxStandardOI, resultOI);
if(resultOI.getTypeName()==Constants.DOUBLE_TYPE_NAME){
DoubleWritable maxW = (DoubleWritable)converter.convert(max);
doubleResult.set(maxW.get());
return doubleResult;
}
LongWritable maxW = (LongWritable)converter.convert(max);
longResult.set(maxW.get());
return longResult;
}
@Override
public String getDisplayString(String[] children) {
return "max(" + StringUtils.join(children, ',') + ")";
}
}