/* * 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 hivemall.tools.array; import hivemall.utils.hadoop.HiveUtils; import hivemall.utils.lang.StringUtils; import org.apache.hadoop.hive.ql.exec.Description; import org.apache.hadoop.hive.ql.exec.UDFArgumentException; 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.serde2.objectinspector.ListObjectInspector; import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector; import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspectorUtils; import org.apache.hadoop.hive.serde2.objectinspector.PrimitiveObjectInspector; import org.apache.hadoop.hive.serde2.objectinspector.primitive.PrimitiveObjectInspectorFactory; import org.apache.hadoop.io.IntWritable; @Description(name = "argmin", value = "_FUNC_(array<T> a) - Returns the first index of the minimum value", extended = "SELECT argmin(array(5,2,0,1));\n" + "2") @UDFType(deterministic = true, stateful = false) public final class ArgminUDF extends GenericUDF { private ListObjectInspector listOI; private PrimitiveObjectInspector elemOI; private IntWritable result; @Override public ObjectInspector initialize(ObjectInspector[] argOIs) throws UDFArgumentException { if (argOIs.length != 1) { throw new UDFArgumentException("argmin takes exactly one argument: " + argOIs.length); } this.listOI = HiveUtils.asListOI(argOIs[0]); this.elemOI = HiveUtils.asPrimitiveObjectInspector(listOI.getListElementObjectInspector()); this.result = new IntWritable(); return PrimitiveObjectInspectorFactory.writableIntObjectInspector; } @Override public IntWritable evaluate(DeferredObject[] arguments) throws HiveException { Object arg0 = arguments[0].get(); if (arg0 == null) { return null; } int index = -1; Object minObject = null; final int size = listOI.getListLength(arg0); for (int i = 0; i < size; i++) { Object ai = listOI.getListElement(arg0, i); if (ai == null) { continue; } if (minObject == null) { minObject = ai; index = i; } else { final int cmp = ObjectInspectorUtils.compare(ai, elemOI, minObject, elemOI); if (cmp < 0) { minObject = ai; index = i; } } } result.set(index); return result; } @Override public String getDisplayString(String[] children) { return "argmin(" + StringUtils.join(children, ',') + ')'; } }