SourabhBadhya commented on code in PR #3893: URL: https://github.com/apache/hive/pull/3893#discussion_r1061117096
########## ql/src/java/org/apache/hadoop/hive/ql/udf/generic/GenericUDFArraySlice.java: ########## @@ -0,0 +1,73 @@ +/* + * 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 org.apache.hadoop.hive.ql.udf.generic; + +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.serde2.objectinspector.ListObjectInspector; +import org.apache.hadoop.hive.serde2.objectinspector.ObjectInspector; +import org.apache.hadoop.hive.serde2.objectinspector.PrimitiveObjectInspector; +import org.apache.hadoop.hive.serde2.objectinspector.primitive.IntObjectInspector; + +import java.util.Collections; +import java.util.List; +import java.util.stream.Collectors; + +/** + * GenericUDFArraySlice. + */ +@Description(name = "array_slice", value = "_FUNC_(array, start, length) - Returns the subset or range of elements from" + + " an array (subarray).", extended = "Example:\n" + " > SELECT _FUNC_(array(1, 2, 3,4), 2,2) FROM src LIMIT 1;\n" + + " 3,4") +public class GenericUDFArraySlice extends AbstractGenericUDFArrayBase { + private static final String FUNC_NAME = "ARRAY_SLICE"; + private static final int START_IDX = 1; + private static final int LENGTH_IDX = 2; + + public GenericUDFArraySlice() { + super(FUNC_NAME, 3, 3, ObjectInspector.Category.LIST); + } + + @Override public ObjectInspector initialize(ObjectInspector[] arguments) throws UDFArgumentException { + ObjectInspector defaultOI = super.initialize(arguments); + // Check whether start and length inputs are of integer type + checkArgIntPrimitiveCategory((PrimitiveObjectInspector) arguments[START_IDX], FUNC_NAME, START_IDX); + checkArgIntPrimitiveCategory((PrimitiveObjectInspector) arguments[LENGTH_IDX], FUNC_NAME, LENGTH_IDX); + return defaultOI; + } + + @Override public Object evaluate(DeferredObject[] arguments) throws HiveException { + + Object array = arguments[ARRAY_IDX].get(); + if (arrayOI.getListLength(array) == 0) { + return Collections.emptyList(); + } else if (arrayOI.getListLength(array) < 0) { + return null; + } + + List<?> retArray = ((ListObjectInspector) argumentOIs[ARRAY_IDX]).getList(array); + int start = ((IntObjectInspector) argumentOIs[START_IDX]).get(arguments[START_IDX].get()); + int length = ((IntObjectInspector) argumentOIs[LENGTH_IDX]).get(arguments[LENGTH_IDX].get()); + // return empty list if start/length are out of range of the array + if (start + length > retArray.size()) { + return Collections.emptyList(); Review Comment: Why are we returning empty list when the size of array is lesser than start + length? Shouldn't an exception be thrown specifying that the window of subarray requested is not within the array because of invalid input? Also I believe this check must be at the beginning of `evaluate()`. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: gitbox-unsubscr...@hive.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: gitbox-unsubscr...@hive.apache.org For additional commands, e-mail: gitbox-h...@hive.apache.org
