1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 18 package org.apache.arrow.vector.complex; 19 20 import org.apache.arrow.util.Preconditions; 21 import org.apache.arrow.vector.UInt4Vector; 22 23 /** 24 * A helper class that is used to track and populate empty values in repeated value vectors. 25 */ 26 public class EmptyValuePopulator { 27 private final UInt4Vector offsets; 28 EmptyValuePopulator(UInt4Vector offsets)29 public EmptyValuePopulator(UInt4Vector offsets) { 30 this.offsets = Preconditions.checkNotNull(offsets, "offsets cannot be null"); 31 } 32 33 /** 34 * Marks all values since the last set as empty. The last set value is obtained from underlying offsets vector. 35 * 36 * @param lastIndex the last index (inclusive) in the offsets vector until which empty population takes place 37 * @throws java.lang.IndexOutOfBoundsException if lastIndex is negative or greater than offsets capacity. 38 */ populate(int lastIndex)39 public void populate(int lastIndex) { 40 if (lastIndex < 0) { 41 throw new IndexOutOfBoundsException("index cannot be negative"); 42 } 43 final int lastSet = Math.max(offsets.getValueCount() - 1, 0); 44 final int previousEnd = offsets.get(lastSet); //0 ? 0 : accessor.get(lastSet); 45 for (int i = lastSet; i < lastIndex; i++) { 46 offsets.setSafe(i + 1, previousEnd); 47 } 48 offsets.setValueCount(lastIndex + 1); 49 } 50 51 } 52