| /* |
| * 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.drill.exec.vector.complex; |
| |
| import org.apache.drill.exec.vector.UInt4Vector; |
| import com.google.common.base.Preconditions; |
| |
| /** |
| * Tracks and populate empty values in repeated value vectors. |
| */ |
| public class EmptyValuePopulator { |
| private final UInt4Vector offsets; |
| |
| public EmptyValuePopulator(UInt4Vector offsets) { |
| this.offsets = Preconditions.checkNotNull(offsets, "offsets cannot be null"); |
| } |
| |
| /** |
| * Marks all values since the last set as empty. The last set value is |
| * obtained from underlying offsets vector. |
| * |
| * @param valueCount |
| * the last index (inclusive) in the offsets vector until which empty |
| * population takes place. Given in record (not offset) units |
| * @throws java.lang.IndexOutOfBoundsException |
| * if lastIndex is negative or greater than offsets capacity. |
| */ |
| public void populate(int valueCount) { |
| Preconditions.checkElementIndex(valueCount, Integer.MAX_VALUE); |
| UInt4Vector.Accessor accessor = offsets.getAccessor(); |
| // currentCount is offset counts |
| int currentCount = accessor.getValueCount(); |
| UInt4Vector.Mutator mutator = offsets.getMutator(); |
| if (currentCount == 0) { |
| // Fill in the implicit zero position. |
| |
| mutator.setSafe(0, 0); |
| currentCount = 1; |
| } |
| int previousEnd = accessor.get(currentCount - 1); |
| int offsetCount = valueCount + 1; |
| // Indexes are in offset locations, 1 greater than record indexes |
| for (int i = currentCount; i < offsetCount; i++) { |
| mutator.setSafe(i, previousEnd); |
| } |
| mutator.setValueCount(offsetCount); |
| } |
| } |