| /* |
| * 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.store.parquet.columnreaders; |
| |
| import org.apache.drill.common.exceptions.ExecutionSetupException; |
| import org.apache.drill.exec.vector.NullableBitVector; |
| import org.apache.parquet.column.ColumnDescriptor; |
| import org.apache.parquet.format.SchemaElement; |
| import org.apache.parquet.hadoop.metadata.ColumnChunkMetaData; |
| |
| /** |
| * This class is used in conjunction with its superclass to read nullable bit columns in a parquet file. |
| * It currently is using an inefficient value-by-value approach. |
| * TODO - make this more efficient by copying runs of values like in NullableFixedByteAlignedReader |
| * This will also involve incorporating the ideas from the BitReader (the reader for non-nullable bits) |
| * because page/batch boundaries that do not land on byte boundaries require shifting of all of the values |
| * in the next batch. |
| */ |
| final class NullableBitReader extends ColumnReader<NullableBitVector> { |
| |
| NullableBitReader(ParquetRecordReader parentReader, ColumnDescriptor descriptor, ColumnChunkMetaData columnChunkMetaData, |
| boolean fixedLength, NullableBitVector v, SchemaElement schemaElement) throws ExecutionSetupException { |
| super(parentReader, descriptor, columnChunkMetaData, fixedLength, v, schemaElement); |
| } |
| |
| @Override |
| public void readField(long recordsToReadInThisPass) { |
| |
| recordsReadInThisIteration = Math.min(pageReader.pageValueCount |
| - pageReader.valuesRead, recordsToReadInThisPass - valuesReadInCurrentPass); |
| int defLevel; |
| for (int i = 0; i < recordsReadInThisIteration; i++){ |
| defLevel = pageReader.definitionLevels.nextInt(); |
| // if the value is defined |
| if (defLevel == columnDescriptor.getMaxDefinitionLevel()){ |
| valueVec.getMutator().setSafe(i + valuesReadInCurrentPass, |
| pageReader.getValueReader().readBoolean() ? 1 : 0 ); |
| } |
| // otherwise the value is skipped, because the bit vector indicating nullability is zero filled |
| } |
| } |
| |
| } |