| /* |
| * 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.accessor.reader; |
| |
| import org.apache.drill.common.types.TypeProtos.MinorType; |
| import org.apache.drill.exec.vector.accessor.ColumnAccessors.UInt1ColumnReader; |
| import org.apache.drill.exec.vector.accessor.ColumnReaderIndex; |
| import org.apache.drill.exec.vector.complex.UnionVector; |
| |
| public class NullStateReaders { |
| |
| public static final RequiredStateReader REQUIRED_STATE_READER = new RequiredStateReader(); |
| public static final NullStateReader NULL_STATE_READER = new AlwaysNullStateReader(); |
| |
| private NullStateReaders() { } |
| |
| /** |
| * Dummy implementation of a null state reader for cases in which the |
| * value is never null. Use the {@link NullStateReaders#REQUIRED_STATE_READER} instance |
| * for this case. |
| */ |
| |
| protected static class RequiredStateReader implements NullStateReader { |
| |
| @Override |
| public void bindIndex(ColumnReaderIndex rowIndex) { } |
| |
| @Override |
| public boolean isNull() { return false; } |
| } |
| |
| /** |
| * Holder for the NullableVector wrapper around a bits vector and a |
| * data vector. Manages the bits vector to extract the nullability |
| * value. |
| * <p> |
| * This class allows the same reader to handle both the required and |
| * nullable cases; the only difference is how nulls are handled. |
| */ |
| |
| protected static class NullableIsSetVectorStateReader implements NullStateReader { |
| |
| private final VectorAccessor nullableAccessor; |
| private final UInt1ColumnReader isSetReader; |
| |
| public NullableIsSetVectorStateReader(VectorAccessor nullableAccessor) { |
| this.nullableAccessor = nullableAccessor; |
| isSetReader = new UInt1ColumnReader(); |
| isSetReader.bindVector(null, |
| VectorAccessors.nullableBitsAccessor(nullableAccessor)); |
| isSetReader.bindNullState(REQUIRED_STATE_READER); |
| } |
| |
| @Override |
| public void bindIndex(ColumnReaderIndex rowIndex) { |
| nullableAccessor.bind(rowIndex); |
| isSetReader.bindIndex(rowIndex); |
| } |
| |
| @Override |
| public boolean isNull() { |
| return isSetReader.getInt() == 0; |
| } |
| } |
| |
| /** |
| * Holder for the NullableVector wrapper around a bits vector and a |
| * data vector. Manages the bits vector to extract the nullability |
| * value. |
| * <p> |
| * This class allows the same reader to handle both the required and |
| * nullable cases; the only difference is how nulls are handled. |
| */ |
| |
| protected static class ListIsSetVectorStateReader implements NullStateReader { |
| |
| private final VectorAccessor bitsAccessor; |
| private final UInt1ColumnReader isSetReader; |
| |
| public ListIsSetVectorStateReader(VectorAccessor bitsAccessor) { |
| this.bitsAccessor = bitsAccessor; |
| isSetReader = new UInt1ColumnReader(); |
| isSetReader.bindVector(null, bitsAccessor); |
| isSetReader.bindNullState(REQUIRED_STATE_READER); |
| } |
| |
| @Override |
| public void bindIndex(ColumnReaderIndex rowIndex) { |
| bitsAccessor.bind(rowIndex); |
| isSetReader.bindIndex(rowIndex); |
| } |
| |
| @Override |
| public boolean isNull() { |
| return isSetReader.getInt() == 0; |
| } |
| } |
| |
| /** |
| * Null state that handles the strange union semantics that both |
| * the union and the values can be null. A value is null if either |
| * the union or the value is null. (Though, presumably, in the normal |
| * case either the union is null or one of the associated values is |
| * null.) |
| */ |
| |
| protected static class MemberNullStateReader implements NullStateReader { |
| |
| private final NullStateReader unionNullState; |
| private final NullStateReader memberNullState; |
| |
| public MemberNullStateReader(NullStateReader unionNullState, NullStateReader memberNullState) { |
| this.unionNullState = unionNullState; |
| this.memberNullState = memberNullState; |
| } |
| |
| @Override |
| public void bindIndex(ColumnReaderIndex rowIndex) { |
| memberNullState.bindIndex(rowIndex); |
| } |
| |
| @Override |
| public boolean isNull() { |
| return unionNullState.isNull() || memberNullState.isNull(); |
| } |
| } |
| |
| /** |
| * Handle the awkward situation with complex types. They don't carry their own |
| * bits (null state) vector. Instead, we define them as null if the type of |
| * the union is other than the type of the map or list. (Since the same vector |
| * that holds state also holds the is-null value, this check includes the |
| * check if the entire union is null.) |
| */ |
| |
| protected static class ComplexMemberStateReader implements NullStateReader { |
| |
| private UInt1ColumnReader typeReader; |
| private MinorType type; |
| |
| public ComplexMemberStateReader(UInt1ColumnReader typeReader, MinorType type) { |
| this.typeReader = typeReader; |
| this.type = type; |
| } |
| |
| @Override |
| public void bindIndex(ColumnReaderIndex rowIndex) { } |
| |
| @Override |
| public boolean isNull() { |
| return typeReader.getInt() != type.getNumber(); |
| } |
| } |
| |
| /** |
| * Extract null state from the union vector's type vector. The union reader |
| * manages the type reader, so no binding is done here. |
| */ |
| |
| protected static class TypeVectorStateReader implements NullStateReader { |
| |
| public final UInt1ColumnReader typeReader; |
| |
| public TypeVectorStateReader(UInt1ColumnReader typeReader) { |
| this.typeReader = typeReader; |
| } |
| |
| @Override |
| public void bindIndex(ColumnReaderIndex rowIndex) { |
| typeReader.bindIndex(rowIndex); |
| } |
| |
| @Override |
| public boolean isNull() { |
| return typeReader.getInt() == UnionVector.NULL_MARKER; |
| } |
| } |
| |
| protected static class AlwaysNullStateReader implements NullStateReader { |
| |
| @Override |
| public void bindIndex(ColumnReaderIndex rowIndex) { |
| } |
| |
| @Override |
| public boolean isNull() { |
| return true; |
| } |
| } |
| } |