KazydubB commented on a change in pull request #1870: DRILL-7359: Add support for DICT type in RowSet Framework URL: https://github.com/apache/drill/pull/1870#discussion_r348485350
########## File path: exec/vector/src/main/java/org/apache/drill/exec/vector/accessor/reader/NullReader.java ########## @@ -0,0 +1,377 @@ +/* + * 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; +import org.apache.drill.exec.record.metadata.ColumnMetadata; +import org.apache.drill.exec.record.metadata.TupleMetadata; +import org.apache.drill.exec.record.metadata.VariantMetadata; +import org.apache.drill.exec.vector.accessor.ArrayReader; +import org.apache.drill.exec.vector.accessor.DictReader; +import org.apache.drill.exec.vector.accessor.ObjectReader; +import org.apache.drill.exec.vector.accessor.ObjectType; +import org.apache.drill.exec.vector.accessor.ScalarReader; +import org.apache.drill.exec.vector.accessor.TupleReader; +import org.apache.drill.exec.vector.accessor.ValueType; +import org.apache.drill.exec.vector.accessor.VariantReader; +import org.joda.time.Instant; +import org.joda.time.LocalDate; +import org.joda.time.LocalTime; +import org.joda.time.Period; + +import java.math.BigDecimal; + +/** + * Dummy reader which returns {@code null} on access to getters for scalar types + * ({@link #getString()}, {@link #getBytes()} etc.) and itself on access to reader types + * ({@link #scalar()}, {@link #tuple()} etc.). Used when accessing {@link DictReader} by non-existent key. + * {@link #isNull()} returns {@code true}. + * + * Does not preserve metadata structure. Other methods throw {@link UnsupportedOperationException}. todo: + * + * @see DictReader + */ +public class NullReader implements ScalarReader, ArrayReader, TupleReader, VariantReader, ObjectReader, DictReader { + + private static final NullReader INSTANCE = new NullReader(); + + public static NullReader instance() { + return INSTANCE; + } + + @Override + public int size() { + notSupported("size()"); + return 0; + } + + @Override + public ObjectType entryType() { + notSupported("entryType()"); + return null; + } + + @Override + public ObjectReader entry() { + notSupported("entry()"); + return null; + } + + @Override + public ScalarReader scalar() { + return this; + } + + @Override + public TupleReader tuple() { + return this; + } + + @Override + public ArrayReader array() { + return this; + } + + @Override + public VariantReader variant() { + return this; + } + + @Override + public DictReader dict() { + return this; + } + + @Override + public void setPosn(int index) { + notSupported("setPosn(int)"); + } + + @Override + public void rewind() { + notSupported("rewind()"); + } + + @Override + public boolean next() { + return false; + } + + @Override + public ValueType valueType() { + notSupported("valueType()"); + return null; + } + + @Override + public ValueType extendedType() { + notSupported("extendedType()"); + return null; + } + + @Override + public int getInt() { + notSupported("getInt()"); + return 0; + } + + @Override + public boolean getBoolean() { + notSupported("getBoolean()"); + return false; + } + + @Override + public long getLong() { + notSupported("getLong()"); + return 0; + } + + @Override + public double getDouble() { + notSupported("getDouble()"); + return 0; + } + + @Override + public String getString() { + return null; + } + + @Override + public byte[] getBytes() { + return null; + } + + @Override + public BigDecimal getDecimal() { + return null; + } + + @Override + public Period getPeriod() { + return null; + } + + @Override + public LocalDate getDate() { + return null; + } + + @Override + public LocalTime getTime() { + return null; + } + + @Override + public Instant getTimestamp() { + return null; + } + + @Override + public Object getValue() { + return null; + } + + @Override + public TupleMetadata tupleSchema() { + notSupported("tupleSchema()"); + return null; + } + + @Override + public int columnCount() { + notSupported("columnCount()"); + return 0; + } + + @Override + public ObjectReader column(int colIndex) { + notSupported("column(int)"); + return null; + } + + @Override + public ObjectReader column(String colName) { + notSupported("column(String)"); + return null; + } + + @Override + public ObjectType type(int colIndex) { + notSupported("type(int)"); + return null; + } + + @Override + public ObjectType type(String colName) { + notSupported("type(String)"); + return null; + } + + @Override + public ScalarReader scalar(int colIndex) { + notSupported("scalar(int)"); + return null; + } + + @Override + public ScalarReader scalar(String colName) { + notSupported("scalar(String)"); + return null; + } + + @Override + public TupleReader tuple(int colIndex) { + notSupported("tuple(int)"); + return null; + } + + @Override + public TupleReader tuple(String colName) { + notSupported("tuple(String)"); + return null; + } + + @Override + public ArrayReader array(int colIndex) { + notSupported("array(int)"); + return null; + } + + @Override + public ArrayReader array(String colName) { + notSupported("array(String)"); + return null; + } + + @Override + public VariantReader variant(int colIndex) { + notSupported("variant(int)"); + return null; + } + + @Override + public VariantReader variant(String colName) { + notSupported("variant(String)"); + return null; + } + + @Override + public DictReader dict(int colIndex) { + notSupported("dict(int)"); + return null; + } + + @Override + public DictReader dict(String colName) { + notSupported("dict(String)"); + return null; + } + + @Override + public VariantMetadata variantSchema() { + notSupported("variantSchema()"); + return null; + } + + @Override + public boolean hasType(TypeProtos.MinorType type) { + notSupported("hasType(TypeProtos.MinorType)"); + return false; + } + + @Override + public ObjectReader member(TypeProtos.MinorType type) { + notSupported("member(TypeProtos.MinorType)"); + return null; + } + + @Override + public ScalarReader scalar(TypeProtos.MinorType type) { + notSupported("scalar(TypeProtos.MinorType)"); + return null; + } + + @Override + public TypeProtos.MinorType dataType() { + notSupported("dataType()"); + return null; + } + + @Override + public ObjectReader member() { + notSupported("member()"); + return null; + } + + @Override + public ColumnMetadata schema() { + notSupported("schema()"); + return null; + } + + @Override + public ObjectType type() { + notSupported("type()"); + return null; + } + + @Override + public boolean isNull() { + return true; + } + + @Override + public Object getObject() { + return null; + } + + @Override + public String getAsString() { + return "null"; + } + + @Override + public ObjectReader getValueReader(Object key) { + notSupported("getValueReader(Object)"); + return null; + } + + @Override + public Object get(Object key) { + notSupported("get(Object)"); + return null; + } + + @Override + public ValueType keyColumnType() { + notSupported("keyColumnType()"); + return null; + } + + @Override + public ObjectType valueColumnType() { + notSupported("valueColumnType()"); + return null; + } + + private void notSupported(String methodName) { + throw new UnsupportedOperationException(methodName + " is not supported in NullReader"); + } Review comment: I know this, but there is a need to `throw` and current form contains `throw` part. On the other hand, the form you are proposing proposes (somewhat) better code readability and there is no need to write `return`s all the time. Will change. ---------------------------------------------------------------- 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. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services
