rdblue commented on a change in pull request #830: URL: https://github.com/apache/iceberg/pull/830#discussion_r441027247
########## File path: parquet/src/main/java/org/apache/iceberg/parquet/ApplyNameMapping.java ########## @@ -0,0 +1,106 @@ +/* + * 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.iceberg.parquet; + +import java.util.List; +import java.util.Objects; +import java.util.stream.Collectors; +import org.apache.iceberg.mapping.MappedField; +import org.apache.iceberg.mapping.NameMapping; +import org.apache.parquet.Preconditions; +import org.apache.parquet.schema.GroupType; +import org.apache.parquet.schema.MessageType; +import org.apache.parquet.schema.PrimitiveType; +import org.apache.parquet.schema.Type; +import org.apache.parquet.schema.Types; + +class ApplyNameMapping extends ParquetTypeVisitor<Type> { + private final NameMapping nameMapping; + + ApplyNameMapping(NameMapping nameMapping) { + this.nameMapping = nameMapping; + } + + @Override + public Type message(MessageType message, List<Type> fields) { + Types.MessageTypeBuilder builder = org.apache.parquet.schema.Types.buildMessage(); + fields.stream().filter(Objects::nonNull).forEach(builder::addField); + + return builder.named(message.getName()); + } + + @Override + public Type struct(GroupType struct, List<Type> types) { + MappedField field = nameMapping.find(currentPath()); + List<Type> actualTypes = types.stream().filter(Objects::nonNull).collect(Collectors.toList()); + Type structType = struct.withNewFields(actualTypes); + + return field == null ? structType : structType.withId(field.id()); + } + + @Override + public Type list(GroupType list, Type elementType) { + Preconditions.checkArgument(elementType != null, + "List type must have element field"); + + MappedField field = nameMapping.find(currentPath()); + Type listType = org.apache.parquet.schema.Types.list(list.getRepetition()) + .element(elementType) + .named(list.getName()); + + return field == null ? listType : listType.withId(field.id()); + } + + @Override + public Type map(GroupType map, Type keyType, Type valueType) { + Preconditions.checkArgument(keyType != null && valueType != null, + "Map type must have both key field and value field"); + + MappedField field = nameMapping.find(currentPath()); + Type mapType = org.apache.parquet.schema.Types.map(map.getRepetition()) + .key(keyType) + .value(valueType) + .named(map.getName()); + + return field == null ? mapType : mapType.withId(field.id()); + } + + @Override + public Type primitive(PrimitiveType primitive) { + MappedField field = nameMapping.find(currentPath()); + return field == null ? primitive : primitive.withId(field.id()); + } + + @Override + public void beforeRepeatedElement(Type element) { + } Review comment: Can you add comments to these methods to explain why they are here? ---------------------------------------------------------------- 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: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
