rdblue commented on a change in pull request #1096: URL: https://github.com/apache/iceberg/pull/1096#discussion_r436035765
########## File path: flink/src/main/java/org/apache/iceberg/flink/FlinkTypeVisitor.java ########## @@ -0,0 +1,79 @@ +/* + * 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.flink; + +import java.util.LinkedHashMap; +import java.util.Map; +import org.apache.flink.api.java.tuple.Tuple2; +import org.apache.flink.table.types.AtomicDataType; +import org.apache.flink.table.types.CollectionDataType; +import org.apache.flink.table.types.DataType; +import org.apache.flink.table.types.FieldsDataType; +import org.apache.flink.table.types.KeyValueDataType; +import org.apache.flink.table.types.logical.RowType; + +public class FlinkTypeVisitor<T> { + + static <T> T visit(DataType dataType, FlinkTypeVisitor<T> visitor) { + if (dataType instanceof FieldsDataType) { + FieldsDataType fieldsType = (FieldsDataType) dataType; + Map<String, DataType> fields = fieldsType.getFieldDataTypes(); + Map<String, Tuple2<String, T>> fieldResults = new LinkedHashMap<>(); + // Make sure that we're traversing the fields in the same order as constructing the schema's fields. + RowType rowType = (RowType) dataType.getLogicalType(); + for (int i = 0; i < fields.size(); i++) { + String name = rowType.getFieldNames().get(i); + String comment = rowType.getFields().get(i).getDescription().orElse(null); + fieldResults.put(name, Tuple2.of(comment, visit(fields.get(name), visitor))); + } + return visitor.fields(fieldsType, fieldResults); + } else if (dataType instanceof CollectionDataType) { + CollectionDataType collectionType = (CollectionDataType) dataType; + return visitor.collection(collectionType, + visit(collectionType.getElementDataType(), visitor)); + } else if (dataType instanceof KeyValueDataType) { + KeyValueDataType mapType = (KeyValueDataType) dataType; + return visitor.map(mapType, + visit(mapType.getKeyDataType(), visitor), + visit(mapType.getValueDataType(), visitor)); + } else if (dataType instanceof AtomicDataType) { + AtomicDataType atomic = (AtomicDataType) dataType; + return visitor.atomic(atomic); + } else { + throw new UnsupportedOperationException("Unsupported data type: " + dataType); + } + } + + public T fields(FieldsDataType dataType, Map<String, Tuple2<String, T>> fieldResults) { Review comment: If `fields` is always a row, it seems to me that `row` might be a better name because it is more clear that it is a record/struct/tuple type. It wasn't clear to me that `fields` was the record type, since most other formats make a distinction between a record and its field list. ---------------------------------------------------------------- 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]
