yupeng9 commented on a change in pull request #6845: URL: https://github.com/apache/incubator-pinot/pull/6845#discussion_r629575024
########## File path: pinot-segment-local/src/main/java/org/apache/pinot/segment/local/recordtransformer/ComplexTypeTransformer.java ########## @@ -0,0 +1,229 @@ +/** + * 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.pinot.segment.local.recordtransformer; + +import com.google.common.annotations.VisibleForTesting; +import java.util.ArrayList; +import java.util.Collection; +import java.util.Collections; +import java.util.HashSet; +import java.util.List; +import java.util.Map; +import javax.annotation.Nullable; +import org.apache.pinot.spi.config.table.TableConfig; +import org.apache.pinot.spi.config.table.ingestion.ComplexTypeConfig; +import org.apache.pinot.spi.data.readers.GenericRow; + + +/** + * A transformer to handle the complex types such as Map and Collection, with flattening and unnesting. + * <p> + * The map flattening rule will recursively flatten all the map types, except for those under the collection that is not marked as to unnest. + * + * For example: + * <pre> + * { + * "t1":{ + * "array":[ + * { + * "t2":{ + * "a":"v1" + * } + * } + * ] + * } + * } + * </pre> + * + * flattens to + * <pre> + * { + * "t1.array":[ + * { + * "t2.a":"v1" + * } + * ] + * } + * <pre/> + * + * <p> + * + * The unnesting rule will flatten all the collections provided, which are the paths navigating to the collections. For + * the same example above. If the the collectionToUnnest is provided as "t1.array", then the rule will unnest the + * previous output to: + * + * <pre> + * [{ + * "t1.arrayt2.a": "v1", + * }] + * * <pre/> + * + * Note the unnest rule will output a collection of generic rows under the field {@link GenericRow#MULTIPLE_RECORDS_KEY}. + * + */ +public class ComplexTypeTransformer implements RecordTransformer { + private static final CharSequence DELIMITER = "."; + private final List<String> _collectionsToUnnest; + + public ComplexTypeTransformer(TableConfig tableConfig) { Review comment: Yes, this is planned to be addressed in a following PR as mentioned in the PR description -- 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 --------------------------------------------------------------------- To unsubscribe, e-mail: commits-unsubscr...@pinot.apache.org For additional commands, e-mail: commits-h...@pinot.apache.org
