timsants commented on a change in pull request #6046: URL: https://github.com/apache/incubator-pinot/pull/6046#discussion_r506046635
########## File path: pinot-spi/src/main/java/org/apache/pinot/spi/data/readers/BaseRecordExtractor.java ########## @@ -0,0 +1,190 @@ +/** + * 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.spi.data.readers; + +import java.nio.ByteBuffer; +import java.util.Arrays; +import java.util.Collection; +import java.util.HashMap; +import java.util.Map; +import javax.annotation.Nullable; + + +/** + * Base abstract class for extracting and converting the fields of various data formats into supported Pinot data types. + * + * @param <T> the format of the input record + */ +public abstract class BaseRecordExtractor<T> implements RecordExtractor<T> { + + /** + * Converts the field value to either a single value (string, number, byte[]), multi value (Object[]) or a Map. + * Returns {@code null} if the value is an empty array/collection/map. + * + * Natively Pinot only understands single values and multi values. + * Map is useful only if some ingestion transform functions operates on it in the transformation layer. + */ + @Nullable + public Object convert(Object value) { + Object convertedValue; + if (isMultiValue(value)) { + convertedValue = convertMultiValue(value); + } else if (isMap(value)) { + convertedValue = convertMap(value); + } else if (isRecord(value)) { + convertedValue = convertRecord(value); + } else { + convertedValue = convertSingleValue(value); + } + return convertedValue; + } + + /** + * Returns whether the object is of the data format's base type. Override this method if the extractor + * can handle the conversion of nested record types. + */ + protected boolean isRecord(Object value) { + return false; + } + + /** + * Returns whether the object is of a multi-value type. Override this method if the data format represents + * multi-value objects differently. + */ + protected boolean isMultiValue(Object value) { + return value instanceof Collection; + } + + /** + * Returns whether the object is of a map type. Override this method if the data format represents map objects + * differently. + */ + protected boolean isMap(Object value) { + return value instanceof Map; + } + + /** + * Handles the conversion of every field of the object for the particular data format. Override this method if the + * extractor can convert nested record types. + * + * @param value should be verified to be a record type prior to calling this method as it will be handled with this + * assumption + */ + @Nullable + protected Object convertRecord(Object value) { + throw new UnsupportedOperationException("Extractor cannot convert record type structures for this data format."); + } + + /** + * Handles the conversion of each element of a multi-value object. Returns {@code null} if the field value is + * {@code null}. + * + * This implementation converts the Collection to an Object array. Override this method if the data format + * requires a different conversion for its multi-value objects. + * + * @param value should be verified to be a Collection type prior to calling this method as it will be casted + * to a Collection without checking + */ + @Nullable + protected Object convertMultiValue(Object value) { + Collection collection = (Collection) value; + if (collection.isEmpty()) { + return null; + } + + int numValues = collection.size(); + Object[] array = new Object[numValues]; + int index = 0; + for (Object element : collection) { + Object convertedValue = null; + if (element != null) { + convertedValue = convert(element); + } + if (convertedValue != null && !convertedValue.toString().equals("")) { Review comment: I'll mention this nuance in the method's javadoc. ---------------------------------------------------------------- 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
