LakshSingla commented on code in PR #14900: URL: https://github.com/apache/druid/pull/14900#discussion_r1344741588
########## processing/src/main/java/org/apache/druid/frame/field/NumericFieldWriter.java: ########## @@ -0,0 +1,137 @@ +/* + * 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.druid.frame.field; + +import org.apache.datasketches.memory.WritableMemory; +import org.apache.druid.segment.BaseNullableColumnValueSelector; + +/** + * FieldWriter for numeric datatypes. The parent class does the null handling for the underlying data, while + * the individual subclasses write the individual element (long, float or double type). This also allows for a clean + * reuse of the readers and writers between the numeric types and also allowing the array writers ({@link NumericArrayFieldWriter}) + * to use these methods directly without duplication + * + * Format: + * - 1 byte: Whether the following value is null or not. Take a look at the note on the indicator bytes. + * - X bytes: Encoded value of the selector, or the default value if it is null. X denotes the size of the numeric value + * + * Indicator bytes for denoting whether the element is null or not null changes depending on whether the writer is used + * to write the data for individual value (like LONG) or for an element of an array (like ARRAY<LONG>). This is because + * array support for the numeric types was added later and by then the field writers for individual fields were using + * 0x00 to denote the null byte, which is reserved for denoting the array end when we are writing the elements as part + * of the array instead. (0x00 is used for array end because it helps in preserving the byte comparison property of the + * numeric array field writers). + * + * Therefore, to preserve backward and forward compatibility, the individual element's writers were left unchanged, Review Comment: 1. There is format in the JavaDoc above 2. There is an explanation about the choice of the bytes chosen here 3. Added @see to the `NumericArrayFieldWriter` which contains the info on how this field writer is used for array elements. Is there anything specific that I am missing here, that would help with clarification? -- 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. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
