frankvicky commented on code in PR #21408: URL: https://github.com/apache/kafka/pull/21408#discussion_r2770205073
########## streams/src/main/java/org/apache/kafka/streams/state/ValueTimestampHeaders.java: ########## @@ -0,0 +1,168 @@ +/* + * 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.kafka.streams.state; + +import org.apache.kafka.common.header.Headers; +import org.apache.kafka.common.header.internals.RecordHeaders; +import org.apache.kafka.streams.state.internals.HeadersDeserializer; + +import java.util.Objects; + +/** + * Combines a value with its timestamp and associated record headers. + * + * @param <V> the value type + */ +public final class ValueTimestampHeaders<V> { + + private final V value; + private final long timestamp; + private Headers headers; + private final byte[] rawHeaders; + + private ValueTimestampHeaders(final V value, final long timestamp, final Headers headers) { + this.value = value; + this.timestamp = timestamp; + this.headers = headers == null ? new RecordHeaders() : headers; + this.rawHeaders = null; + } + + private ValueTimestampHeaders(final V value, final long timestamp, final byte[] rawHeaders) { + this.value = value; + this.timestamp = timestamp; + this.headers = null; + this.rawHeaders = rawHeaders; + } + + /** + * Create a new {@link ValueTimestampHeaders} instance if the provided {@code value} is not {@code null}. + * + * @param value the value + * @param timestamp the timestamp + * @param headers the headers (may be {@code null}, treated as empty) + * @param <V> the type of the value + * @return a new {@link ValueTimestampHeaders} instance if the provided {@code value} is not {@code null}; + * otherwise {@code null} is returned + */ + public static <V> ValueTimestampHeaders<V> make(final V value, + final long timestamp, + final Headers headers) { + if (value == null) { + return null; + } + return new ValueTimestampHeaders<>(value, timestamp, headers); + } + + /** + * Create a new {@link ValueTimestampHeaders} instance. + * The provided {@code value} may be {@code null}. + * + * @param value the value (may be {@code null}) + * @param timestamp the timestamp + * @param headers the headers (may be {@code null}, treated as empty) + * @param <V> the type of the value + * @return a new {@link ValueTimestampHeaders} instance + */ + public static <V> ValueTimestampHeaders<V> makeAllowNullable(final V value, + final long timestamp, + final Headers headers) { + return new ValueTimestampHeaders<>(value, timestamp, headers); + } + + /** + * Return the wrapped {@code value} of the given {@code valueTimestampHeaders} parameter + * if the parameter is not {@code null}. + * + * @param valueTimestampHeaders a {@link ValueTimestampHeaders} instance; can be {@code null} + * @param <V> the type of the value + * @return the wrapped {@code value} of {@code valueTimestampHeaders} if not {@code null}; otherwise {@code null} + */ + public static <V> V getValueOrNull(final ValueTimestampHeaders<V> valueTimestampHeaders) { + return valueTimestampHeaders == null ? null : valueTimestampHeaders.value; + } + + /** + * <strong>Internal use only.</strong> This method is used by the deserialization infrastructure + * and should not be called directly by application code. + * <p> + * Create a new {@link ValueTimestampHeaders} instance with raw (serialized) headers for lazy deserialization. + * The headers will be deserialized lazily when {@link #headers()} is first called, minimizing overhead + * during range scans when headers are not accessed. + * <p> + * This method is used internally by {@link org.apache.kafka.streams.state.internals.ValueTimestampHeadersDeserializer}. + * + * @param value the value + * @param timestamp the timestamp + * @param rawHeaders the serialized headers bytes + * @param <V> the type of the value + * @return a new {@link ValueTimestampHeaders} instance if the provided {@code value} is not {@code null}; + * otherwise {@code null} is returned + */ + public static <V> ValueTimestampHeaders<V> makeWithRawHeaders(final V value, + final long timestamp, + final byte[] rawHeaders) { + if (value == null) { + return null; + } + return new ValueTimestampHeaders<>(value, timestamp, rawHeaders); + } + + public V value() { + return value; + } + + public long timestamp() { + return timestamp; + } + + public Headers headers() { + if (headers == null && rawHeaders != null) { + headers = HeadersDeserializer.deserialize(rawHeaders); + } + return headers != null ? headers : new RecordHeaders(); Review Comment: Nice catch -- This is an automated message from the Apache Git Service. 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