content: /*
   * 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.processor;
  
  import org.apache.kafka.clients.consumer.ConsumerRecord;
  import org.apache.kafka.streams.kstream.KTable;
  
  /**
   * An interface that allows the Kafka Streams framework to extract a timestamp from an instance of {@link ConsumerRecord}.
   * The extracted timestamp is defined as milliseconds.
   */
  @FunctionalInterface
  public interface TimestampExtractor {
  
      /**
       * Extracts a timestamp from a record. The timestamp must be positive to be considered a valid timestamp.
       * Returning a negative timestamp will cause the record not to be processed but rather silently skipped.
       * In case the record contains a negative timestamp and this is considered a fatal error for the application,
       * throwing a {@link RuntimeException} instead of returning the timestamp is a valid option too.
       * For this case, Streams will stop processing and shut down to allow you investigate in the root cause of the
       * negative timestamp.
       * <p>
       * The timestamp extractor implementation must be stateless.
       * <p>
       * The extracted timestamp MUST represent the milliseconds since midnight, January 1, 1970 UTC.
       * <p>
       * It is important to note that this timestamp may become the message timestamp for any messages sent to changelogs
       * updated by {@link KTable}s and joins.
       * The message timestamp is used for log retention and log rolling, so using nonsensical values may result in
       * excessive log rolling and therefore broker performance degradation.
       *
       *
       * @param record a data record
       * @param partitionTime the highest extracted valid timestamp of the current record's partition˙ (could be -1 if unknown)
       * @return the timestamp of the record
       */
      long extract(ConsumerRecord<Object, Object> record, long partitionTime);
  }
  