org.apache.kafka.streams.processor.TimestampExtractor Maven / Gradle / Ivy
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* http://www.apache.org/licenses/LICENSE-2.0
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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.
*/
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.
*
* The timestamp extractor implementation must be stateless.
*
* The extracted timestamp MUST represent the milliseconds since midnight, January 1, 1970 UTC.
*
* 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 record, long partitionTime);
}