org.apache.kafka.streams.kstream.internals.StreamStreamJoinUtil Maven / Gradle / Ivy
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* 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,
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package org.apache.kafka.streams.kstream.internals;
import org.apache.kafka.common.metrics.Sensor;
import org.apache.kafka.streams.processor.api.ProcessorContext;
import org.apache.kafka.streams.processor.api.Record;
import org.apache.kafka.streams.processor.api.RecordMetadata;
import org.slf4j.Logger;
public final class StreamStreamJoinUtil {
private StreamStreamJoinUtil(){
}
public static boolean skipRecord(
final Record record, final Logger logger,
final Sensor droppedRecordsSensor,
final ProcessorContext context) {
// we do join iff keys are equal, thus, if key is null we cannot join and just ignore the record
//
// we also ignore the record if value is null, because in a key-value data model a null-value indicates
// an empty message (ie, there is nothing to be joined) -- this contrast SQL NULL semantics
// furthermore, on left/outer joins 'null' in ValueJoiner#apply() indicates a missing record --
// thus, to be consistent and to avoid ambiguous null semantics, null values are ignored
if (record.key() == null || record.value() == null) {
if (context.recordMetadata().isPresent()) {
final RecordMetadata recordMetadata = context.recordMetadata().get();
logger.warn(
"Skipping record due to null key or value. "
+ "topic=[{}] partition=[{}] offset=[{}]",
recordMetadata.topic(), recordMetadata.partition(), recordMetadata.offset()
);
} else {
logger.warn(
"Skipping record due to null key or value. Topic, partition, and offset not known."
);
}
droppedRecordsSensor.record();
return true;
} else {
return false;
}
}
}