org.apache.kafka.streams.kstream.internals.KStreamFlatMap Maven / Gradle / Ivy
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* 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,
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* See the License for the specific language governing permissions and
* limitations under the License.
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package org.apache.kafka.streams.kstream.internals;
import org.apache.kafka.streams.KeyValue;
import org.apache.kafka.streams.kstream.KeyValueMapper;
import org.apache.kafka.streams.processor.api.ContextualProcessor;
import org.apache.kafka.streams.processor.api.Processor;
import org.apache.kafka.streams.processor.api.ProcessorSupplier;
import org.apache.kafka.streams.processor.api.Record;
import java.util.Objects;
class KStreamFlatMap implements ProcessorSupplier {
private final KeyValueMapper>> mapper;
KStreamFlatMap(final KeyValueMapper>> mapper) {
this.mapper = mapper;
}
@Override
public Processor get() {
return new KStreamFlatMapProcessor();
}
private class KStreamFlatMapProcessor extends ContextualProcessor {
@Override
public void process(final Record record) {
final Iterable> newKeyValues =
mapper.apply(record.key(), record.value());
Objects.requireNonNull(newKeyValues, "The provided KeyValueMapper returned null which is not allowed.");
for (final KeyValue newPair : newKeyValues) {
context().forward(record.withKey(newPair.key).withValue(newPair.value));
}
}
}
}