org.apache.kafka.streams.kstream.internals.KStreamFlatTransform 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
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* 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.streams.KeyValue;
import org.apache.kafka.streams.kstream.Transformer;
import org.apache.kafka.streams.kstream.TransformerSupplier;
import org.apache.kafka.streams.processor.api.ContextualProcessor;
import org.apache.kafka.streams.processor.api.Processor;
import org.apache.kafka.streams.processor.api.ProcessorContext;
import org.apache.kafka.streams.processor.api.ProcessorSupplier;
import org.apache.kafka.streams.processor.api.Record;
import org.apache.kafka.streams.processor.internals.InternalProcessorContext;
import org.apache.kafka.streams.state.StoreBuilder;
import java.util.Set;
public class KStreamFlatTransform implements ProcessorSupplier {
private final TransformerSupplier>> transformerSupplier;
public KStreamFlatTransform(final TransformerSupplier>> transformerSupplier) {
this.transformerSupplier = transformerSupplier;
}
@Override
public Processor get() {
return new KStreamFlatTransformProcessor<>(transformerSupplier.get());
}
@Override
public Set> stores() {
return transformerSupplier.stores();
}
public static class KStreamFlatTransformProcessor extends ContextualProcessor {
private final Transformer>> transformer;
public KStreamFlatTransformProcessor(final Transformer>> transformer) {
this.transformer = transformer;
}
@Override
public void init(final ProcessorContext context) {
super.init(context);
transformer.init((InternalProcessorContext) context);
}
@Override
public void process(final Record record) {
final Iterable> pairs = transformer.transform(record.key(), record.value());
if (pairs != null) {
for (final KeyValue pair : pairs) {
context().forward(record.withKey(pair.key).withValue(pair.value));
}
}
}
@Override
public void close() {
transformer.close();
}
}
}