org.apache.kafka.streams.kstream.internals.KStreamJoinWindow 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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* limitations under the License.
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package org.apache.kafka.streams.kstream.internals;
import org.apache.kafka.streams.processor.AbstractProcessor;
import org.apache.kafka.streams.processor.Processor;
import org.apache.kafka.streams.processor.ProcessorContext;
import org.apache.kafka.streams.processor.ProcessorSupplier;
import org.apache.kafka.streams.state.WindowStore;
class KStreamJoinWindow implements ProcessorSupplier {
private final String windowName;
KStreamJoinWindow(final String windowName) {
this.windowName = windowName;
}
@Override
public Processor get() {
return new KStreamJoinWindowProcessor();
}
private class KStreamJoinWindowProcessor extends AbstractProcessor {
private WindowStore window;
@SuppressWarnings("unchecked")
@Override
public void init(final ProcessorContext context) {
super.init(context);
window = (WindowStore) context.getStateStore(windowName);
}
@Override
public void process(final K key, final V value) {
// if the key is null, we do not need to put the record into window store
// since it will never be considered for join operations
if (key != null) {
context().forward(key, value);
// Every record basically starts a new window. We're using a window store mostly for the retention.
window.put(key, value, context().timestamp());
}
}
}
}