org.apache.kafka.streams.kstream.internals.SessionTupleForwarder 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,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.kafka.streams.kstream.internals;
import org.apache.kafka.streams.kstream.Windowed;
import org.apache.kafka.streams.processor.ProcessorContext;
import org.apache.kafka.streams.processor.StateStore;
import org.apache.kafka.streams.processor.To;
import org.apache.kafka.streams.state.internals.CacheFlushListener;
import org.apache.kafka.streams.state.internals.WrappedStateStore;
/**
* This class is used to determine if a processor should forward values to child nodes.
* Forwarding by this class only occurs when caching is not enabled. If caching is enabled,
* forwarding occurs in the flush listener when the cached store flushes.
*
* @param
* @param
*/
class SessionTupleForwarder {
private final ProcessorContext context;
private final boolean sendOldValues;
private final boolean cachingEnabled;
@SuppressWarnings("unchecked")
SessionTupleForwarder(final StateStore store,
final ProcessorContext context,
final CacheFlushListener, V> flushListener,
final boolean sendOldValues) {
this.context = context;
this.sendOldValues = sendOldValues;
cachingEnabled = ((WrappedStateStore) store).setFlushListener(flushListener, sendOldValues);
}
public void maybeForward(final Windowed key,
final V newValue,
final V oldValue) {
if (!cachingEnabled) {
context.forward(key, new Change<>(newValue, sendOldValues ? oldValue : null), To.all().withTimestamp(key.window().end()));
}
}
}