/*
* 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.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.KeyValueStore;
public class KTableSource<K, V> implements ProcessorSupplier<K, V> {
public final String storeName;
private boolean sendOldValues = false;
public KTableSource(String storeName) {
this.storeName = storeName;
}
@Override
public Processor<K, V> get() {
return new KTableSourceProcessor();
}
public void enableSendingOldValues() {
sendOldValues = true;
}
private class KTableSourceProcessor extends AbstractProcessor<K, V> {
private KeyValueStore<K, V> store;
private TupleForwarder<K, V> tupleForwarder;
@SuppressWarnings("unchecked")
@Override
public void init(ProcessorContext context) {
super.init(context);
store = (KeyValueStore<K, V>) context.getStateStore(storeName);
tupleForwarder = new TupleForwarder<>(store, context, new ForwardingCacheFlushListener<K, V>(context, sendOldValues), sendOldValues);
}
@Override
public void process(K key, V value) {
// if the key is null, then ignore the record
if (key == null)
return;
V oldValue = store.get(key);
store.put(key, value);
tupleForwarder.maybeForward(key, value, oldValue);
}
}
}