| /** |
| * 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.Aggregator; |
| import org.apache.kafka.streams.KeyValue; |
| import org.apache.kafka.streams.kstream.Initializer; |
| import org.apache.kafka.streams.kstream.Window; |
| import org.apache.kafka.streams.kstream.Windowed; |
| import org.apache.kafka.streams.kstream.Windows; |
| 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.state.WindowStore; |
| import org.apache.kafka.streams.state.WindowStoreIterator; |
| |
| import java.util.Iterator; |
| import java.util.Map; |
| |
| public class KStreamWindowAggregate<K, V, T, W extends Window> implements KStreamAggProcessorSupplier<K, Windowed<K>, V, T> { |
| |
| private final String storeName; |
| private final Windows<W> windows; |
| private final Initializer<T> initializer; |
| private final Aggregator<K, V, T> aggregator; |
| |
| private boolean sendOldValues = false; |
| |
| public KStreamWindowAggregate(Windows<W> windows, String storeName, Initializer<T> initializer, Aggregator<K, V, T> aggregator) { |
| this.windows = windows; |
| this.storeName = storeName; |
| this.initializer = initializer; |
| this.aggregator = aggregator; |
| } |
| |
| @Override |
| public Processor<K, V> get() { |
| return new KStreamWindowAggregateProcessor(); |
| } |
| |
| @Override |
| public void enableSendingOldValues() { |
| sendOldValues = true; |
| } |
| |
| private class KStreamWindowAggregateProcessor extends AbstractProcessor<K, V> { |
| |
| private WindowStore<K, T> windowStore; |
| |
| @SuppressWarnings("unchecked") |
| @Override |
| public void init(ProcessorContext context) { |
| super.init(context); |
| |
| windowStore = (WindowStore<K, T>) context.getStateStore(storeName); |
| } |
| |
| @Override |
| public void process(K key, V value) { |
| // if the key is null, we do not need proceed aggregating the record |
| // the record with the table |
| if (key == null) |
| return; |
| |
| // first get the matching windows |
| long timestamp = context().timestamp(); |
| Map<Long, W> matchedWindows = windows.windowsFor(timestamp); |
| |
| long timeFrom = Long.MAX_VALUE; |
| long timeTo = Long.MIN_VALUE; |
| |
| // use range query on window store for efficient reads |
| for (long windowStartMs : matchedWindows.keySet()) { |
| timeFrom = windowStartMs < timeFrom ? windowStartMs : timeFrom; |
| timeTo = windowStartMs > timeTo ? windowStartMs : timeTo; |
| } |
| |
| WindowStoreIterator<T> iter = windowStore.fetch(key, timeFrom, timeTo); |
| |
| // for each matching window, try to update the corresponding key and send to the downstream |
| while (iter.hasNext()) { |
| KeyValue<Long, T> entry = iter.next(); |
| W window = matchedWindows.get(entry.key); |
| |
| if (window != null) { |
| |
| T oldAgg = entry.value; |
| |
| if (oldAgg == null) |
| oldAgg = initializer.apply(); |
| |
| // try to add the new new value (there will never be old value) |
| T newAgg = aggregator.apply(key, value, oldAgg); |
| |
| // update the store with the new value |
| windowStore.put(key, newAgg, window.start()); |
| |
| // forward the aggregated change pair |
| if (sendOldValues) |
| context().forward(new Windowed<>(key, window), new Change<>(newAgg, oldAgg)); |
| else |
| context().forward(new Windowed<>(key, window), new Change<>(newAgg, null)); |
| |
| matchedWindows.remove(entry.key); |
| } |
| } |
| |
| iter.close(); |
| |
| // create the new window for the rest of unmatched window that do not exist yet |
| for (long windowStartMs : matchedWindows.keySet()) { |
| T oldAgg = initializer.apply(); |
| T newAgg = aggregator.apply(key, value, oldAgg); |
| |
| windowStore.put(key, newAgg, windowStartMs); |
| |
| // send the new aggregate pair |
| if (sendOldValues) |
| context().forward(new Windowed<>(key, matchedWindows.get(windowStartMs)), new Change<>(newAgg, oldAgg)); |
| else |
| context().forward(new Windowed<>(key, matchedWindows.get(windowStartMs)), new Change<>(newAgg, null)); |
| } |
| } |
| } |
| |
| @Override |
| public KTableValueGetterSupplier<Windowed<K>, T> view() { |
| |
| return new KTableValueGetterSupplier<Windowed<K>, T>() { |
| |
| public KTableValueGetter<Windowed<K>, T> get() { |
| return new KStreamWindowAggregateValueGetter(); |
| } |
| |
| }; |
| } |
| |
| private class KStreamWindowAggregateValueGetter implements KTableValueGetter<Windowed<K>, T> { |
| |
| private WindowStore<K, T> windowStore; |
| |
| @SuppressWarnings("unchecked") |
| @Override |
| public void init(ProcessorContext context) { |
| windowStore = (WindowStore<K, T>) context.getStateStore(storeName); |
| } |
| |
| @SuppressWarnings("unchecked") |
| @Override |
| public T get(Windowed<K> windowedKey) { |
| K key = windowedKey.value(); |
| W window = (W) windowedKey.window(); |
| |
| // this iterator should contain at most one element |
| Iterator<KeyValue<Long, T>> iter = windowStore.fetch(key, window.start(), window.start()); |
| |
| return iter.hasNext() ? iter.next().value : null; |
| } |
| |
| } |
| } |