mjsax commented on code in PR #21600: URL: https://github.com/apache/kafka/pull/21600#discussion_r2887600699
########## streams/src/main/java/org/apache/kafka/streams/state/internals/SessionToHeadersIteratorAdapter.java: ########## @@ -0,0 +1,64 @@ +/* + * 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.state.internals; + +import org.apache.kafka.common.utils.Bytes; +import org.apache.kafka.streams.KeyValue; +import org.apache.kafka.streams.kstream.Windowed; +import org.apache.kafka.streams.state.KeyValueIterator; + +import static org.apache.kafka.streams.state.internals.SessionToHeadersStoreAdapter.rawAggregationValue; + +/** + * This class is used to ensure backward compatibility at DSL level between + * {@link org.apache.kafka.streams.state.SessionStoreWithHeaders} and + * {@link org.apache.kafka.streams.state.SessionStore}. + * <p> + * When iterating over session entries from a store that stores values with headers, + * this adapter strips the headers prefix so the caller receives raw aggregation bytes + * without headers. + * + * @see SessionToHeadersStoreAdapter + */ +class SessionToHeadersIteratorAdapter implements KeyValueIterator<Windowed<Bytes>, byte[]> { + private final KeyValueIterator<Windowed<Bytes>, byte[]> innerIterator; + + SessionToHeadersIteratorAdapter(final KeyValueIterator<Windowed<Bytes>, byte[]> innerIterator) { + this.innerIterator = innerIterator; + } + + @Override + public void close() { + innerIterator.close(); + } + + @Override + public Windowed<Bytes> peekNextKey() { + return innerIterator.peekNextKey(); + } + + @Override + public boolean hasNext() { + return innerIterator.hasNext(); + } + + @Override + public KeyValue<Windowed<Bytes>, byte[]> next() { + final KeyValue<Windowed<Bytes>, byte[]> keyValue = innerIterator.next(); + return KeyValue.pair(keyValue.key, rawAggregationValue(keyValue.value)); Review Comment: I think the code is correct. Cf. the JavaDocs. `SessionToHeader[...]Adapter` means, that the caller expect a plain session store, but the inner store is actually a header store, so we need to remove headers. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
