content: /*
   * 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.kstream.Windowed;
  import org.apache.kafka.streams.processor.StateStore;
  import org.apache.kafka.streams.processor.StateStoreContext;
  import org.apache.kafka.streams.processor.internals.InternalProcessorContext;
  import org.apache.kafka.streams.state.KeyValueIterator;
  import org.apache.kafka.streams.state.WindowStore;
  import org.apache.kafka.streams.state.WindowStoreIterator;
  
  import static java.util.Objects.requireNonNull;
  import static org.apache.kafka.streams.processor.internals.ProcessorContextUtils.asInternalProcessorContext;
  
  /**
   * Simple wrapper around a {@link WindowStore} to support writing
   * updates to a changelog
   */
  class ChangeLoggingWindowBytesStore
          extends WrappedStateStore<WindowStore<Bytes, byte[]>, byte[], byte[]>
          implements WindowStore<Bytes, byte[]> {
  
      interface ChangeLoggingKeySerializer {
          Bytes serialize(final Bytes key, final long timestamp, final int seqnum);
      }
  
      private final boolean retainDuplicates;
      InternalProcessorContext<?, ?> internalContext;
      private int seqnum = 0;
      private final ChangeLoggingKeySerializer keySerializer;
  
      ChangeLoggingWindowBytesStore(final WindowStore<Bytes, byte[]> bytesStore,
                                    final boolean retainDuplicates,
                                    final ChangeLoggingKeySerializer keySerializer) {
          super(bytesStore);
          this.retainDuplicates = retainDuplicates;
          this.keySerializer = requireNonNull(keySerializer, "keySerializer");
      }
  
      @Override
      public void init(final StateStoreContext stateStoreContext,
                       final StateStore root) {
          internalContext = asInternalProcessorContext(stateStoreContext);
          super.init(stateStoreContext, root);
      }
  
      @Override
      public byte[] fetch(final Bytes key,
                          final long timestamp) {
          return wrapped().fetch(key, timestamp);
      }
  
      @Override
      public WindowStoreIterator<byte[]> fetch(final Bytes key,
                                               final long from,
                                               final long to) {
          return wrapped().fetch(key, from, to);
      }
  
      @Override
      public WindowStoreIterator<byte[]> backwardFetch(final Bytes key,
                                                       final long timeFrom,
                                                       final long timeTo) {
          return wrapped().backwardFetch(key, timeFrom, timeTo);
      }
  
      @Override
      public KeyValueIterator<Windowed<Bytes>, byte[]> fetch(final Bytes keyFrom,
                                                             final Bytes keyTo,
                                                             final long timeFrom,
                                                             final long to) {
          return wrapped().fetch(keyFrom, keyTo, timeFrom, to);
      }
  
      @Override
      public KeyValueIterator<Windowed<Bytes>, byte[]> backwardFetch(final Bytes keyFrom,
                                                                     final Bytes keyTo,
                                                                     final long timeFrom,
                                                                     final long timeTo) {
          return wrapped().backwardFetch(keyFrom, keyTo, timeFrom, timeTo);
      }
  
      @Override
      public KeyValueIterator<Windowed<Bytes>, byte[]> all() {
          return wrapped().all();
      }
  
  
      @Override
      public KeyValueIterator<Windowed<Bytes>, byte[]> backwardAll() {
          return wrapped().backwardAll();
      }
  
      @Override
      public KeyValueIterator<Windowed<Bytes>, byte[]> fetchAll(final long timeFrom,
                                                                final long timeTo) {
          return wrapped().fetchAll(timeFrom, timeTo);
      }
  
      @Override
      public KeyValueIterator<Windowed<Bytes>, byte[]> backwardFetchAll(final long timeFrom,
                                                                        final long timeTo) {
          return wrapped().backwardFetchAll(timeFrom, timeTo);
      }
  
      @Override
      public void put(final Bytes key,
                      final byte[] value,
                      final long windowStartTimestamp) {
          wrapped().put(key, value, windowStartTimestamp);
  
          log(keySerializer.serialize(key, windowStartTimestamp, maybeUpdateSeqnumForDups()), value);
      }
  
      void log(final Bytes key, final byte[] value) {
          internalContext.logChange(name(), key, value, internalContext.recordContext().timestamp(), wrapped().getPosition());
      }
  
      private int maybeUpdateSeqnumForDups() {
          if (retainDuplicates) {
              seqnum = (seqnum + 1) & 0x7FFFFFFF;
          }
          return seqnum;
      }
  }
  