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.streams.errors.InvalidStateStoreException;
  import org.apache.kafka.streams.processor.StateStore;
  import org.apache.kafka.streams.processor.StateStoreContext;
  import org.apache.kafka.streams.processor.api.ProcessorContext;
  import org.apache.kafka.streams.query.Position;
  import org.apache.kafka.streams.query.PositionBound;
  import org.apache.kafka.streams.query.Query;
  import org.apache.kafka.streams.query.QueryConfig;
  import org.apache.kafka.streams.query.QueryResult;
  import org.apache.kafka.streams.state.TimestampedKeyValueStore;
  import org.apache.kafka.streams.state.ValueAndTimestamp;
  import org.apache.kafka.streams.state.VersionedKeyValueStore;
  import org.apache.kafka.streams.state.VersionedRecord;
  
  /**
   * A wrapper class for non-windowed key-value stores used within the DSL. All such stores are
   * instances of either {@link TimestampedKeyValueStore} or {@link VersionedKeyValueStore}.
   *
   * @param <K> The key type
   * @param <V> The value type
   */
  public class KeyValueStoreWrapper<K, V> implements StateStore {
  
      public static final long PUT_RETURN_CODE_IS_LATEST
          = VersionedKeyValueStore.PUT_RETURN_CODE_VALID_TO_UNDEFINED;
  
      private TimestampedKeyValueStore<K, V> timestampedStore = null;
      private VersionedKeyValueStore<K, V> versionedStore = null;
  
      // same as either timestampedStore or versionedStore above. kept merely as a convenience
      // to simplify implementation for methods which do not depend on store type.
      private StateStore store;
  
      public KeyValueStoreWrapper(final ProcessorContext<?, ?> context, final String storeName) {
          try {
              // first try timestamped store
              timestampedStore = context.getStateStore(storeName);
              store = timestampedStore;
              return;
          } catch (final ClassCastException e) {
              // ignore since could be versioned store instead
          }
  
          try {
              // next try versioned store
              versionedStore = context.getStateStore(storeName);
              store = versionedStore;
          } catch (final ClassCastException e) {
              store = context.getStateStore(storeName);
              final String storeType = store == null ? "null" : store.getClass().getName();
              throw new InvalidStateStoreException("KTable source state store must implement either "
                  + "TimestampedKeyValueStore or VersionedKeyValueStore. Got: " + storeType);
          }
      }
  
      public ValueAndTimestamp<V> get(final K key) {
          if (timestampedStore != null) {
              return timestampedStore.get(key);
          }
          if (versionedStore != null) {
              final VersionedRecord<V> versionedRecord = versionedStore.get(key);
              return versionedRecord == null
                  ? null
                  : ValueAndTimestamp.make(versionedRecord.value(), versionedRecord.timestamp());
          }
          throw new IllegalStateException("KeyValueStoreWrapper must be initialized with either timestamped or versioned store");
      }
  
      public ValueAndTimestamp<V> get(final K key, final long asOfTimestamp) {
          if (!isVersionedStore()) {
              throw new UnsupportedOperationException("get(key, timestamp) is only supported for versioned stores");
          }
          final VersionedRecord<V> versionedRecord = versionedStore.get(key, asOfTimestamp);
          return versionedRecord == null ? null : ValueAndTimestamp.make(versionedRecord.value(), versionedRecord.timestamp());
      }
  
      /**
       * @return {@code -1} if the put record is the latest for its key, and {@code Long.MIN_VALUE}
       *         if the put was rejected (i.e., due to grace period having elapsed for a versioned
       *         store). If neither, any other long value may be returned.
       */
      public long put(final K key, final V value, final long timestamp) {
          if (timestampedStore != null) {
              timestampedStore.put(key, ValueAndTimestamp.make(value, timestamp));
              return PUT_RETURN_CODE_IS_LATEST;
          }
          if (versionedStore != null) {
              return versionedStore.put(key, value, timestamp);
          }
          throw new IllegalStateException("KeyValueStoreWrapper must be initialized with either timestamped or versioned store");
      }
  
      public StateStore store() {
          return store;
      }
  
      public boolean isVersionedStore() {
          return versionedStore != null;
      }
  
      @Override
      public String name() {
          return store.name();
      }
  
      @Override
      public void init(final StateStoreContext stateStoreContext, final StateStore root) {
          store.init(stateStoreContext, root);
      }
  
      @Override
      public void flush() {
          store.flush();
      }
  
      @Override
      public void close() {
          store.close();
      }
  
      @Override
      public boolean persistent() {
          return store.persistent();
      }
  
      @Override
      public boolean isOpen() {
          return store.isOpen();
      }
  
      @Override
      public <R> QueryResult<R> query(final Query<R> query, final PositionBound positionBound, final QueryConfig config) {
          return store.query(query, positionBound, config);
      }
  
      @Override
      public Position getPosition() {
          return store.getPosition();
      }
  }
  