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.processor;
  
  import org.apache.kafka.common.annotation.InterfaceStability.Evolving;
  import org.apache.kafka.common.serialization.Serde;
  import org.apache.kafka.streams.StreamsMetrics;
  import org.apache.kafka.streams.errors.StreamsException;
  import org.apache.kafka.streams.processor.api.RecordMetadata;
  
  import java.io.File;
  import java.util.Map;
  import java.util.Optional;
  
  /**
   * State store context interface.
   */
  public interface StateStoreContext {
  
      /**
       * Returns the application id.
       *
       * @return the application id
       */
      String applicationId();
  
      /**
       * Returns the task id.
       *
       * @return the task id
       */
      TaskId taskId();
  
      /**
       * Return the metadata of the current topic/partition/offset if available.
       * This is defined as the metadata of the record that is currently being
       * processed (or was last processed) by the StreamTask that holds the store.
       * <p>
       * Note that the metadata is not defined during all store interactions, for
       * example, while the StreamTask is running a punctuation.
       *
       * @return metadata of the current record
       */
      Optional<RecordMetadata> recordMetadata();
  
      /**
       * Returns the default key serde.
       *
       * @return the key serializer
       */
      Serde<?> keySerde();
  
      /**
       * Returns the default value serde.
       *
       * @return the value serializer
       */
      Serde<?> valueSerde();
  
      /**
       * Returns the state directory for the partition.
       *
       * @return the state directory
       */
      File stateDir();
  
      /**
       * Returns Metrics instance.
       *
       * @return StreamsMetrics
       */
      StreamsMetrics metrics();
  
      /**
       * Registers and possibly restores the specified storage engine.
       *
       * @param store the storage engine
       * @param stateRestoreCallback the restoration callback logic for log-backed state stores upon restart
       *
       * @throws IllegalStateException If store gets registered after initialized is already finished
       * @throws StreamsException if the store's change log does not contain the partition
       */
      void register(final StateStore store,
                    final StateRestoreCallback stateRestoreCallback);
  
      /**
       * Registers and possibly restores the specified storage engine.
       *
       * @param store the storage engine
       * @param stateRestoreCallback the restoration callback logic for log-backed state stores upon restart
       * @param commitCallback a callback to be invoked upon successful task commit, in case the store
       *                           needs to perform any state tracking when the task is known to be in
       *                           a consistent state. If the store has no such state to track, it may
       *                           use {@link StateStoreContext#register(StateStore, StateRestoreCallback)} instead.
       *                           Persistent stores provided by Kafka Streams use this method to save
       *                           their Position information to local disk, for example.
       *
       * @throws IllegalStateException If store gets registered after initialized is already finished
       * @throws StreamsException if the store's change log does not contain the partition
       */
      @Evolving
      void register(final StateStore store,
                    final StateRestoreCallback stateRestoreCallback,
                    final CommitCallback commitCallback);
  
      /**
       * Returns all the application config properties as key/value pairs.
       *
       * <p> The config properties are defined in the {@link org.apache.kafka.streams.StreamsConfig}
       * object and associated to the StateStoreContext.
       *
       * <p> The type of the values is dependent on the {@link org.apache.kafka.common.config.ConfigDef.Type type} of the property
       * (e.g. the value of {@link org.apache.kafka.streams.StreamsConfig#DEFAULT_KEY_SERDE_CLASS_CONFIG DEFAULT_KEY_SERDE_CLASS_CONFIG}
       * will be of type {@link Class}, even if it was specified as a String to
       * {@link org.apache.kafka.streams.StreamsConfig#StreamsConfig(Map) StreamsConfig(Map)}).
       *
       * @return all the key/values from the StreamsConfig properties
       */
      Map<String, Object> appConfigs();
  
      /**
       * Returns all the application config properties with the given key prefix, as key/value pairs
       * stripping the prefix.
       *
       * <p> The config properties are defined in the {@link org.apache.kafka.streams.StreamsConfig}
       * object and associated to the StateStoreContext.
       *
       * @param prefix the properties prefix
       * @return the key/values matching the given prefix from the StreamsConfig properties.
       */
      Map<String, Object> appConfigsWithPrefix(final String prefix);
  
  }
  