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.connect.storage;
  
  import org.apache.kafka.connect.runtime.WorkerConfig;
  import org.apache.kafka.connect.util.Callback;
  
  import java.nio.ByteBuffer;
  import java.util.Collection;
  import java.util.Map;
  import java.util.Set;
  import java.util.concurrent.Future;
  
  /**
   * <p>
   * OffsetBackingStore is an interface for storage backends that store key-value data. The backing
   * store doesn't need to handle serialization or deserialization. It only needs to support
   * reading/writing bytes. Since it is expected these operations will require network
   * operations, only bulk operations are supported.
   * </p>
   * <p>
   * Since OffsetBackingStore is a shared resource that may be used by many OffsetStorage instances
   * that are associated with individual tasks, the caller must be sure keys include information about the
   * connector so that the shared namespace does not result in conflicting keys.
   * </p>
   */
  public interface OffsetBackingStore {
  
      /**
       * Start this offset store.
       */
      void start();
  
      /**
       * Stop the backing store. Implementations should attempt to shutdown gracefully, but not block
       * indefinitely.
       */
      void stop();
  
      /**
       * Get the values for the specified keys
       * @param keys list of keys to look up
       * @return future for the resulting map from key to value
       */
      Future<Map<ByteBuffer, ByteBuffer>> get(Collection<ByteBuffer> keys);
  
      /**
       * Set the specified keys and values.
       * @param values map from key to value
       * @param callback callback to invoke on completion
       * @return void future for the operation
       */
      Future<Void> set(Map<ByteBuffer, ByteBuffer> values, Callback<Void> callback);
  
      /**
       * Get all the partitions for the specified connector.
       * @param connectorName the name of the connector whose partitions are to be retrieved
       * @return set of connector partitions
       */
      Set<Map<String, Object>> connectorPartitions(String connectorName);
  
      /**
       * Configure class with the given key-value pairs
       * @param config can be DistributedConfig or StandaloneConfig
       */
      void configure(WorkerConfig config);
  }
  