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.cassandra.sidecar.restore;
  
  import org.apache.cassandra.sidecar.common.response.TokenRangeReplicasResponse;
  import org.jetbrains.annotations.NotNull;
  import org.jetbrains.annotations.Nullable;
  
  /**
   * To receive notifications on ring topology changed
   */
  public interface RingTopologyChangeListener
  {
      /**
       * Notification on ring topology changed
       * @param keyspace keyspace (which defines replication factor) to derive the topology from
       * @param oldTopology old topology. The value is nullable. When the ring topology of the keyspace is just learned, the value is null.
       * @param newTopology new topology. The value is always non-null
       */
      void onRingTopologyChanged(String keyspace,
                                 @Nullable TokenRangeReplicasResponse oldTopology,
                                 @NotNull TokenRangeReplicasResponse newTopology);
  }
  