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.gms;
  
  import java.util.Map;
  import javax.annotation.Nullable;
  
  import org.apache.cassandra.locator.InetAddressAndPort;
  import org.apache.cassandra.utils.CassandraVersion;
  
  public interface IGossiper
  {
      void register(IEndpointStateChangeSubscriber subscriber);
      void unregister(IEndpointStateChangeSubscriber subscriber);
  
      @Nullable
      EndpointState getEndpointStateForEndpoint(InetAddressAndPort ep);
      void notifyFailureDetector(Map<InetAddressAndPort, EndpointState> remoteEpStateMap);
      void applyStateLocally(Map<InetAddressAndPort, EndpointState> epStateMap);
      @Nullable
      default CassandraVersion getReleaseVersion(InetAddressAndPort ep)
      {
          EndpointState state = getEndpointStateForEndpoint(ep);
          return state != null ? state.getReleaseVersion() : null;
      }
  }
  