content: /**
   * Copyright 2020 Alibaba Group Holding Limited.
   *
   * <p>Licensed 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
   *
   * <p>http://www.apache.org/licenses/LICENSE-2.0
   *
   * <p>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 com.alibaba.graphscope.groot.discovery;
  
  import com.alibaba.graphscope.groot.common.RoleType;
  
  import java.util.Map;
  
  public interface NodeDiscovery {
  
      void start();
  
      void stop();
  
      void addListener(Listener listener);
  
      void removeListener(Listener listener);
  
      GrootNode getLocalNode();
  
      interface Listener {
          void nodesJoin(RoleType role, Map<Integer, GrootNode> nodes);
  
          void nodesLeft(RoleType role, Map<Integer, GrootNode> nodes);
      }
  }
  