code: /*
   * 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.skywalking.oap.server.cluster.plugin.standalone;
  
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.List;
  import org.apache.skywalking.oap.server.core.cluster.ClusterCoordinator;
  import org.apache.skywalking.oap.server.core.cluster.RemoteInstance;
  
  /**
   * A cluster manager simulator. Work in memory only. Also return the current instance.
   */
  public class StandaloneManager extends ClusterCoordinator {
  
      private volatile RemoteInstance remoteInstance;
  
      @Override
      public void registerRemote(RemoteInstance remoteInstance) {
          this.remoteInstance = remoteInstance;
          this.remoteInstance.getAddress().setSelf(true);
      }
  
      @Override
      public List<RemoteInstance> queryRemoteNodes() {
          if (remoteInstance == null) {
              return new ArrayList(0);
          }
          ArrayList remoteList = new ArrayList(1);
          remoteList.add(remoteInstance);
          return remoteList;
      }
  
      public void notifyWatchers() {
          notifyWatchers(Collections.singletonList(remoteInstance));
      }
  
      @Override
      public void start() {
      }
  }
  