content: /*
   * The Alluxio Open Foundation licenses this work under the Apache License, version 2.0
   * (the "License"). You may not use this work except in compliance with the License, which is
   * available at www.apache.org/licenses/LICENSE-2.0
   *
   * This software is distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
   * either express or implied, as more fully set forth in the License.
   *
   * See the NOTICE file distributed with this work for information regarding copyright ownership.
   */
  
  package alluxio.master;
  
  import alluxio.Server;
  import alluxio.exception.status.UnavailableException;
  import alluxio.grpc.GrpcService;
  import alluxio.grpc.ServiceType;
  import alluxio.master.journal.JournalContext;
  import alluxio.master.journal.Journaled;
  
  import java.util.Collections;
  import java.util.Map;
  
  /**
   * This interface contains common operations for all masters.
   */
  public interface Master extends Journaled, Server<Boolean> {
    /**
     * @return a journal context for writing journal entries to the master
     */
    JournalContext createJournalContext() throws UnavailableException;
  
    /**
     * @return a master context
     */
    MasterContext getMasterContext();
  
    /**
     * @return a map from service names to gRPC services that serve RPCs for this master,
     * if the master is a standby master.
     */
    default Map<ServiceType, GrpcService> getStandbyServices() {
      return Collections.emptyMap();
    }
  }
  