001/**
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018package org.apache.hadoop.hbase.client;
019
020import java.io.Closeable;
021import java.util.concurrent.CompletableFuture;
022
023import org.apache.hadoop.hbase.RegionLocations;
024import org.apache.hadoop.hbase.ServerName;
025import org.apache.yetus.audience.InterfaceAudience;
026
027/**
028 * Implementations hold cluster information such as this cluster's id, location of hbase:meta, etc..
029 * All stuffs that may be related to zookeeper at client side are placed here.
030 * <p>
031 * Internal use only.
032 */
033@InterfaceAudience.Private
034interface AsyncRegistry extends Closeable {
035
036  /**
037   * Get the location of meta region.
038   */
039  CompletableFuture<RegionLocations> getMetaRegionLocation();
040
041  /**
042   * Should only be called once.
043   * <p>
044   * The upper layer should store this value somewhere as it will not be change any more.
045   */
046  CompletableFuture<String> getClusterId();
047
048  /**
049   * Get the number of 'running' regionservers.
050   */
051  CompletableFuture<Integer> getCurrentNrHRS();
052
053  /**
054   * Get the address of HMaster.
055   */
056  CompletableFuture<ServerName> getMasterAddress();
057
058  /**
059   * Get the info port of HMaster.
060   */
061  CompletableFuture<Integer> getMasterInfoPort();
062
063  /**
064   * Closes this instance and releases any system resources associated with it
065   */
066  @Override
067  void close();
068}