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;
022import org.apache.hadoop.hbase.RegionLocations;
023import org.apache.hadoop.hbase.ServerName;
024import org.apache.yetus.audience.InterfaceAudience;
025
026/**
027 * Registry for meta information needed for connection setup to a HBase cluster. Implementations
028 * hold cluster information such as this cluster's id, location of hbase:meta, etc.. Internal use
029 * only.
030 */
031@InterfaceAudience.Private
032public interface ConnectionRegistry extends Closeable {
033
034  /**
035   * Get the location of meta region(s).
036   */
037  CompletableFuture<RegionLocations> getMetaRegionLocations();
038
039  /**
040   * Should only be called once.
041   * <p>
042   * The upper layer should store this value somewhere as it will not be change any more.
043   */
044  CompletableFuture<String> getClusterId();
045
046  /**
047   * Get the address of active HMaster.
048   */
049  CompletableFuture<ServerName> getActiveMaster();
050
051  /**
052   * Return the connection string associated with this registry instance. This value is
053   * informational, used for annotating traces. Values returned may not be valid for establishing a
054   * working cluster connection.
055   */
056  String getConnectionString();
057
058  /**
059   * Closes this instance and releases any system resources associated with it
060   */
061  @Override
062  void close();
063}