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.master;
019
020import org.apache.hadoop.hbase.ServerName;
021import org.apache.yetus.audience.InterfaceAudience;
022
023/**
024 * Get notification of server registration events. The invocations are inline so make sure your
025 * implementation is fast or else you'll slow hbase.
026 */
027@InterfaceAudience.Private
028public interface ServerListener {
029  /**
030   * Started waiting on RegionServers to check-in.
031   */
032  default void waiting() {
033  }
034
035  /**
036   * The server has joined the cluster.
037   * @param serverName The remote servers name.
038   */
039  default void serverAdded(final ServerName serverName) {
040  }
041
042  /**
043   * The server was removed from the cluster.
044   * @param serverName The remote servers name.
045   */
046  default void serverRemoved(final ServerName serverName) {
047  }
048}