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