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 org.apache.hadoop.hbase.HRegionLocation; 021import org.apache.hadoop.hbase.TableName; 022import org.apache.yetus.audience.InterfaceAudience; 023 024/** 025 * A Catalog replica selector decides which catalog replica to go for read requests when it is 026 * configured as CatalogReplicaMode.LoadBalance. 027 */ 028@InterfaceAudience.Private 029interface CatalogReplicaLoadBalanceSelector { 030 031 /** 032 * This method is called when input location is stale, i.e, when clients run into 033 * org.apache.hadoop.hbase.NotServingRegionException. 034 * @param loc stale location 035 */ 036 void onError(HRegionLocation loc); 037 038 /** 039 * Select a catalog replica region where client go to loop up the input row key. 040 * 041 * @param tablename table name 042 * @param row key to look up 043 * @param locateType locate type 044 * @return replica id 045 */ 046 int select(TableName tablename, byte[] row, RegionLocateType locateType); 047}