1 /** 2 * Licensed to the Apache Software Foundation (ASF) under one 3 * or more contributor license agreements. See the NOTICE file 4 * distributed with this work for additional information 5 * regarding copyright ownership. The ASF licenses this file 6 * to you under the Apache License, Version 2.0 (the 7 * "License"); you may not use this file except in compliance 8 * with the License. You may obtain a copy of the License at 9 * 10 * http://www.apache.org/licenses/LICENSE-2.0 11 * 12 * Unless required by applicable law or agreed to in writing, software 13 * distributed under the License is distributed on an "AS IS" BASIS, 14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 15 * See the License for the specific language governing permissions and 16 * limitations under the License. 17 */ 18 19 package org.apache.hadoop.hbase.master; 20 21 import org.apache.hadoop.hbase.classification.InterfaceAudience; 22 23 /** 24 * Factory to create MetricsMasterSource when given a MetricsMasterWrapper 25 */ 26 @InterfaceAudience.Private 27 public class MetricsMasterSourceFactoryImpl implements MetricsMasterSourceFactory { 28 private static enum FactoryStorage { 29 INSTANCE; 30 MetricsMasterSource masterSource; 31 } 32 33 @Override 34 public synchronized MetricsMasterSource create(MetricsMasterWrapper masterWrapper) { 35 if (FactoryStorage.INSTANCE.masterSource == null) { 36 FactoryStorage.INSTANCE.masterSource = new MetricsMasterSourceImpl(masterWrapper); 37 } 38 return FactoryStorage.INSTANCE.masterSource; 39 } 40 }