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 */
018
019package org.apache.hadoop.hbase.master;
020
021import org.apache.yetus.audience.InterfaceAudience;
022
023/**
024 * Factory to create MetricsMasterSource when given a  MetricsMasterWrapper
025 */
026@InterfaceAudience.Private
027public class MetricsMasterSourceFactoryImpl implements MetricsMasterSourceFactory {
028  private static enum FactoryStorage {
029    INSTANCE;
030    MetricsMasterSource masterSource;
031  }
032
033  @Override
034  public synchronized MetricsMasterSource create(MetricsMasterWrapper masterWrapper) {
035    if (FactoryStorage.INSTANCE.masterSource == null) {
036      FactoryStorage.INSTANCE.masterSource = new MetricsMasterSourceImpl(masterWrapper);
037    }
038    return FactoryStorage.INSTANCE.masterSource;
039  }
040}