| /** |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with this |
| * work for additional information regarding copyright ownership. The ASF |
| * licenses this file to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT |
| * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the |
| * License for the specific language governing permissions and limitations under |
| * the License. |
| */ |
| package org.apache.bookkeeper.stats; |
| |
| import java.util.concurrent.ConcurrentHashMap; |
| import java.util.concurrent.ConcurrentMap; |
| import org.apache.commons.configuration.Configuration; |
| |
| /** |
| * A {@code CachingStatsProvider} adds the caching functionality to an existing {@code StatsProvider}. |
| * |
| * <p>The stats provider will cache the stats objects created by the other {@code StatsProvider} to allow |
| * the reusability of stats objects and avoid creating a lot of stats objects. |
| */ |
| public class CachingStatsProvider implements StatsProvider { |
| |
| protected final StatsProvider underlying; |
| protected final ConcurrentMap<String, StatsLogger> statsLoggers; |
| |
| public CachingStatsProvider(StatsProvider provider) { |
| this.underlying = provider; |
| this.statsLoggers = new ConcurrentHashMap<String, StatsLogger>(); |
| } |
| |
| @Override |
| public void start(Configuration conf) { |
| this.underlying.start(conf); |
| } |
| |
| @Override |
| public void stop() { |
| this.underlying.stop(); |
| } |
| |
| @Override |
| public StatsLogger getStatsLogger(String scope) { |
| StatsLogger statsLogger = statsLoggers.get(scope); |
| if (null == statsLogger) { |
| StatsLogger newStatsLogger = |
| new CachingStatsLogger(underlying.getStatsLogger(scope)); |
| StatsLogger oldStatsLogger = statsLoggers.putIfAbsent(scope, newStatsLogger); |
| statsLogger = (null == oldStatsLogger) ? newStatsLogger : oldStatsLogger; |
| } |
| return statsLogger; |
| } |
| } |