| /** |
| * 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 com.twitter.distributedlog.feature; |
| |
| import com.twitter.distributedlog.config.ConcurrentBaseConfiguration; |
| import org.apache.bookkeeper.feature.CacheableFeatureProvider; |
| import org.apache.bookkeeper.feature.Feature; |
| import org.apache.bookkeeper.feature.FeatureProvider; |
| import org.apache.bookkeeper.feature.SettableFeature; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import java.util.concurrent.ConcurrentMap; |
| |
| /** |
| * Feature Provider that load features from configuration |
| */ |
| class ConfigurationFeatureProvider extends CacheableFeatureProvider { |
| |
| private static final Logger logger = LoggerFactory.getLogger(ConfigurationFeatureProvider.class); |
| |
| static SettableFeature makeFeature(ConcurrentBaseConfiguration featuresConf, |
| ConcurrentMap<String, SettableFeature> features, |
| String featureName) { |
| SettableFeature feature = features.get(featureName); |
| if (null == feature) { |
| int availability = featuresConf.getInt(featureName, 0); |
| feature = new SettableFeature(featureName, availability); |
| SettableFeature oldFeature = |
| features.putIfAbsent(featureName, feature); |
| if (null != oldFeature) { |
| feature = oldFeature; |
| } else { |
| logger.info("Load feature {}={}", featureName, availability); |
| } |
| } |
| return feature; |
| } |
| |
| private final ConcurrentBaseConfiguration featuresConf; |
| private final ConcurrentMap<String, SettableFeature> features; |
| |
| ConfigurationFeatureProvider(String rootScope, |
| ConcurrentBaseConfiguration featuresConf, |
| ConcurrentMap<String, SettableFeature> features) { |
| super(rootScope); |
| this.featuresConf = featuresConf; |
| this.features = features; |
| } |
| |
| @Override |
| protected Feature makeFeature(String featureName) { |
| return makeFeature(featuresConf, features, featureName); |
| } |
| |
| @Override |
| protected FeatureProvider makeProvider(String fullScopeName) { |
| return new ConfigurationFeatureProvider( |
| fullScopeName, featuresConf, features); |
| } |
| } |