content: /*
   * 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.celeborn.server.common.service.config;
  
  import java.util.ServiceLoader;
  
  import com.google.common.annotations.VisibleForTesting;
  
  import org.apache.celeborn.common.CelebornConf;
  import org.apache.celeborn.common.util.Utils;
  
  public class DynamicConfigServiceFactory {
    private static volatile ConfigService _INSTANCE;
  
    public static ConfigService getConfigService(CelebornConf celebornConf) {
      if (celebornConf.dynamicConfigStoreBackend().isEmpty()) {
        return null;
      }
  
      if (_INSTANCE == null) {
        synchronized (DynamicConfigServiceFactory.class) {
          if (_INSTANCE == null) {
            String configStoreBackend = celebornConf.dynamicConfigStoreBackend().get();
            for (ConfigStore configStore : ServiceLoader.load(ConfigStore.class)) {
              if (configStore.getName().equalsIgnoreCase(configStoreBackend)) {
                configStoreBackend = configStore.getService();
                break;
              }
            }
            _INSTANCE = Utils.instantiateClassWithCelebornConf(configStoreBackend, celebornConf);
          }
        }
      }
  
      return _INSTANCE;
    }
  
    @VisibleForTesting
    public static void reset() {
      if (_INSTANCE != null) {
        _INSTANCE.shutdown();
        _INSTANCE = null;
      }
    }
  }
  