content: /*
   * Copyright 1999-$toady.year Alibaba Group Holding Ltd.
   *
   * Licensed 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.alibaba.nacos.config.server.service.query;
  
  import com.alibaba.nacos.common.spi.NacosServiceLoader;
  import com.alibaba.nacos.config.server.exception.NacosConfigException;
  import com.alibaba.nacos.sys.env.EnvUtil;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import java.util.Optional;
  
  /**
   * Service class for initializing and retrieving the configuration query request extractor.
   *
   * @author Nacos
   */
  public class ConfigChainRequestExtractorService {
      
      private static final Logger LOGGER = LoggerFactory.getLogger(ConfigChainRequestExtractorService.class);
      
      private static ConfigQueryChainRequestExtractor extractor;
      
      static {
          String curExtractor = EnvUtil.getProperty("nacos.config.query.chain.request.extractor", "nacos");
          Optional<ConfigQueryChainRequestExtractor> optionalBuilder = NacosServiceLoader.load(ConfigQueryChainRequestExtractor.class)
                  .stream()
                  .filter(builder -> builder.getName().equals(curExtractor))
                  .findFirst();
          if (optionalBuilder.isPresent()) {
              extractor = optionalBuilder.get();
              LOGGER.info("ConfigQueryRequestExtractor has been initialized successfully with extractor: {}", curExtractor);
          } else {
              String errorMessage = "No suitable ConfigQueryRequestExtractor found for name: " + curExtractor;
              LOGGER.error(errorMessage);
              throw new NacosConfigException(errorMessage);
          }
      }
      
      public static ConfigQueryChainRequestExtractor getExtractor() {
          return extractor;
      }
  }