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.handler;
  
  import com.alibaba.nacos.config.server.service.query.model.ConfigQueryChainRequest;
  import com.alibaba.nacos.config.server.service.query.model.ConfigQueryChainResponse;
  
  import java.io.IOException;
  
  /**
   * Configuration Query Handler Interface.
   * This interface defines the standard methods for handling configuration query requests.
   *
   * @author Nacos
   */
  public interface ConfigQueryHandler {
      
      /**
       * Gets the name of the handler.
       * @return The name of the handler.
       */
      String getName();
      
      /**
       * Handles the configuration query request.
       * If the current handler cannot process the request, it should throw an IOException.
       * @param request The configuration query request.
       * @return The response to the configuration query.
       * @throws IOException If an I/O error occurs.
       */
      ConfigQueryChainResponse handle(ConfigQueryChainRequest request) throws IOException;
      
      /**
       * Sets the next handler in the chain.
       * @param nextHandler The next handler to which the request can be passed if the current handler cannot process it.
       */
      void setNextHandler(ConfigQueryHandler nextHandler);
      
      /**
       * Gets the next handler in the chain.
       * @return The next handler.
       */
      ConfigQueryHandler getNextHandler();
  }
  