content: /*
   * Copyright 1999-2020 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.core.remote;
  
  import com.alibaba.nacos.api.exception.NacosException;
  import com.alibaba.nacos.api.remote.request.Request;
  import com.alibaba.nacos.api.remote.request.RequestMeta;
  import com.alibaba.nacos.api.remote.response.Response;
  import com.alibaba.nacos.core.utils.Loggers;
  import org.springframework.beans.factory.annotation.Autowired;
  
  /**
   * Nacos based request handler.
   *
   * @author liuzunfei
   * @author xiweng.yy
   */
  @SuppressWarnings("PMD.AbstractClassShouldStartWithAbstractNamingRule")
  public abstract class RequestHandler<T extends Request, S extends Response> {
      
      @Autowired
      private RequestFilters requestFilters;
      
      /**
       * Handler request.
       *
       * @param request request
       * @param meta    request meta data
       * @return response
       * @throws NacosException nacos exception when handle request has problem.
       */
      public Response handleRequest(T request, RequestMeta meta) throws NacosException {
          for (AbstractRequestFilter filter : requestFilters.filters) {
              try {
                  Response filterResult = filter.filter(request, meta, this.getClass());
                  if (filterResult != null && !filterResult.isSuccess()) {
                      return filterResult;
                  }
              } catch (Throwable throwable) {
                  Loggers.REMOTE.error("filter error", throwable);
              }
              
          }
          return handle(request, meta);
      }
      
      /**
       * Handler request.
       *
       * @param request request
       * @param meta    request meta data
       * @return response
       * @throws NacosException nacos exception when handle request has problem.
       */
      public abstract S handle(T request, RequestMeta meta) throws NacosException;
      
  }
  