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 org.springframework.beans.factory.annotation.Autowired;
  
  import javax.annotation.PostConstruct;
  import java.lang.reflect.Method;
  import java.lang.reflect.ParameterizedType;
  import java.lang.reflect.Type;
  
  /**
   * interceptor fo request.
   *
   * @author liuzunfei
   * @version $Id: AbstractRequestFilter.java, v 0.1 2020年09月14日 11:46 AM liuzunfei Exp $
   */
  public abstract class AbstractRequestFilter {
      
      @Autowired
      private RequestFilters requestFilters;
      
      public AbstractRequestFilter() {
      }
      
      @PostConstruct
      public void init() {
          requestFilters.registerFilter(this);
      }
      
      protected Method getHandleMethod(Class handlerClazz) throws NacosException {
          try {
              Method method = handlerClazz.getMethod("handle", Request.class, RequestMeta.class);
              return method;
          } catch (NoSuchMethodException e) {
              throw new NacosException(NacosException.SERVER_ERROR, e);
          }
      }
      
      protected <T> Response getDefaultResponseInstance(Class handlerClazz) throws NacosException {
          ParameterizedType parameterizedType = (ParameterizedType) handlerClazz.getGenericSuperclass();
          try {
              Type[] actualTypeArguments = parameterizedType.getActualTypeArguments();
              return (Response) Class.forName(actualTypeArguments[1].getTypeName()).newInstance();
              
          } catch (Exception e) {
              throw new NacosException(NacosException.SERVER_ERROR, e);
          }
      }
      
      /**
       * filter request.
       *
       * @param request      request.
       * @param meta         request meta.
       * @param handlerClazz request handler clazz.
       * @return response
       * @throws NacosException NacosException.
       */
      protected abstract Response filter(Request request, RequestMeta meta, Class handlerClazz) throws NacosException;
  }
  