content: /*
   * Copyright 1999-2018 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.csp.sentinel.cluster.server.processor;
  
  import java.util.List;
  import java.util.Map;
  import java.util.concurrent.ConcurrentHashMap;
  
  import com.alibaba.csp.sentinel.cluster.annotation.RequestType;
  import com.alibaba.csp.sentinel.spi.SpiLoader;
  import com.alibaba.csp.sentinel.util.AssertUtil;
  
  /**
   * @author Eric Zhao
   * @since 1.4.0
   */
  public final class RequestProcessorProvider {
  
      private static final Map<Integer, RequestProcessor> PROCESSOR_MAP = new ConcurrentHashMap<>();
  
      static {
          loadAndInit();
      }
  
      private static void loadAndInit() {
          List<RequestProcessor> processors = SpiLoader.of(RequestProcessor.class).loadInstanceList();
          for (RequestProcessor processor : processors) {
              Integer type = parseRequestType(processor);
              if (type != null) {
                  PROCESSOR_MAP.put(type, processor);
              }
          }
      }
  
      private static Integer parseRequestType(RequestProcessor processor) {
          RequestType requestType = processor.getClass().getAnnotation(RequestType.class);
          if (requestType != null) {
              return requestType.value();
          } else {
              return null;
          }
      }
  
      public static RequestProcessor getProcessor(int type) {
          return PROCESSOR_MAP.get(type);
      }
  
      static void addProcessorIfAbsent(int type, RequestProcessor processor) {
          PROCESSOR_MAP.putIfAbsent(type, processor);
      }
  
      static void addProcessor(int type, RequestProcessor processor) {
          AssertUtil.notNull(processor, "processor cannot be null");
          PROCESSOR_MAP.put(type, processor);
      }
  
      private RequestProcessorProvider() {}
  }
  