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.slots.statistic;
  
  import java.util.Collection;
  import java.util.Map;
  import java.util.concurrent.ConcurrentHashMap;
  
  import com.alibaba.csp.sentinel.node.DefaultNode;
  import com.alibaba.csp.sentinel.slotchain.ProcessorSlotEntryCallback;
  import com.alibaba.csp.sentinel.slotchain.ProcessorSlotExitCallback;
  
  /**
   * <p>
   * Callback registry for {@link StatisticSlot}. Now two kind of callbacks are supported:
   * <ul>
   * <li>{@link ProcessorSlotEntryCallback}: callback for entry (passed and blocked)</li>
   * <li>{@link ProcessorSlotExitCallback}: callback for exiting {@link StatisticSlot}</li>
   * </ul>
   * </p>
   *
   * @author Eric Zhao
   * @since 0.2.0
   */
  public final class StatisticSlotCallbackRegistry {
  
      private static final Map<String, ProcessorSlotEntryCallback<DefaultNode>> entryCallbackMap
          = new ConcurrentHashMap<String, ProcessorSlotEntryCallback<DefaultNode>>();
  
      private static final Map<String, ProcessorSlotExitCallback> exitCallbackMap
          = new ConcurrentHashMap<String, ProcessorSlotExitCallback>();
  
      public static void clearEntryCallback() {
          entryCallbackMap.clear();
      }
  
      public static void clearExitCallback() {
          exitCallbackMap.clear();
      }
  
      public static void addEntryCallback(String key, ProcessorSlotEntryCallback<DefaultNode> callback) {
          entryCallbackMap.put(key, callback);
      }
  
      public static void addExitCallback(String key, ProcessorSlotExitCallback callback) {
          exitCallbackMap.put(key, callback);
      }
  
      public static ProcessorSlotEntryCallback<DefaultNode> removeEntryCallback(String key) {
          if (key == null) {
              return null;
          }
          return entryCallbackMap.remove(key);
      }
  
      public static ProcessorSlotExitCallback removeExitCallback(String key) {
          if (key == null) {
              return null;
          }
          return exitCallbackMap.remove(key);
      }
  
      public static Collection<ProcessorSlotEntryCallback<DefaultNode>> getEntryCallbacks() {
          return entryCallbackMap.values();
      }
  
      public static Collection<ProcessorSlotExitCallback> getExitCallbacks() {
          return exitCallbackMap.values();
      }
  
      private StatisticSlotCallbackRegistry() {}
  }
  