content: /**
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements.  See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You 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.jstorm.daemon.worker;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Map;
  
  /**
   * UpdateListener is used to dynamically update configurations in worker
   * triggered by update topology action
   *
   * @author Jark (wuchong.wc@alibaba-inc.com)
   */
  public class UpdateListener {
      private static final Logger LOG = LoggerFactory.getLogger(UpdateListener.class);
  
      interface IUpdater {
          void update(Map conf);
      }
  
      private List<IUpdater> updaters = new ArrayList<>();
  
      /**
       * register an updater which implement IUpdate
       *
       * @param updater used to update configurations in worker
       */
      public void registerUpdater(IUpdater updater) {
          updaters.add(updater);
      }
  
      /**
       * trigger all updaters' update action
       *
       * @param conf the new worker conf
       */
      public void update(Map conf) {
          for (IUpdater updater : updaters) {
              try {
                  updater.update(conf);
              } catch (Exception e) {
                  LOG.error(e.getMessage(), e);
              }
          }
      }
  
  }
  
  
  