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.task.master.timer;
  
  import java.util.Set;
  
  import backtype.storm.task.TopologyContext;
  import com.alibaba.jstorm.cluster.StormClusterState;
  import com.alibaba.jstorm.task.error.ErrorConstants;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import com.alibaba.jstorm.schedule.Assignment;
  import com.alibaba.jstorm.schedule.default_assign.ResourceWorkerSlot;
  import com.alibaba.jstorm.task.master.TMHandler;
  import com.alibaba.jstorm.task.master.TopologyMasterContext;
  
  public class WorkerSetUpdater implements TMHandler {
      private static final Logger LOG = LoggerFactory.getLogger(WorkerSetUpdater.class);
  
      TopologyMasterContext tmContext;
  
      private StormClusterState zkCluster;
      private TopologyContext context;
  
      @Override
      public void init(TopologyMasterContext tmContext) {
          this.tmContext = tmContext;
          this.zkCluster = tmContext.getZkCluster();
          this.context = tmContext.getContext();
      }
  
  
      @Override
      public void process(Object event) throws Exception {
          try {
              Assignment assignment = tmContext.getZkCluster().assignment_info(tmContext.getTopologyId(), null);
              if (assignment != null) {
                  Set<ResourceWorkerSlot> oldWorkerSet = tmContext.getWorkerSet().get();
                  Set<ResourceWorkerSlot> newWorkerSet = assignment.getWorkers();
                  if (!oldWorkerSet.equals(newWorkerSet)) {
                      LOG.info("Find worker slots has been changed, old:{}, \nnew:{}", oldWorkerSet, newWorkerSet);
                      tmContext.getWorkerSet().set(newWorkerSet);
                      tmContext.getTopologyMetricContext().setWorkerSet(newWorkerSet);
                  }
              }
          } catch (Exception e) {
              String errorInfo = "Failed to get assignment for " + tmContext.getTopologyId();
              LOG.error(errorInfo + e);
              zkCluster.report_task_error(context.getTopologyId(), context.getThisTaskId(),
                      errorInfo, ErrorConstants.WARN, ErrorConstants.CODE_USER);
          }
      }
  
  
      @Override
      public void cleanup() {
      }
  
  }
  