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.transactional.state.task;
  
  import static org.slf4j.LoggerFactory.getLogger;
  
  import java.util.Collection;
  import java.util.HashMap;
  import java.util.Map;
  import java.util.Set;
  
  import org.slf4j.Logger;
  
  import com.alibaba.jstorm.client.ConfigExtension;
  import com.alibaba.jstorm.transactional.state.KeyRangeState;
  import com.alibaba.jstorm.transactional.state.TransactionState;
  import com.alibaba.jstorm.utils.JStormUtils;
  
  public class KeyRangeStateTaskInit implements ITaskStateInitOperator {
      private static final Logger LOG = getLogger(KeyRangeStateTaskInit.class);
  
      @Override
      public Object getTaskInitState(Map conf, int currTaskId, Set<Integer> currComponentTasks, Map<Integer, TransactionState> prevComponentTaskStates) {
          Map<Integer, String> currKeyRangeToCheckpoints = new HashMap<Integer, String>();
          Map<Integer, String> prevKeyRangeToCheckpoints = getAllKeyRangeCheckpointPaths(prevComponentTaskStates.values());
          int componentTaskNum = currComponentTasks.size();
          int taskIndex = JStormUtils.getTaskIndex(currTaskId, currComponentTasks);
          int prevKeyRangeNum = prevKeyRangeToCheckpoints.size();
          int configKeyRangeNum = ConfigExtension.getKeyRangeNum(conf);
          int currKeyRangeNum = JStormUtils.getScaleOutNum(configKeyRangeNum, componentTaskNum);
          Collection<Integer> currKeyRanges = KeyRangeState.keyRangesByTaskIndex(currKeyRangeNum, componentTaskNum, taskIndex);
          LOG.debug("currKeyRanges: {}, prevKeyRangeToCheckpoints : {}", currKeyRanges, prevKeyRangeToCheckpoints);
  
          // Check if scale-out of key range happens
          if (currKeyRangeNum > prevKeyRangeNum) {
              // key range number increases by 2^n times by default
              for (Integer keyRange : currKeyRanges) {
                  currKeyRangeToCheckpoints.put(keyRange, prevKeyRangeToCheckpoints.get(keyRange % prevKeyRangeNum));
              }
          } else {
              for (Integer keyRange : currKeyRanges) {
                  currKeyRangeToCheckpoints.put(keyRange, prevKeyRangeToCheckpoints.get(keyRange));
              }
          }
          return currKeyRangeToCheckpoints;
      }
  
      private Map<Integer, String> getAllKeyRangeCheckpointPaths(Collection<TransactionState> allStates) {
          Map<Integer, String> keyRangeToCheckpoints = new HashMap<Integer, String>();
          for (TransactionState state : allStates) {
              Map<Integer, String> checkpoint = (Map<Integer, String>) state.getUserCheckpoint();
              if (checkpoint != null)
                  keyRangeToCheckpoints.putAll(checkpoint);
          }
          return keyRangeToCheckpoints;
          
      }
  }