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 storm.trident.spout;
  
  import backtype.storm.Config;
  import backtype.storm.task.TopologyContext;
  import backtype.storm.topology.BasicOutputCollector;
  import backtype.storm.topology.IBasicBolt;
  import backtype.storm.topology.OutputFieldsDeclarer;
  import storm.trident.topology.TransactionAttempt;
  import backtype.storm.tuple.Fields;
  import backtype.storm.tuple.Tuple;
  import backtype.storm.tuple.Values;
  import java.util.Map;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  import storm.trident.topology.MasterBatchCoordinator;
  import storm.trident.topology.state.RotatingTransactionalState;
  import storm.trident.topology.state.TransactionalState;
  
  public class TridentSpoutCoordinator implements IBasicBolt {
      public static final Logger LOG = LoggerFactory.getLogger(TridentSpoutCoordinator.class);
      private static final String META_DIR = "meta";
  
      ITridentSpout<Object> _spout;
      ITridentSpout.BatchCoordinator<Object> _coord;
      RotatingTransactionalState _state;
      TransactionalState _underlyingState;
      String _id;
  
      public TridentSpoutCoordinator(String id, ITridentSpout<Object> spout) {
          _spout = spout;
          _id = id;
      }
  
      @Override
      public void prepare(Map conf, TopologyContext context) {
          _coord = _spout.getCoordinator(_id, conf, context);
          _underlyingState = TransactionalState.newCoordinatorState(conf, _id);
          _state = new RotatingTransactionalState(_underlyingState, META_DIR);
      }
  
      @Override
      public void execute(Tuple tuple, BasicOutputCollector collector) {
          TransactionAttempt attempt = (TransactionAttempt) tuple.getValue(0);
  
          if (tuple.getSourceStreamId().equals(MasterBatchCoordinator.SUCCESS_STREAM_ID)) {
              _state.cleanupBefore(attempt.getTransactionId());
              _coord.success(attempt.getTransactionId());
          } else {
              long txid = attempt.getTransactionId();
              Object prevMeta = _state.getPreviousState(txid);
              Object meta = _coord.initializeTransaction(txid, prevMeta, _state.getState(txid));
              _state.overrideState(txid, meta);
              collector.emit(MasterBatchCoordinator.BATCH_STREAM_ID, new Values(attempt, meta));
          }
  
      }
  
      @Override
      public void cleanup() {
          _coord.close();
          _underlyingState.close();
      }
  
      @Override
      public void declareOutputFields(OutputFieldsDeclarer declarer) {
          declarer.declareStream(MasterBatchCoordinator.BATCH_STREAM_ID, new Fields("tx", "metadata"));
      }
  
      @Override
      public Map<String, Object> getComponentConfiguration() {
          Config ret = new Config();
          ret.setMaxTaskParallelism(1);
          return ret;
      }
  }
  