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.planner.processor;
  
  import backtype.storm.task.TopologyContext;
  import storm.trident.topology.TransactionAttempt;
  import backtype.storm.tuple.Fields;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Map;
  import storm.trident.operation.TridentOperationContext;
  import storm.trident.planner.ProcessorContext;
  import storm.trident.planner.TridentProcessor;
  import storm.trident.state.State;
  import storm.trident.state.StateUpdater;
  import storm.trident.tuple.TridentTuple;
  import storm.trident.tuple.TridentTuple.Factory;
  import storm.trident.tuple.TridentTupleView.ProjectionFactory;
  
  public class PartitionPersistProcessor implements TridentProcessor {
      StateUpdater _updater;
      State _state;
      String _stateId;
      TridentContext _context;
      Fields _inputFields;
      ProjectionFactory _projection;
      FreshCollector _collector;
  
      public PartitionPersistProcessor(String stateId, Fields inputFields, StateUpdater updater) {
          _updater = updater;
          _stateId = stateId;
          _inputFields = inputFields;
      }
  
      @Override
      public void prepare(Map conf, TopologyContext context, TridentContext tridentContext) {
          List<Factory> parents = tridentContext.getParentTupleFactories();
          if (parents.size() != 1) {
              throw new RuntimeException("Partition persist operation can only have one parent");
          }
          _context = tridentContext;
          _state = (State) context.getTaskData(_stateId);
          _projection = new ProjectionFactory(parents.get(0), _inputFields);
          _collector = new FreshCollector(tridentContext);
          _updater.prepare(conf, new TridentOperationContext(context, _projection));
      }
  
      @Override
      public void cleanup() {
          _updater.cleanup();
      }
  
      @Override
      public void startBatch(ProcessorContext processorContext) {
          processorContext.state[_context.getStateIndex()] = new ArrayList<TridentTuple>();
      }
  
      @Override
      public void execute(ProcessorContext processorContext, String streamId, TridentTuple tuple) {
          ((List) processorContext.state[_context.getStateIndex()]).add(_projection.create(tuple));
      }
  
      @Override
      public void finishBatch(ProcessorContext processorContext) {
          _collector.setContext(processorContext);
          Object batchId = processorContext.batchId;
          // since this processor type is a committer, this occurs in the commit phase
          List<TridentTuple> buffer = (List) processorContext.state[_context.getStateIndex()];
  
          // don't update unless there are tuples
          // this helps out with things like global partition persist, where multiple tasks may still
          // exist for this processor. Only want the global one to do anything
          // this is also a helpful optimization that state implementations don't need to manually do
          if (buffer.size() > 0) {
              Long txid = null;
              // this is to support things like persisting off of drpc stream, which is inherently unreliable
              // and won't have a tx attempt
              if (batchId instanceof TransactionAttempt) {
                  txid = ((TransactionAttempt) batchId).getTransactionId();
              }
              _state.beginCommit(txid);
              _updater.updateState(_state, buffer, _collector);
              _state.commit(txid);
          }
      }
  
      @Override
      public Factory getOutputFactory() {
          return _collector.getOutputFactory();
      }
  }