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.task.TopologyContext;
  import backtype.storm.tuple.Fields;
  import java.io.Serializable;
  import java.util.List;
  import java.util.Map;
  import storm.trident.operation.TridentCollector;
  import storm.trident.topology.TransactionAttempt;
  
  /**
   * This interface defines a transactional spout that reads its tuples from a partitioned set of 
   * brokers. It automates the storing of metadata for each partition to ensure that the same batch
   * is always emitted for the same transaction id. The partition metadata is stored in Zookeeper.
   */
  public interface IPartitionedTridentSpout<Partitions, Partition extends ISpoutPartition, T> extends ITridentDataSource {
      public interface Coordinator<Partitions> {
          /**
           * Return the partitions currently in the source of data. The idea is
           * is that if a new partition is added and a prior transaction is replayed, it doesn't
           * emit tuples for the new partition because it knows what partitions were in 
           * that transaction.
           */
          Partitions getPartitionsForBatch();
  
          boolean isReady(long txid);
  
          void close();
      }
  
      public interface Emitter<Partitions, Partition extends ISpoutPartition, X> {
  
          List<Partition> getOrderedPartitions(Partitions allPartitionInfo);
  
          /**
           * Emit a batch of tuples for a partition/transaction that's never been emitted before.
           * Return the metadata that can be used to reconstruct this partition/batch in the future.
           */
          X emitPartitionBatchNew(TransactionAttempt tx, TridentCollector collector, Partition partition, X lastPartitionMeta);
  
          /**
           * This method is called when this task is responsible for a new set of partitions. Should be used
           * to manage things like connections to brokers.
           */
          void refreshPartitions(List<Partition> partitionResponsibilities);
  
          /**
           * Emit a batch of tuples for a partition/transaction that has been emitted before, using
           * the metadata created when it was first emitted.
           */
          void emitPartitionBatch(TransactionAttempt tx, TridentCollector collector, Partition partition, X partitionMeta);
  
          void close();
      }
  
      Coordinator<Partitions> getCoordinator(Map conf, TopologyContext context);
  
      Emitter<Partitions, Partition, T> getEmitter(Map conf, TopologyContext context);
      
      Map<String, Object> getComponentConfiguration();
      Fields getOutputFields();
  }
  