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.state;
  
  /**
   * There's 3 different kinds of state:
   * 
   * 1. non-transactional: ignores commits, updates are permanent. no rollback. a cassandra incrementing state would be like this 2. repeat-transactional:
   * idempotent as long as all batches for a txid are identical 3. opaque-transactional: the most general kind of state. updates are always done based on the
   * previous version of the value if the current commit = latest stored commit Idempotent even if the batch for a txid can change.
   * 
   * repeat transactional is idempotent for transactional spouts opaque transactional is idempotent for opaque or transactional spouts
   * 
   * Trident should log warnings when state is idempotent but updates will not be idempotent because of spout
   */
  // retrieving is encapsulated in Retrieval interface
  public interface State {
      void beginCommit(Long txid); // can be null for things like partitionPersist occuring off a DRPC stream
  
      void commit(Long txid);
  }
  