/**
* 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);
}