| /** |
| * 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 org.apache.storm.topology; |
| |
| import static org.apache.storm.spout.CheckPointState.Action; |
| import static org.apache.storm.spout.CheckpointSpout.CHECKPOINT_STREAM_ID; |
| |
| import java.util.Map; |
| |
| import org.apache.storm.task.OutputCollector; |
| import org.apache.storm.task.TopologyContext; |
| import org.apache.storm.tuple.Tuple; |
| import org.apache.storm.tuple.Values; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| /** |
| * Wraps {@link IRichBolt} and forwards checkpoint tuples in a stateful topology. |
| * <p> |
| * When a storm topology contains one or more {@link IStatefulBolt} all non-stateful bolts are wrapped in {@link CheckpointTupleForwarder} |
| * so that the checkpoint tuples can flow through the entire topology DAG. |
| * </p> |
| */ |
| public class CheckpointTupleForwarder extends BaseStatefulBoltExecutor { |
| private static final Logger LOG = LoggerFactory.getLogger(CheckpointTupleForwarder.class); |
| private final IRichBolt bolt; |
| |
| public CheckpointTupleForwarder(IRichBolt bolt) { |
| this.bolt = bolt; |
| } |
| |
| @Override |
| public void prepare(Map<String, Object> topoConf, TopologyContext context, OutputCollector outputCollector) { |
| init(context, new AnchoringOutputCollector(outputCollector)); |
| bolt.prepare(topoConf, context, collector); |
| } |
| |
| @Override |
| public void cleanup() { |
| bolt.cleanup(); |
| } |
| |
| @Override |
| public void declareOutputFields(OutputFieldsDeclarer declarer) { |
| bolt.declareOutputFields(declarer); |
| declareCheckpointStream(declarer); |
| } |
| |
| @Override |
| public Map<String, Object> getComponentConfiguration() { |
| return bolt.getComponentConfiguration(); |
| } |
| |
| /** |
| * Forwards the checkpoint tuple downstream. |
| * |
| * @param checkpointTuple the checkpoint tuple |
| * @param action the action (prepare, commit, rollback or initstate) |
| * @param txid the transaction id. |
| */ |
| @Override |
| protected void handleCheckpoint(Tuple checkpointTuple, Action action, long txid) { |
| collector.emit(CHECKPOINT_STREAM_ID, checkpointTuple, new Values(txid, action)); |
| collector.ack(checkpointTuple); |
| } |
| |
| /** |
| * Hands off tuple to the wrapped bolt to execute. |
| * |
| * <p> |
| * Right now tuples continue to get forwarded while waiting for checkpoints to arrive on other streams after checkpoint arrives on one |
| * of the streams. This can cause duplicates but still at least once. |
| * </p> |
| * |
| * @param input the input tuple |
| */ |
| @Override |
| protected void handleTuple(Tuple input) { |
| bolt.execute(input); |
| } |
| } |