| /** |
| * 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.heron.examples.eco; |
| |
| import java.util.Map; |
| import java.util.concurrent.ThreadLocalRandom; |
| |
| import org.apache.heron.api.spout.BaseRichSpout; |
| import org.apache.heron.api.spout.SpoutOutputCollector; |
| import org.apache.heron.api.state.State; |
| import org.apache.heron.api.topology.IStatefulComponent; |
| import org.apache.heron.api.topology.OutputFieldsDeclarer; |
| import org.apache.heron.api.topology.TopologyContext; |
| import org.apache.heron.api.tuple.Fields; |
| import org.apache.heron.api.tuple.Values; |
| |
| import backtype.storm.utils.Utils; |
| |
| public class StatefulRandomIntSpout extends BaseRichSpout |
| implements IStatefulComponent<String, Integer> { |
| private SpoutOutputCollector spoutOutputCollector; |
| private State<String, Integer> count; |
| |
| public StatefulRandomIntSpout() { |
| } |
| |
| // Generates a random integer between 1 and 100 |
| private int randomInt() { |
| return ThreadLocalRandom.current().nextInt(1, 101); |
| } |
| |
| // These two methods are required to implement the IStatefulComponent interface |
| @Override |
| public void preSave(String checkpointId) { |
| System.out.println(String.format("Saving spout state at checkpoint %s", checkpointId)); |
| } |
| |
| @Override |
| public void initState(State<String, Integer> state) { |
| count = state; |
| } |
| |
| // These three methods are required to extend the BaseRichSpout abstract class |
| @Override |
| public void open(Map<String, Object> map, TopologyContext ctx, SpoutOutputCollector collector) { |
| spoutOutputCollector = collector; |
| } |
| |
| @Override |
| public void declareOutputFields(OutputFieldsDeclarer declarer) { |
| declarer.declare(new Fields("random-int")); |
| } |
| |
| @Override |
| public void nextTuple() { |
| Utils.sleep(2000); |
| int randomInt = randomInt(); |
| System.out.println("Emitting Value: " + randomInt); |
| spoutOutputCollector.emit(new Values(randomInt)); |
| } |
| } |
| |