examples/storm-starter/src/jvm/org/apache/storm/starter/WordCountTopology.java

/**
 * 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.starter;

import java.util.HashMap;
import java.util.Map;
import org.apache.storm.starter.spout.RandomSentenceSpout;
import org.apache.storm.task.ShellBolt;
import org.apache.storm.topology.BasicOutputCollector;
import org.apache.storm.topology.ConfigurableTopology;
import org.apache.storm.topology.IRichBolt;
import org.apache.storm.topology.OutputFieldsDeclarer;
import org.apache.storm.topology.TopologyBuilder;
import org.apache.storm.topology.base.BaseBasicBolt;
import org.apache.storm.tuple.Fields;
import org.apache.storm.tuple.Tuple;
import org.apache.storm.tuple.Values;

/**
 * This topology demonstrates Storm's stream groupings and multilang
 * capabilities.
 */
public class WordCountTopology extends ConfigurableTopology {
    public static void main(String[] args) throws Exception {
        ConfigurableTopology.start(new WordCountTopology(), args);
    }

    @Override
    protected int run(String[] args) throws Exception {

        TopologyBuilder builder = new TopologyBuilder();

        builder.setSpout("spout", new RandomSentenceSpout(), 5);

        builder.setBolt("split", new SplitSentence(), 8).shuffleGrouping("spout");
        builder.setBolt("count", new WordCount(), 12).fieldsGrouping("split", new Fields("word"));

        conf.setDebug(true);

        String topologyName = "word-count";

        conf.setNumWorkers(3);

        if (args != null && args.length > 0) {
            topologyName = args[0];
        }
        return submit(topologyName, conf, builder);
    }

    public static class SplitSentence extends ShellBolt implements IRichBolt {

        public SplitSentence() {
            super("python", "splitsentence.py");
        }

        @Override
        public void declareOutputFields(OutputFieldsDeclarer declarer) {
            declarer.declare(new Fields("word"));
        }

        @Override
        public Map<String, Object> getComponentConfiguration() {
            return null;
        }
    }

    public static class WordCount extends BaseBasicBolt {
        Map<String, Integer> counts = new HashMap<String, Integer>();

        @Override
        public void execute(Tuple tuple, BasicOutputCollector collector) {
            String word = tuple.getString(0);
            Integer count = counts.get(word);
            if (count == null) {
                count = 0;
            }
            count++;
            counts.put(word, count);
            collector.emit(new Values(word, count));
        }

        @Override
        public void declareOutputFields(OutputFieldsDeclarer declarer) {
            declarer.declare(new Fields("word", "count"));
        }
    }
}