eco-heron-examples/src/java/org/apache/heron/examples/eco/TestNameCounter.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.heron.examples.eco;

import java.util.HashMap;
import java.util.Map;

import org.apache.heron.api.bolt.BaseBasicBolt;
import org.apache.heron.api.bolt.BasicOutputCollector;
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.Tuple;

import static org.apache.heron.api.utils.Utils.tuple;

@SuppressWarnings({"serial", "rawtypes"})
public class TestNameCounter extends BaseBasicBolt {

  private Map<String, Integer> counts;

  @Override
  public void prepare(Map map, TopologyContext topologyContext) {
    counts = new HashMap<>();
  }


  protected String getTupleValue(Tuple t, int idx) {
    return (String) t.getValues().get(idx);
  }

  public void execute(Tuple input, BasicOutputCollector collector) {
    String word = getTupleValue(input, 0);
    int count = 0;
    if (counts.containsKey(word)) {
      count = counts.get(word);
    }
    count++;
    counts.put(word, count);
    collector.emit(tuple(word, count));
  }

  public void cleanup() {

  }

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

}