/*
* 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.flink.storm.wordcount.operators;
import org.apache.storm.task.OutputCollector;
import org.apache.storm.task.TopologyContext;
import org.apache.storm.topology.IRichBolt;
import org.apache.storm.topology.OutputFieldsDeclarer;
import org.apache.storm.tuple.Fields;
import org.apache.storm.tuple.Tuple;
import org.apache.storm.tuple.Values;
import java.util.HashMap;
import java.util.Map;
/**
* Implements the word counter that counts the occurrence of each unique word. The bolt takes a pair (input tuple
* schema: {@code <String,Integer>}) and sums the given word count for each unique word (output tuple schema:
* {@code <String,Integer>} ).
* <p>
* Same as {@link BoltCounterByName}, but accesses input attribute by index (instead of name).
*/
public class BoltCounter implements IRichBolt {
private static final long serialVersionUID = 399619605462625934L;
public static final String ATTRIBUTE_WORD = "word";
public static final String ATTRIBUTE_COUNT = "count";
private final HashMap<String, Count> counts = new HashMap<String, Count>();
private OutputCollector collector;
@SuppressWarnings("rawtypes")
@Override
public void prepare(final Map stormConf, final TopologyContext context, final OutputCollector collector) {
this.collector = collector;
}
@Override
public void execute(final Tuple input) {
final String word = input.getString(BoltTokenizer.ATTRIBUTE_WORD_INDEX);
Count currentCount = this.counts.get(word);
if (currentCount == null) {
currentCount = new Count();
this.counts.put(word, currentCount);
}
currentCount.count += input.getInteger(BoltTokenizer.ATTRIBUTE_COUNT_INDEX);
this.collector.emit(new Values(word, currentCount.count));
}
@Override
public void cleanup() {/* nothing to do */}
@Override
public void declareOutputFields(final OutputFieldsDeclarer declarer) {
declarer.declare(new Fields(ATTRIBUTE_WORD, ATTRIBUTE_COUNT));
}
@Override
public Map<String, Object> getComponentConfiguration() {
return null;
}
/**
* A counter helper to emit immutable tuples to the given stormCollector and avoid unnecessary object
* creating/deletion.
*/
private static final class Count {
public int count;
public Count() {/* nothing to do */}
}
}