nl.utwente.bigdata.bolts.FilterLanguageBolt.java Source code

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Here is the source code for nl.utwente.bigdata.bolts.FilterLanguageBolt.java

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/**
 * 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 nl.utwente.bigdata.bolts;

import java.util.Arrays;
import java.util.Map;
import org.apache.log4j.Logger;

import twitter4j.Status;
import backtype.storm.task.TopologyContext;
import backtype.storm.topology.BasicOutputCollector;
import backtype.storm.topology.OutputFieldsDeclarer;
import backtype.storm.topology.base.BaseBasicBolt;
import backtype.storm.tuple.Fields;
import backtype.storm.tuple.Tuple;

/**
 * Split to multiple language streams
 * @TODO: implement
 * 
 * @author Djuri Baars
 * @author Martijn Hensema
 * @package Assignment7 
 */
public class FilterLanguageBolt extends BaseBasicBolt {
    public static final Logger logger = Logger.getLogger(FilterLanguageBolt.class);
    private static final long serialVersionUID = -8526320899331924698L;
    private final String[] languages = new String[] { "en", "fr", "es", "it", "de", "nl" };

    @Override
    public void prepare(Map stormConf, TopologyContext context) {

    }

    @Override
    public void execute(Tuple tuple, BasicOutputCollector collector) {
        String lang = tuple.getStringByField("lang");
        Status status = (Status) tuple.getValueByField("tweet");

        if (Arrays.asList(this.languages).contains(status.getLang())) {
            collector.emit(status.getLang(), tuple.getValues());
        } else {
            //logger.info(lang + " not found");
        }

    }

    @Override
    public void declareOutputFields(OutputFieldsDeclarer declarer) {
        for (String lang : this.languages) {
            declarer.declareStream(lang, new Fields("tweet", "normalized_text", "lang"));
            logger.info("Filter language prepared for " + lang);
        }
    }

}