com.ikanow.aleph2.storm.samples.bolts.SampleKafkaOutputBolt.java Source code

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Here is the source code for com.ikanow.aleph2.storm.samples.bolts.SampleKafkaOutputBolt.java

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/*******************************************************************************
 * Copyright 2015, The IKANOW Open Source Project.
 *
 * Licensed 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 com.ikanow.aleph2.storm.samples.bolts;

import java.io.IOException;
import java.util.Map;
import java.util.Optional;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.node.ObjectNode;
import com.ikanow.aleph2.data_model.interfaces.data_import.IEnrichmentModuleContext;

import backtype.storm.task.OutputCollector;
import backtype.storm.task.TopologyContext;
import backtype.storm.topology.OutputFieldsDeclarer;
import backtype.storm.topology.base.BaseRichBolt;
import backtype.storm.tuple.Fields;
import backtype.storm.tuple.Tuple;

/**
 * Output a jsonNode to the iEnrichmentStreamingTopology
 * 
 * @author Burch
 *
 */
public class SampleKafkaOutputBolt extends BaseRichBolt {

    private static final long serialVersionUID = 2023732900302096606L;
    private OutputCollector _collector;
    public static final Logger logger = LoggerFactory.getLogger(SampleKafkaOutputBolt.class);
    private IEnrichmentModuleContext context;

    public SampleKafkaOutputBolt() {
        //TODO get IEnrichmentModuleContext
    }

    @Override
    public void execute(Tuple tuple) {
        //this tuple contains 3 fields, keyA, keyB, message, push these into a jsonNodeObject and return                  
        if (tuple.size() == 3) {
            String keyA = tuple.getString(0);
            String keyB = tuple.getString(1);
            String message = tuple.getString(2);

            try {
                JsonNode output_node = createJsonNode(keyA, keyB, message);
                //TODO send to service we want or is there some json output?
                long id = 0; //TODO what is this suppose to be?
                context.emitImmutableObject(id, output_node, Optional.empty(), Optional.empty(), Optional.empty());
                _collector.ack(tuple);
            } catch (Exception e) {
                logger.error("Error parsing json", e);
                //probably ack a failure
                _collector.fail(tuple);
            }
        } else {
            logger.error("tuple size was not 3");
            //probably ack a failure
            _collector.fail(tuple);
        }
    }

    private JsonNode createJsonNode(String keyA, String keyB, String message)
            throws JsonProcessingException, IOException {
        ObjectNode objNode = (ObjectNode) new ObjectMapper().readTree(message);
        objNode.put("modifiedKeyA", keyA);
        objNode.put("modifiedKeyB", keyB);
        return objNode;
    }

    @SuppressWarnings("rawtypes")
    @Override
    public void prepare(Map stormConf, TopologyContext context, OutputCollector collector) {
        _collector = collector;
    }

    @Override
    public void declareOutputFields(OutputFieldsDeclarer declarer) {
        //we don't emit from this bolt ever so we have no output fields
        declarer.declare(new Fields());
    }

}