acromusashi.stream.example.bolt.JsonExtractBolt.java Source code

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Here is the source code for acromusashi.stream.example.bolt.JsonExtractBolt.java

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/**
* Copyright (c) Acroquest Technology Co, Ltd. All Rights Reserved.
* Please read the associated COPYRIGHTS file for more details.
*
* THE SOFTWARE IS PROVIDED BY Acroquest Technolog Co., Ltd.,
* WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
* BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDER BE LIABLE FOR ANY
* CLAIM, DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING
* OR DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES.
*/
package acromusashi.stream.example.bolt;

import java.io.IOException;
import java.text.MessageFormat;
import java.util.Map;

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

import acromusashi.stream.bolt.AmBaseBolt;
import acromusashi.stream.entity.StreamMessage;
import backtype.storm.task.TopologyContext;

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;

/**
 * ?JSON???Bolt<br/>
 *
 * @author kimura
 */
public class JsonExtractBolt extends AmBaseBolt {
    /** serialVersionUID */
    private static final long serialVersionUID = 4002032169715662295L;

    /** logger */
    private static final Logger logger = LoggerFactory.getLogger(JsonExtractBolt.class);

    /** ?? */
    protected String targetKey;

    /** Json?? */
    protected transient ObjectMapper mapper;

    /**
     * JSON???
     *
     * @param targetKey 
     */
    public JsonExtractBolt(String targetKey) {
        this.targetKey = targetKey;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void onPrepare(@SuppressWarnings("rawtypes") Map arg0, TopologyContext arg1) {
        this.mapper = new ObjectMapper();
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void onExecute(StreamMessage message) {
        String jsonStr = message.getBody().toString();

        JsonNode rootJson;
        try {
            // JsonNode???
            rootJson = this.mapper.readTree(jsonStr);
        } catch (IOException ex) {
            String logFormat = "Recived message is not valid. Skip message. : Message={0}";
            logger.warn(MessageFormat.format(logFormat, jsonStr), ex);
            return;
        }

        // JsonNode?????
        JsonNode valueJson = rootJson.get(this.targetKey);
        if (valueJson == null) {
            String logFormat = "Target Value is not exist. : TargetKey={0}, Message={1}";
            logger.warn(MessageFormat.format(logFormat, this.targetKey, jsonStr));
            return;
        }

        StreamMessage sendMessage = new StreamMessage();
        sendMessage.setBody(valueJson.asText());
        emitWithOnlyAnchor(sendMessage);
    }
}