util.ExampleSocialMediaStormDeclarator.java Source code

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Here is the source code for util.ExampleSocialMediaStormDeclarator.java

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/////////////////////////////////////////////////////////////////////////
//
// \xa9 University of Southampton IT Innovation, 2014
//
// Copyright in this software belongs to IT Innovation Centre of
// Gamma House, Enterprise Road, Southampton SO16 7NS, UK.
//
// This software may not be used, sold, licensed, transferred, copied
// or reproduced in whole or in part in any manner or form or in or
// on any media by any person other than in accordance with the terms
// of the Licence Agreement supplied with the software, or otherwise
// without the prior written consent of the copyright owners.
//
// This software is distributed WITHOUT ANY WARRANTY, without even the
// implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
// PURPOSE, except where stated in the Licence Agreement supplied with
// the software.
//
//   Created By :   Vadim Krivcov
//   Created Date :   2014/02/09
//   Created for Project:   REVEAL
//
/////////////////////////////////////////////////////////////////////////
//
// Dependencies: None
//
/////////////////////////////////////////////////////////////////////////

package util;

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

// Import rabbitmq channel class
import com.rabbitmq.client.Channel;

// Import RabbitMq declarator
import io.latent.storm.rabbitmq.Declarator;

/**
 * Example Social Media Storm Declarator class (simple example without exchange
 * and routing keys). Will be passed to the main Social Media AMQP Spout and
 * will declare specified RabbitMQ queue. Mainly needed in case if Storm spout
 * would start to receive messages before they would be actually be sent
 * 
 * Documentation (no API, just an example of usage):
 * https://github.com/ppat/storm-rabbitmq/blob/master/README.md (search for
 * "Declarator")
 */
public class ExampleSocialMediaStormDeclarator implements Declarator {
    private String strExchange;
    private String strRoutingKey;
    private String strQueueName;
    private String strExchangeType;
    private boolean boolPersistence;

    /**
     * Main constructor
     * 
     * @param strExchange
     *            rabbitmq exchange value
     * @param strExchangeType
     *            rabbitmq exhange type (e.g. topic, direct etc)
     * @param strRoutingKey
     *            rabbitmq routing key
     * @param strQueueName
     *            rabbitmq queue name
     */
    public ExampleSocialMediaStormDeclarator(String strExchange, String strExchangeType, String strRoutingKey,
            String strQueueName, boolean boolPersistence) {
        this.strExchange = strExchange;
        this.strRoutingKey = strRoutingKey;
        this.strQueueName = strQueueName;
        this.strExchangeType = strExchangeType;
        this.boolPersistence = boolPersistence;
    }

    /**
     * Main RabbitMQ declaration method. Will use RabbitMQ channel reference.
     *
     * Rabbit MQ Channel API:
     * https://www.rabbitmq.com/releases/rabbitmq-java-client/v3.1.5/rabbitmq-
     * java-client-javadoc-3.1.5/ (search for "Channel")
     *
     * @param channel
     *            rabbitmq channel
     */
    @Override
    public void execute(Channel channel) {
        try {
            // Storm any possible arguments that could be passed
            Map<String, Object> args = new HashMap<>();

            /*
             * Declare the queue
             *
             * API:
             * http://www.rabbitmq.com/releases/rabbitmq-java-client/v1.7.0/
             * rabbitmq-java-client-javadoc-1.7.0/com/rabbitmq/client/Channel.
             * html#queueDeclare(java.lang.String, boolean, boolean, boolean,
             * boolean, java.util.Map))
             * 
             */
            channel.queueDeclare(this.strQueueName, true, false, false, args);

            /*
             * Declare the exchange
             *
             * API:
             * http://www.rabbitmq.com/releases/rabbitmq-java-client/v1.7.0/
             * rabbitmq-java-client-javadoc-1.7.0/com/rabbitmq/client/Channel.
             * html#exchangeDeclare(java.lang.String, java.lang.String, boolean)
             */
            channel.exchangeDeclare(this.strExchange, this.strExchangeType, this.boolPersistence);

            /*
             * Bind the queue
             *
             * API:
             * http://www.rabbitmq.com/releases/rabbitmq-java-client/v1.7.0/
             * rabbitmq-java-client-javadoc-1.7.0/com/rabbitmq/client/Channel.
             * html#queueBind(java.lang.String, java.lang.String,
             * java.lang.String)
             */
            channel.queueBind(this.strQueueName, this.strExchange, this.strRoutingKey);

            // Handle Exception and allow to continue
        } catch (Exception e) {
            System.err.println("Failed to execute RabbitMQ declarations. Details: " + e.getMessage());
            e.printStackTrace();
        }
    }
}