stock84885customer.CustomerQueryController.java Source code

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Here is the source code for stock84885customer.CustomerQueryController.java

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package stock84885customer;

import com.rabbitmq.client.AMQP;
import com.rabbitmq.client.Channel;
import com.rabbitmq.client.Connection;
import com.rabbitmq.client.ConnectionFactory;
import com.rabbitmq.client.Consumer;
import com.rabbitmq.client.DefaultConsumer;
import com.rabbitmq.client.Envelope;
import com.rabbitmq.client.MessageProperties;
import core.Configuration;
import core.ILogger;
import java.io.IOException;
import java.util.concurrent.TimeoutException;

/**
 *
 * @author dario
 */
public class CustomerQueryController {

    private Channel queryChannel;
    private Channel queryResultChannel;
    private Connection connection;
    private Consumer queryResultsConsumer;
    private final ConnectionFactory connFactory;
    private final ILogger logger;
    private final String hostName;
    private final String name;
    private final String queryExchangeName;
    private final String queryResultsExchangeName;
    private String queryResultsQueueName;

    public CustomerQueryController(int id, Configuration config, ILogger logger) {
        connFactory = new ConnectionFactory();
        this.logger = logger;
        hostName = config.getProperty(Configuration.CUSTOMER_QUERY_HOSTNAME);
        name = "Customer-" + id;
        queryExchangeName = config.getProperty(Configuration.QUERIES_EXCHANGE_NAME);
        queryResultsExchangeName = config.getProperty(Configuration.QUERIES_RESULTS_EXCHANGE_NAME);
    }

    public void run() throws IOException, TimeoutException {
        try {
            connFactory.setHost(hostName);
            connection = connFactory.newConnection();
            initQueryChannel();
            initQueryResultChannel();
            sendQuery();
            queryResultChannel.basicConsume(queryResultsQueueName, false, queryResultsConsumer);
        } catch (IOException | TimeoutException e) {
            releaseNetworkResources();
            throw e;
        }
    }

    private void initQueryChannel() throws IOException {
        queryChannel = connection.createChannel();
        queryChannel.queueDeclare(queryExchangeName, true, //Passive declaration
                false, //Non-durable queue
                false, //Non-exclusive queue
                null //No arguments
        );
    }

    private void initQueryResultChannel() throws IOException {
        queryResultChannel = connection.createChannel();
        queryResultChannel.exchangeDeclare(queryResultsExchangeName, "direct");
        queryResultsQueueName = queryResultChannel.queueDeclare().getQueue();
        queryResultChannel.queueBind(queryResultsQueueName, queryResultsExchangeName, name);
        queryResultsConsumer = new DefaultConsumer(queryResultChannel) {
            @Override
            public void handleDelivery(String consumerTag, Envelope envelope, AMQP.BasicProperties properties,
                    byte[] body) throws IOException {
                try {
                    String result = new String(body, "UTF-8");
                    logger.trace(name + " received query result: " + result);
                    releaseNetworkResources();
                } catch (Exception ex) {
                    logger.error(ex.toString());
                }
            }
        };
    }

    private void releaseNetworkResources() throws IOException, TimeoutException {
        if (queryChannel != null) {
            queryChannel.close();
            queryChannel = null;
        }
        if (queryResultChannel != null) {
            queryResultChannel.close();
            queryResultChannel = null;
        }
        if (connection != null) {
            connection.close();
            connection = null;
        }
    }

    private void sendQuery() throws IOException {
        queryChannel.basicPublish("", queryExchangeName, MessageProperties.PERSISTENT_TEXT_PLAIN, name.getBytes());
    }

}