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A library of tools for interacting with RabbitMQ from Storm.

There is a newer version: 1.0.0

package io.latent.storm.rabbitmq;

import backtype.storm.spout.Scheme;
import backtype.storm.spout.SpoutOutputCollector;
import backtype.storm.task.TopologyContext;
import backtype.storm.topology.OutputFieldsDeclarer;
import backtype.storm.topology.base.BaseRichSpout;
import io.latent.storm.rabbitmq.config.ConsumerConfig;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.Collections;
import java.util.List;
import java.util.Map;

/**
 * A simple RabbitMQ spout that emits an anchored tuple stream (on the default stream). This can be used with
 * Storm's guaranteed message processing.
 * 
 * @author [email protected]
 */
public class RabbitMQSpout extends BaseRichSpout {
  private final MessageScheme scheme;
  private final Declarator declarator;

  private transient Logger logger;
  private transient RabbitMQConsumer consumer;
  private transient SpoutOutputCollector collector;

  public RabbitMQSpout(Scheme scheme) {
    this(MessageScheme.Builder.from(scheme), new Declarator.NoOp());
  }

  public RabbitMQSpout(Scheme scheme, Declarator declarator) {
    this(MessageScheme.Builder.from(scheme), declarator);
  }

  public RabbitMQSpout(MessageScheme scheme, Declarator declarator) {
    this.scheme = scheme;
    this.declarator = declarator;
  }

  @Override
  public void open(final Map config,
                   final TopologyContext context,
                   final SpoutOutputCollector spoutOutputCollector) {
    ConsumerConfig consumerConfig = ConsumerConfig.getFromStormConfig(config);
    ErrorReporter reporter = new ErrorReporter() {
      @Override
      public void reportError(Throwable error) {
        spoutOutputCollector.reportError(error);
      }
    };
    consumer = loadConsumer(declarator, reporter, consumerConfig);
    scheme.open(config, context);
    consumer.open();
    logger = LoggerFactory.getLogger(RabbitMQSpout.class);
    collector = spoutOutputCollector;
  }

  protected RabbitMQConsumer loadConsumer(Declarator declarator,
                                          ErrorReporter reporter,
                                          ConsumerConfig config) {
    return new RabbitMQConsumer(config.getConnectionConfig(),
                                config.getPrefetchCount(),
                                config.getQueueName(),
                                config.isRequeueOnFail(),
                                declarator,
                                reporter);
  }

  @Override
  public void close() {
    consumer.close();
    scheme.close();
    super.close();
  }

  @Override
  public void nextTuple() {
    Message message;
    while ((message = consumer.nextMessage()) != Message.NONE) {
      List