MetricsConsumerBolt.java

package backtype.storm.metric;

import backtype.storm.Config;
import backtype.storm.metric.api.IMetricsConsumer;
import backtype.storm.task.IBolt;
import backtype.storm.task.IErrorReporter;
import backtype.storm.task.OutputCollector;
import backtype.storm.task.TopologyContext;
import backtype.storm.tuple.Tuple;
import java.util.Collection;
import java.util.Map;

public class MetricsConsumerBolt implements IBolt {
	IMetricsConsumer _metricsConsumer;
	String _consumerClassName;
	OutputCollector _collector;
	Object _registrationArgument;

	public MetricsConsumerBolt(String consumerClassName,
			Object registrationArgument) {
		_consumerClassName = consumerClassName;
		_registrationArgument = registrationArgument;
	}

	@Override
	public void prepare(Map stormConf, TopologyContext context,
			OutputCollector collector) {
		try {
			_metricsConsumer = (IMetricsConsumer) Class.forName(
					_consumerClassName).newInstance();
		} catch (Exception e) {
			throw new RuntimeException(
					"Could not instantiate a class listed in config under section "
							+ Config.TOPOLOGY_METRICS_CONSUMER_REGISTER
							+ " with fully qualified name "
							+ _consumerClassName, e);
		}
		_metricsConsumer.prepare(stormConf, _registrationArgument, context,
				(IErrorReporter) collector);
		_collector = collector;
	}

	@Override
	public void execute(Tuple input) {
		_metricsConsumer.handleDataPoints(
				(IMetricsConsumer.TaskInfo) input.getValue(0),
				(Collection) input.getValue(1));
		_collector.ack(input);
	}

	@Override
	public void cleanup() {
		_metricsConsumer.cleanup();
	}

}