ResultHandler.java

package cz.cuni.mff.d3s.been.hostruntime;

import static cz.cuni.mff.d3s.been.cluster.Names.PERSISTENCE_QUEUE_NAME;

import java.io.IOException;

import org.codehaus.jackson.map.ObjectMapper;
import org.codehaus.jackson.map.ObjectReader;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.hazelcast.core.IQueue;

import cz.cuni.mff.d3s.been.cluster.context.ClusterContext;
import cz.cuni.mff.d3s.been.core.persistence.EntityCarrier;
import cz.cuni.mff.d3s.been.socketworks.SocketHandlerException;
import cz.cuni.mff.d3s.been.socketworks.oneway.ReadOnlyHandler;

/**
 * {@link HostRuntime}'s logic of handling
 * 
 * @author Radek Macha
 */
public class ResultHandler implements ReadOnlyHandler {
	private static final Logger log = LoggerFactory.getLogger(ResultHandler.class);

	private final IQueue<EntityCarrier> resultQueue;
	private final ObjectMapper objectMapper;
	private final ObjectReader resultReader;

	private ResultHandler(IQueue<EntityCarrier> resultQueue) {
		this.resultQueue = resultQueue;
		this.objectMapper = new ObjectMapper();
		this.resultReader = objectMapper.reader(EntityCarrier.class);
	}

	/**
	 * Create a result handler
	 * 
	 * @param ctx
	 *          Hazelcast context to create this handler under. Is used to load
	 *          distributed memory data structures, namely the queue containing
	 *          results.
	 * 
	 * @return A ready handler
	 */
	public static ReadOnlyHandler create(ClusterContext ctx) {
		final IQueue<EntityCarrier> resultQueue = ctx.getQueue(PERSISTENCE_QUEUE_NAME);
		return new ResultHandler(resultQueue);
	}

	@Override
	public void handle(String message) throws SocketHandlerException {
		log.debug("Unmarshalling result: {}", message);
		try {
			final EntityCarrier rc = resultReader.readValue(message);
			if (resultQueue.add(rc)) {
				log.debug("Queued result {}", rc.toString());
			} else {
				log.error("Could not put result {} to queue, delaying.", rc.toString());
				// TODO consider handling
			}
		} catch (IOException e) {
			log.error("Cannot deserialize result carrier:", e);
		}
	}
}