RepresentationVersionRemovedMessageProcessor.java

package eu.europeana.cloud.service.dls.listeners;

import eu.europeana.cloud.service.dls.solr.SolrDAO;
import eu.europeana.cloud.service.mcs.messages.AbstractMessage;
import eu.europeana.cloud.service.mcs.messages.RemoveRepresentationVersionMessage;
import java.io.IOException;
import org.apache.commons.lang.StringUtils;
import org.apache.solr.client.solrj.SolrServerException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

/**
 * Processor that processes messages about removing a
 * {@link eu.europeana.cloud.common.model.Representation representation} version
 * from a certain {@link eu.europeana.cloud.common.model.Record record}.
 * 
 * It processes messages with
 * <code>records.representations.versions.deleteVersion</code> routing key.
 * Message text should be a representation version (directly sent value).
 * Representation version id uniquely identifies {@link Representation
 * representation} in the whole system, so it is know from which
 * {@link eu.europeana.cloud.common.model.Record record} to remove it.
 * 
 * After processing properly formed message, processor calls
 * {@link eu.europeana.cloud.service.dls.solr.SolrDAO#removeRepresentationVersion(String)}
 * so that Solr index is updated ({@link eu.europeana.cloud.common.model.Record
 * record} will not hold this representation version in updated index).
 * 
 * If message is malformed, information about error is logged and no call to
 * {@link eu.europeana.cloud.service.dls.solr.SolrDAO} is performed. If call to
 * {@link eu.europeana.cloud.service.dls.solr.SolrDAO} fails, an information is
 * also logged.
 * 
 * Messages for this processor are produced by
 * <code>eu.europeana.cloud.service.mcs.persistent.SolrRepresentationIndexer.removeRepresentationVersion(String)}</code>
 * method in MCS.
 */
@Component
public class RepresentationVersionRemovedMessageProcessor implements
	MessageProcessor<RemoveRepresentationVersionMessage> {

    private static final Logger LOGGER = LoggerFactory
	    .getLogger(RepresentationVersionRemovedMessageProcessor.class);

    @Autowired
    SolrDAO solrDao;

    @Override
    public void processMessage(RemoveRepresentationVersionMessage message) {
        String messageText = message.getPayload();
        
        if (messageText == null || messageText.isEmpty()) {
            LOGGER.error("Message has empty body.");
            return;
        }

        String versionId = messageText;

        if (StringUtils.isBlank(versionId)) {
            LOGGER.error("Required parameter version id is empty.");
            return;
        }

        try {
            solrDao.removeRepresentationVersion(versionId);
        } catch (SolrServerException | IOException ex) {
            LOGGER.error("Cannot remove representation from solr.", ex);
        }

    }
}