Metacat

/**

 *  '$RCSfile$'

 *    Purpose: A class that gets Accession Number, check for uniqueness

 *             and register it into db

 *  Copyright: 2000 Regents of the University of California and the

 *             National Center for Ecological Analysis and Synthesis

 *    Authors: Jivka Bojilova, Matt Jones

 *

 *   '$Author: leinfelder $'

 *     '$Date: 2011-11-02 20:40:12 -0700 (Wed, 02 Nov 2011) $'

 * '$Revision: 6595 $'

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 */

package edu.ucsb.nceas.metacat.index;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.InputStream;

import java.util.ArrayList;

import java.util.Calendar;

import java.util.List;

import org.apache.commons.logging.Log;

import org.apache.commons.logging.LogFactory;

import org.dataone.service.exceptions.ServiceFailure;

import org.dataone.service.types.v1.Event;

import org.dataone.service.types.v1.Identifier;

import org.dataone.service.types.v1.SystemMetadata;

import com.hazelcast.core.IMap;

import com.hazelcast.core.ISet;

import com.hazelcast.core.ItemEvent;

import com.hazelcast.core.ItemListener;

import edu.ucsb.nceas.metacat.common.index.event.IndexEvent;

import edu.ucsb.nceas.metacat.index.event.EventlogFactory;

public class SystemMetadataEventListener implements ItemListener<SystemMetadata> {

	private static Log log = LogFactory.getLog(SystemMetadataEventListener.class);

	private SolrIndex solrIndex = null;

    /**

     * Default constructor - caller needs to initialize manually

     * @see setSolrIndex()

     * @see start()

     */

    public SystemMetadataEventListener() {

    }

    /**

     * Sets the SolrIndex instance and initializes the listener 

     * @param solrIndex

     */

    public SystemMetadataEventListener(SolrIndex solrIndex) {

    	this.solrIndex = solrIndex;

    	try {

			start();

		} catch (Exception e) {

			log.error(e.getMessage(), e);

		}

    }

    /**

     * Get the SolrIndex that this listener communicates with

     * @return a SolrIndex instance that indexes the content being listened to

     */

    public SolrIndex getSolrIndex() {

		return solrIndex;

	}

    /**

     * Set the SolrIndex instance that the listener modifies

     * @param solrIndex

     */

	public void setSolrIndex(SolrIndex solrIndex) {

		this.solrIndex = solrIndex;

	}

	/**

     * Registers this instance as a system metadata map event listener

	 * @throws ServiceFailure 

	 * @throws FileNotFoundException 

     */

    public void start() throws FileNotFoundException, ServiceFailure {

        // get shared structures and add listener

        IMap<Identifier, String> objectPathMap = DistributedMapsFactory.getObjectPathMap();

        ISet<SystemMetadata> indexQueue = DistributedMapsFactory.getIndexQueue();

        indexQueue.addItemListener(this, true);

        log.info("System Metadata size: " + indexQueue.size());

        log.info("Object path size:" + objectPathMap.size());

    }

    /**

     * Removes this instance as a system metadata map event listener

     * @throws ServiceFailure 

     * @throws FileNotFoundException 

     */

    public void stop() throws FileNotFoundException, ServiceFailure {

    	log.info("stopping index entry listener...");

    	DistributedMapsFactory.getIndexQueue().removeItemListener(this);

    }

    /**

     * Get the obsoletes chain of the specified id. The returned list doesn't include

     * the specified id itself. The newer version has the lower index number in the list.

     * Empty list will be returned if there is no document to be obsoleted by this id.

     * @param id

     * @return

     * @throws ServiceFailure

     * @throws FileNotFoundException 

     */

    private List<String> getObsoletes(String id) throws FileNotFoundException, ServiceFailure {

        List<String> obsoletes = new ArrayList<String>();

        while (id != null) {

            SystemMetadata metadata = DistributedMapsFactory.getSystemMetadata(id);

            id = null;//set it to be null in order to stop the while loop if the id can't be assinged to a new value in the following code.

            if(metadata != null) {

                Identifier identifier = metadata.getObsoletes();

                if(identifier != null && identifier.getValue() != null && !identifier.getValue().trim().equals("")) {

                    obsoletes.add(identifier.getValue());

                    id = identifier.getValue();

                } 

            } 

        }

        return obsoletes;

    }

	public void itemRemoved(ItemEvent<SystemMetadata> entryEvent) {

		// remove from the index

		Identifier pid = entryEvent.getItem().getIdentifier();

		if(pid != null) {

		    try {

	            solrIndex.remove(pid.getValue());

	        } catch (Exception e) {

	            String error = "SystemMetadataEventListener.itemRemoved - couldn't remove the index for the pid "+pid.getValue()+" since "+e.getMessage();

	            SystemMetadata systemMetadata = entryEvent.getItem();

	            writeEventLog(systemMetadata, pid, error);

	            log.error(error, e);

	        }

		}

	}

	public void itemAdded(ItemEvent<SystemMetadata> entryEvent) {

	    //System.out.println("===================================calling entryUpdated method ");

	    log.info("===================================calling SystemMetadataEventListener.itemAdded method ");

		// add to the index

		Identifier pid = entryEvent.getItem().getIdentifier();

		//System.out.println("===================================update the document "+pid.getValue());

		log.info("===================================adding the document "+pid.getValue());

		SystemMetadata systemMetadata = entryEvent.getItem();

		if(systemMetadata == null) {

		    writeEventLog(systemMetadata, pid, "SystemMetadataEventListener.itemAdded -could not get the SystemMetadata");

		    return;

		}

		Identifier obsoletes = systemMetadata.getObsoletes();

		List<String> obsoletesChain = null;

		if (obsoletes != null) {

		    try {

				obsoletesChain = getObsoletes(pid.getValue());

			} catch (Exception e) {

			    String error = "SystemMetadataEventListener.itemAdded -could not look up revision history " + e.getMessage();

			    writeEventLog(systemMetadata, pid, error);

	            log.error(error, e);

	            return;

			}

		}

		String objectPath = null;

		try {

			objectPath = DistributedMapsFactory.getObjectPathMap().get(pid);

		} catch (Exception e) {

		    String error = "SystemMetadataEventListener.itemAdded - could not look up object path" + e.getMessage();

		    writeEventLog(systemMetadata, pid, error);

			log.error(error, e);

			return;

		}

		if(objectPath != null) {

		    InputStream data = null;

	        try {

	            data = new FileInputStream(objectPath);

	            solrIndex.update(pid.getValue(), obsoletesChain, systemMetadata, data);

	        } catch (Exception e) {

	            String error = "SystemMetadataEventListener.itemAdded - could not comit the index into the solr server since " + e.getMessage();

	            writeEventLog(systemMetadata, pid, error);

	            log.error(error, e);

	        }

		}

	}

	private void writeEventLog(SystemMetadata systemMetadata, Identifier pid, String error) {

	    IndexEvent event = new IndexEvent();

        event.setIdentifier(pid);

	    event.setDate(Calendar.getInstance().getTime());

	    String action = null;

	    if (systemMetadata == null ) {

	        action = Event.CREATE.xmlValue();

            event.setAction(Event.CREATE);

	    }

	    else if(systemMetadata.getArchived() || systemMetadata.getObsoletedBy() != null) {

            action = Event.DELETE.xmlValue();

            event.setAction(Event.DELETE);

        } else {

            action = Event.CREATE.xmlValue();

            event.setAction(Event.CREATE);

        }

        event.setDescription("Failed to "+action+"the solr index for the id "+pid.getValue()+" since "+error);

        try {

            EventlogFactory.createIndexEventLog().write(event);

        } catch (Exception ee) {

            log.error("SolrIndex.insertToIndex - IndexEventLog can't log the index inserting event :"+ee.getMessage());

        }

	}

}