Metacat

/**

 *  '$RCSfile$'

 *    Purpose: Implements a service for managing a Hazelcast cluster member

 *  Copyright: 2011 Regents of the University of California and the

 *             National Center for Ecological Analysis and Synthesis

 *    Authors: Christopher Jones

 * 

 *   '$Author: leinfelder $'

 *     '$Date: 2011-09-16 16:42:20 -0700 (Fri, 16 Sep 2011) $'

 * '$Revision: 6451 $'

 *

 * 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.dataone.hazelcast;

import org.apache.log4j.Logger;

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

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

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

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

import com.hazelcast.client.HazelcastClient;

import com.hazelcast.config.Config;

import com.hazelcast.config.FileSystemXmlConfig;

import com.hazelcast.core.EntryEvent;

import com.hazelcast.core.EntryListener;

import com.hazelcast.core.Hazelcast;

import com.hazelcast.core.IMap;

import com.hazelcast.core.InstanceEvent;

import com.hazelcast.core.InstanceListener;

import com.hazelcast.core.Member;

import com.hazelcast.partition.Partition;

import com.hazelcast.partition.PartitionService;

import edu.ucsb.nceas.metacat.IdentifierManager;

import edu.ucsb.nceas.metacat.McdbDocNotFoundException;

import edu.ucsb.nceas.metacat.dataone.CNReplicationTask;

import edu.ucsb.nceas.metacat.dataone.D1NodeService;

import edu.ucsb.nceas.metacat.properties.PropertyService;

import edu.ucsb.nceas.metacat.shared.BaseService;

import edu.ucsb.nceas.metacat.shared.ServiceException;

import edu.ucsb.nceas.utilities.PropertyNotFoundException;

/**

 * The Hazelcast service enables Metacat as a Hazelcast cluster member

 */

public class HazelcastService extends BaseService

  implements InstanceListener, EntryListener<Identifier, SystemMetadata> {

  /* The instance of the logging class */

  private static Logger logMetacat = Logger.getLogger(HazelcastService.class);

  /* The singleton instance of the hazelcast service */

  private static HazelcastService hzService = null;

  /* The Hazelcast configuration */

  private Config hzConfig;

  /* The instance of the Hazelcast client */

  private HazelcastClient hzClient;

  /* The name of the DataONE Hazelcast cluster group */

  private String groupName;

  /* The name of the DataONE Hazelcast cluster password */

  private String groupPassword;

  /* The name of the DataONE Hazelcast cluster IP addresses */

  private String addressList;

  /* The name of the node map */

  private String nodeMap;

  /* The name of the system metadata map */

  private String systemMetadataMap;

  /* The Hazelcast distributed task id generator namespace */

  private String taskIds;

  /* The Hazelcast distributed system metadata map */

  private IMap<NodeReference, Node> nodes;

  /* The Hazelcast distributed system metadata map */

  private IMap<Identifier, SystemMetadata> systemMetadata;

  /* The Hazelcast distributed pending replication tasks map*/

  private IMap<String, CNReplicationTask> pendingReplicationTasks;

  /*

   * Constructor: Creates an instance of the hazelcast service. Since

   * this uses a singleton pattern, use getInstance() to gain the instance.

   */

  private HazelcastService() {

    super();

    _serviceName="HazelcastService";

    try {

      init();

    } catch (ServiceException se) {

      logMetacat.error("There was a problem creating the HazelcastService. " +

                       "The error message was: " + se.getMessage());

    }

  }

  /**

   *  Get the instance of the HazelcastService that has been instantiated,

   *  or instantiate one if it has not been already.

   *

   * @return hazelcastService - The instance of the hazelcast service

   */

  public static HazelcastService getInstance(){

    if ( hzService == null ) {

      hzService = new HazelcastService();

    }

    return hzService;

  }

  /**

   * Initializes the Hazelcast service

   */

  public void init() throws ServiceException {

    logMetacat.debug("HazelcastService.doRefresh() called.");

    try {

    	String configFileName = PropertyService.getProperty("dataone.hazelcast.configFilePath");

//    	System.setProperty("hazelcast.config", configFileName);

		Config config = new FileSystemXmlConfig(configFileName);

		Hazelcast.init(config);

    } catch (Exception e) {

      String msg = e.getMessage();

      logMetacat.error(msg);

      throw new ServiceException(msg);

    }

    // Get configuration properties on instantiation

    try {

      groupName = 

        PropertyService.getProperty("dataone.hazelcast.processCluster.groupName");

      groupPassword = 

        PropertyService.getProperty("dataone.hazelcast.processCluster.password");

      addressList = 

        PropertyService.getProperty("dataone.hazelcast.processCluster.instances");

      nodeMap = 

        PropertyService.getProperty("dataone.hazelcast.processCluster.nodesMap");

      systemMetadataMap = 

        PropertyService.getProperty("dataone.hazelcast.storageCluster.systemMetadataMap");

      // Become a DataONE-process cluster client

      //TODO: where should this be?

//      String[] addresses = addressList.split(",");

//      hzClient = 

//        HazelcastClient.newHazelcastClient(this.groupName, this.groupPassword, addresses);

//      nodes = hzClient.getMap(nodeMap);

//      pendingReplicationTasks = hzClient.getMap(pendingTasksQueue);

      // Get a reference to the shared system metadata map as a cluster member

      systemMetadata = Hazelcast.getMap(systemMetadataMap);

      // Listen for changes to the system metadata map

      systemMetadata.addEntryListener(this, true);

    } catch (PropertyNotFoundException e) {

      String msg = "Couldn't find Hazelcast properties for the DataONE clusters. " +

        "The error message was: " + e.getMessage();

      logMetacat.error(msg);

    }

  }

  public IMap<Identifier,SystemMetadata> getSystemMetadataMap() {

	  return systemMetadata;

  }

  public IMap<String,CNReplicationTask> getPendingReplicationTasks() {

	  return pendingReplicationTasks;

  }

  /**

   * Indicate whether or not this service is refreshable.

   *

   * @return refreshable - the boolean refreshable status

   */

  public boolean refreshable() {

    // TODO: Determine the consequences of restarting the Hazelcast instance

    // Set this to true if it's okay to drop from the cluster, lose the maps,

    // and start back up again

    return false;

  }

  /**

   * Stop the HazelcastService. When stopped, the service will no longer

   * respond to requests.

   */

  public void stop() throws ServiceException {

    Hazelcast.getLifecycleService().shutdown();

  }

  /**

   * Listen for new Hazelcast member events

   */

  @Override

  public void instanceCreated(InstanceEvent event) {

    logMetacat.info("New Hazelcast instance created: " +

      event.getInstance().getId() + ", " +

      event.getInstance().getInstanceType());

  }

  @Override

  public void instanceDestroyed(InstanceEvent event) {

    logMetacat.info("Hazelcast instance removed: " +

        event.getInstance().getId() + ", " +

        event.getInstance().getInstanceType());

  }

  /**

   * Refresh the Hazelcast service by restarting it

   */

  @Override

  protected void doRefresh() throws ServiceException {

    // TODO: verify that the correct config file is still used

    Hazelcast.getLifecycleService().restart();

  }

  /**

	 * Implement the EntryListener interface for Hazelcast, reponding to entry

	 * added events in the hzSystemMetadata map. Evaluate the entry and create

	 * CNReplicationTasks as appropriate (for DATA, METADATA, RESOURCE)

	 * 

	 * @param event - The EntryEvent that occurred

	 */

	@Override

	public void entryAdded(EntryEvent<Identifier, SystemMetadata> event) {

		// handle as update - that method will create if necessary

		entryUpdated(event);

	}

	/**

	 * Implement the EntryListener interface for Hazelcast, reponding to entry

	 * evicted events in the hzSystemMetadata map.  Evaluate the entry and create

	 * CNReplicationTasks as appropriate (for DATA, METADATA, RESOURCE)

	 * 

	 * @param event - The EntryEvent that occurred

	 */

	@Override

	public void entryEvicted(EntryEvent<Identifier, SystemMetadata> event) {

	  // nothing to do, entries are still in the backing store

	}

	/**

	 * Implement the EntryListener interface for Hazelcast, reponding to entry

	 * removed events in the hzSystemMetadata map.  Evaluate the entry and create

	 * CNReplicationTasks as appropriate (for DATA, METADATA, RESOURCE)

	 * 

	 * @param event - The EntryEvent that occurred

	 */

	@Override

	public void entryRemoved(EntryEvent<Identifier, SystemMetadata> event) {

	  // we don't remove objects

	}

	/**

	 * Implement the EntryListener interface for Hazelcast, reponding to entry

	 * updated events in the hzSystemMetadata map.  Evaluate the entry and create

	 * CNReplicationTasks as appropriate (for DATA, METADATA, RESOURCE)

	 * 

	 * @param event - The EntryEvent that occurred

	 */

	@Override

	public void entryUpdated(EntryEvent<Identifier, SystemMetadata> event) {

			logMetacat.debug("Entry added/updated to System Metadata map: " + event.getKey().getValue());

			PartitionService partitionService = Hazelcast.getPartitionService();

			Partition partition = partitionService.getPartition(event.getKey());

			Member ownerMember = partition.getOwner();

			if (!ownerMember.localMember()) {

				// need to pull the entry into the local store

				logMetacat.debug("Saving entry locally: " + event.getKey().getValue());

				try {

					if (!IdentifierManager.getInstance().systemMetadataExists(event.getKey().getValue())) {

						IdentifierManager.getInstance().createSystemMetadata(event.getValue());

					} else {

						IdentifierManager.getInstance().updateSystemMetadata(event.getValue());

					}

				} catch (McdbDocNotFoundException e) {

					logMetacat.error(

							"Could not save System Metadata to local store.", e);

				}

			}

			// TODO evaluate the type of system metadata change, decide if it

			// warrants a replication event, what type (DATA, METADATA, RESOURCE),

			// iteratively lock the PID, create and submit the tasks, and expect a

			// result back. Deal with exceptions.

			boolean isMetadata = D1NodeService.isScienceMetadata(event.getValue());

			// TODO: do we need to do anything explicit here?

	}

}