Metacat

package edu.ucsb.nceas.metacat.dataone.hazelcast;

import java.sql.SQLException;

import java.util.Collection;

import java.util.Collections;

import java.util.HashSet;

import java.util.Hashtable;

import java.util.List;

import java.util.Map;

import java.util.Set;

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

import com.hazelcast.core.MapLoader;

import edu.ucsb.nceas.metacat.DBUtil;

import edu.ucsb.nceas.metacat.IdentifierManager;

import edu.ucsb.nceas.metacat.McdbDocNotFoundException;

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

import edu.ucsb.nceas.utilities.FileUtil;

import edu.ucsb.nceas.utilities.PropertyNotFoundException;

/**

 * MapLoader implementation for a hazelcast ObjectPath.  This class is called

 * when the ObjectPathMap needs to refresh against the persistent data-store.

 * 

 * @author rnahf

 *

 */

public class ObjectPathMapLoader implements MapLoader<Identifier, String> {

	private static IdentifierManager im;

	private static DBUtil dbUtil;

	private static String dataPath;

	private static String metadataPath;

	/**

	 * creates an ObjectPathMapLoader

	 */

	public ObjectPathMapLoader() {

		try {

			dataPath = PropertyService.getProperty("application.datafilepath");

			metadataPath = PropertyService.getProperty("application.documentfilepath");

		} catch (PropertyNotFoundException e) {

			// TODO Auto-generated catch block

			e.printStackTrace();

		}

		im = IdentifierManager.getInstance();

		dbUtil = new DBUtil();

	}

	/*

	 * Metadata is stored in a different place on the filesystem than

	 * the data.  The doctype value for metadata can vary, but for data

	 * is always 'BIN', so using a simple if-then-else to separate

	 */

	private String pathToDocid(String docid) throws SQLException {

		String revType = dbUtil.getCurrentRevisionAndDocTypeForGivenDocument(docid);

		String[] rt = revType.split(";");

		String docType = rt[1];

		String revision = rt[0];

		if (docType.equals("BIN")) {

			return dataPath + FileUtil.getFS() + docid + "." + revision;

		} else {

			return metadataPath + FileUtil.getFS() + docid + "." + revision;

		}		

	}

	/**

	 *  Implementation of hazelcast MapLoader interface method.

	 *  for the provided Identifier (as key), looks up the localID

	 *  and revision

	 */

	@Override

	public String load(Identifier key) 

	{

		String docid = null;

		String path = null;

		try {

			docid = im.getLocalId(key.getValue());

			path = pathToDocid(docid);

		} catch (McdbDocNotFoundException e) {

			// TODO Auto-generated catch block

			e.printStackTrace();

			return null;

		} catch (SQLException e) {

			// TODO Auto-generated catch block

			e.printStackTrace();

		}

		return path;

	}

	/**

	 *  Implementation of hazelcast MapLoader interface method.

	 */

	@Override

	public Map<Identifier, String> loadAll(Collection<Identifier> identifiers) {

		Hashtable<Identifier,String> map = new Hashtable<Identifier,String>();

		for (Identifier id : identifiers) {

			try {

				String docid = im.getLocalId(id.getValue());

				map.put(id, pathToDocid(docid));

			} catch (McdbDocNotFoundException e) {

				// TODO Auto-generated catch block

				e.printStackTrace();

			} catch (SQLException e) {

				// TODO Auto-generated catch block

				e.printStackTrace();

			}

		}

		return map;

	}

	/**

	 * Hazelcast documents a few ways to implement this method, depending on specific

	 * usage.  Preloading all of the GUIDs may be an unnecessarily long operation,

	 * so this implementation returns NULL, and loading will be shifted to the other

	 * method calls.

	 */

	@Override

	public Set<Identifier> loadAllKeys() {

		return null;

		/*  ---- this would be another way to implement, using existing methods

		 *  ---- in IdentifierManager, and DBUtil.  but it is still problematic

		 *  ---- in how it goes from docid to GUID wrt revisions

		 *  ---- 

		 *  ---- better would be a new call to the identifier table listing all GUIDs

		 *  ---- (from new method in IdentifierManager)

		Set<Identifier> set = Collections.synchronizedSet(new HashSet<Identifier>());

		List<String> docids = null;

		try {

			docids = im.getAllLocalIds();

			for(String docid : docids) {

				Identifier id = new Identifier();

				// TODO: need new query for going from localID to guid.

				id.setValue(im.getGUID(docid, im.getLatestRevForLocalId(docid)));

				set.add(id);

			}

		} catch (Exception e) {

			// TODO Auto-generated catch block

			e.printStackTrace();

		}

		return set;

		*/

	}

}