Metacat

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

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.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 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();

	}

	/*

	 * 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 localid) throws McdbDocNotFoundException  {

		Hashtable<String, Object> ht = im.getDocumentInfo(localid);

		if (ht.get("doctype").equals("BIN")) {

			return dataPath + FileUtil.getFS() + localid;

		} else {

			return metadataPath + FileUtil.getFS() + localid;

		}		

	}

	/**

	 *  Implementation of hazelcast MapLoader interface method.

	 *  For the provided Identifier (as key), returns the path to the

	 *  document on the local filesystem.  Returns null if it can't 

	 *  create the path. 

	 */

	@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;

		}

		return path;

	}

	/**

	 *  Implementation of hazelcast MapLoader interface method.  This method loads

	 *  mappings for all Identifiers in the parameters.  Any Identifier not found

	 *  is not included in the resulting map.

	 */

	@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 should the map load an empty path instead of

				// leaving out the entire entry?

				e.printStackTrace();

			}

		}

		return map;

	}

	/**

	 * Return the full set of guids in the local metacat repository as

	 * dataone Identifiers.

	 * 

	 * (Hazelcast allows avoiding pre-loading by returning NULL, so consider

	 * re-implementing if that serves the purpose of this class better)

	 */

	@Override

	public Set<Identifier> loadAllKeys() {

		List<String> guids = im.getAllGUIDs();

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

		for (String guid : guids) {

			Identifier id = new Identifier();

			id.setValue(guid);

			set.add(id);

		}

		return set;

	}

}