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 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.metacat.shared.ServiceException;

import edu.ucsb.nceas.utilities.FileUtil;

import edu.ucsb.nceas.utilities.PropertyNotFoundException;

/**

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

 * when the IMap get methods needs to refresh against the persistent data-store.

 * The use case for this class is to communicate the filepath between JVMs on

 * the same machine, specifically between the metacat instance and the d1_indexer.

 * 

 * d1_indexer will get Identifiers from elsewhere, but use this class to get

 * the paths to their associated files.  The getAllKeys() method will

 * return null in a live setting, to avoid possibly expensive preloading

 * 

 * @author rnahf

 */

public class ObjectPathMap implements MapLoader<String, String> {

	private static IdentifierManager im;

	private static String dataPath;

	private static String metadataPath;

	/**

	 * creates an ObjectPathMap

	 */

	public ObjectPathMap() {

		try {

			PropertyService ps = PropertyService.getInstance();

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

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

		} catch (PropertyNotFoundException e) {

			// TODO Auto-generated catch block

			e.printStackTrace();

		} catch (ServiceException 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(String key) 

	{

		String docid = null;

		String path = null;

		try {

			docid = im.getLocalId(key);

			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<String, String> loadAll(Collection<String> identifiers) {

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

		for (String id : identifiers) {

			try {

				String docid = im.getLocalId(id);

				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 will

	 * do this to avoid pre-loading a very long list unnecessarily)

	 */

	@Override

	public Set<String> loadAllKeys() 

	{

		return null;

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

//

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

//		for (String guid : guids) {

//			set.add(guid);

//		}

//		return set;

	}

}