Metacat

/**

 *  '$RCSfile$'

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

 *              National Center for Ecological Analysis and Synthesis

 *

 *   '$Author$'

 *     '$Date$'

 *

 * 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;

import java.io.ByteArrayInputStream;

import java.io.IOException;

import java.sql.SQLException;

import java.util.HashMap;

import org.apache.log4j.Logger;

import org.dataone.cn.batch.utils.TypeMarshaller;

import org.dataone.service.exceptions.InsufficientResources;

import org.dataone.service.exceptions.InvalidRequest;

import org.dataone.service.exceptions.NotFound;

import org.dataone.service.exceptions.NotImplemented;

import org.dataone.service.exceptions.ServiceFailure;

import org.dataone.service.types.ObjectFormat;

import org.dataone.service.types.ObjectFormatIdentifier;

import org.dataone.service.types.ObjectFormatList;

import org.jibx.runtime.JiBXException;

import edu.ucsb.nceas.metacat.DBUtil;

import edu.ucsb.nceas.metacat.DocumentImpl;

import edu.ucsb.nceas.metacat.McdbException;

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

import edu.ucsb.nceas.utilities.PropertyNotFoundException;

/**

 *

 * Implements a subset of the DataONE CNCore services in Metacat.

 *

 * @author jones, leinfelder

 */

public class ObjectFormatService {

	private Logger logMetacat = Logger.getLogger(ObjectFormatService.class);

	/* The scope of the object formats docid used as the metacat identifier */

	private final String OBJECT_FORMAT_DOCID = "OBJECT_FORMAT_LIST.1";

	/* The revision of the object formats document */

	private int rev;

	/* The separator of the object formats document */

	private String separator = ".";

	/* The accession number of the object formats document */

	private String accNumber = null;

	/* The list of object formats */

	private ObjectFormatList objectFormatList = null;

	/* the searchable map of object formats */

	private static HashMap<String, ObjectFormat> objectFormatMap;

	private static ObjectFormatService instance = null;

	public static ObjectFormatService getInstance() {

		if (instance == null) {

			instance = new ObjectFormatService();

		}

		return instance;

	}

	/**

	 * Constructor, private for singleton access

	 */

	private ObjectFormatService() {

	}

	/**

	 * Return the object format based on the given object format identifier

	 *

	 * @param fmtid

	 *            - the object format identifier to look up

	 * @return objectFormat - the desired object format

	 */

	public ObjectFormat getFormat(ObjectFormatIdentifier fmtid)

			throws InvalidRequest, ServiceFailure, NotFound,

			InsufficientResources, NotImplemented {

		logMetacat.debug("CNCoreImpl.getFormat() called.");

		ObjectFormat objectFormat = null;

		// look up the format in the object format map

		objectFormat = getObjectFormatMap().get(fmtid.getValue());

		// refresh the object format list if the format is null

		if (objectFormat == null) {

			getCachedList();

			objectFormat = getObjectFormatMap().get(fmtid.getValue());

			// the object format isn't registered

			if (objectFormat == null) {

				throw new NotFound("4848", "The format specified by "

						+ fmtid.getValue() + " does not exist at this node.");

			}

		}

		return objectFormat;

	}

	/**

	 * Return the list of object formats registered from the Coordinating Node.

	 *

	 * @return objectFormatList - the list of object formats

	 */

	public ObjectFormatList listFormats() throws InvalidRequest,

			ServiceFailure, NotFound, InsufficientResources, NotImplemented {

		try {

			objectFormatList = getCachedList();

		} catch (ServiceFailure sfe) {

			throw sfe;

		} catch (NotFound nfe) {

			throw nfe;

		}

		return objectFormatList;

	}

	/*

	 * Return the hash containing the fmtid and format mapping

	 *

	 * @return objectFormatMap - the hash of fmtid/format pairs

	 */

	private HashMap<String, ObjectFormat> getObjectFormatMap() {

		if (objectFormatMap == null) {

			objectFormatMap = new HashMap<String, ObjectFormat>();

		}

		return objectFormatMap;

	}

	/**

	 * Get the object format list cached in Metacat

	 */

	private ObjectFormatList getCachedList() throws NotFound, ServiceFailure {

		ObjectFormatList objectFormatList = null;

		try {

			// reset the accession number separator in case it is

			// different than the default

			try {

				separator = PropertyService

						.getProperty("document.accNumSeparator");

			} catch (PropertyNotFoundException pnfe) {

				// use the default separator, but log the issue

				logMetacat.debug("There was a problem finding the document "

						+ "separator property. The error message was: "

						+ pnfe.getMessage());

			}

			// get the latest accession number if it is in Metacat

			this.rev = DBUtil

					.getLatestRevisionInDocumentTable(this.OBJECT_FORMAT_DOCID);

			if (this.rev != -1) {

				this.accNumber = this.OBJECT_FORMAT_DOCID + this.separator

						+ this.rev;

				DocumentImpl objectFormatsDocument = new DocumentImpl(

						accNumber, false);

				ByteArrayInputStream bais = new ByteArrayInputStream(

						objectFormatsDocument.toString().getBytes());

				// deserialize the object format list

				try {

					objectFormatList = TypeMarshaller.unmarshalTypeFromStream(

							ObjectFormatList.class, bais);

				} catch (IOException e) {

					throw new ServiceFailure("4841",

							"Unexpected exception from the service - "

									+ e.getClass() + ": " + e.getMessage());

				} catch (InstantiationException e) {

					throw new ServiceFailure("4841",

							"Unexpected exception from the service - "

									+ e.getClass() + ": " + e.getMessage());

				} catch (IllegalAccessException e) {

					throw new ServiceFailure("4841",

							"Unexpected exception from the service - "

									+ e.getClass() + ": " + e.getMessage());

				} catch (JiBXException e) {

					throw new ServiceFailure("4841",

							"Unexpected exception from the service - "

									+ e.getClass() + ": " + e.getMessage());

				}

			} else {

				throw new NotFound("4843",

						"The object formats collection could not "

								+ "be found at this node.");

			}

		} catch (SQLException sqle) {

			throw new ServiceFailure("4841",

					"Unexpected exception from the service - "

							+ sqle.getClass() + ": " + sqle.getMessage());

		} catch (McdbException mcdbe) {

			throw new ServiceFailure("4841",

					"Unexpected exception from the service - "

							+ mcdbe.getClass() + ": " + mcdbe.getMessage());

		}

		// index the object format list based on the format identifier string

		int listSize = objectFormatList.sizeObjectFormats();

		for (int i = 0; i < listSize; i++) {

			ObjectFormat objectFormat = objectFormatList.getObjectFormat(i);

			String identifier = objectFormat.getFmtid().getValue();

			getObjectFormatMap().put(identifier, objectFormat);

		}

		return objectFormatList;

	}

}