Metacat

/**

 *  '$RCSfile$'

 *    Purpose: A Class that implements session utility methods 

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

 *             National Center for Ecological Analysis and Synthesis

 *    Authors: Christopher Jones

 * 

 *   '$Author: $'

 *     '$Date: $'

 * '$Revision: $'

 *

 * 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.service;

import org.apache.commons.io.IOUtils;

import org.apache.log4j.Logger;

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

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

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

/**

 *  The ObjectFormatService manages the list of object formats registered

 *  within Metacat.  This includes schema types, mime types, and other

 *  information related to a particular format.  The service provides

 *  functionality for the DataONE MemberNode and CoordinatingNode components,

 *  with CoordinatingNodes providing the authoritative list of object formats.

 */

public class ObjectFormatService extends BaseService {

  /* The instance of the logging class */

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

  /* The singleton instance of the object format service */

  private ObjectFormatService objectFormatService = null;

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

  private static final String OBJECT_FORMATS_SCOPE = "OBJECT_FORMAT_LIST.1";

  /* The revision of the object formats document */

  private int rev;

  /*

   * Constructor: Creates an instance of the object format service. Since

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

   */

  private ObjectFormatService() {

    super();

    this._serviceName="ObjectFormatService";

    try {

      doRefresh();

    } catch (ServiceException se) {

      logMetacat.debug("There was a problem creating the ObjectFormatService. " +

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

    }

  }

  /**

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

   *  or instantiate one if it has not been already.

   *

   * @return objectFormatService - The instance of the object format service

   */

  public ObjectFormatService getInstance(){

    if ( this.objectFormatService == null ) {

      this.objectFormatService = new ObjectFormatService();

    }

    return this.objectFormatService;

  }

  /**

   * Refreshes the object format service by manually updating the object

   * format document.

   */

  public void doRefresh() throws ServiceException {

    // stub only

    logMetacat.debug("ObjectFormatService.doRefresh() called. " +

                     "Refreshing the object format service.");

    return;

  }

  /**

   * Indicate whether or not this service is refreshable.  In this case it is,

   * where the ObjectFormatService can manually get the latest object format

   * document from Metacat.

   *

   * @return refreshable - the boolean refreshable status

   */

  public boolean refreshable() {

    return true;

  }

  /**

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

   * respond to requests. Not implemented yet.

   */

  public void stop() throws ServiceException {

    // stub only 

    return;

  }

}