Metacat

/**

 * Copyright 2006 OCLC Online Computer Library Center Licensed under the Apache

 * License, Version 2.0 (the "License"); you may not use this file except in

 * compliance with the License. You may obtain a copy of the License at

 * http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or

 * agreed to in writing, software distributed under the License is distributed on

 * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express

 * or implied. See the License for the specific language governing permissions and

 * limitations under the License.

 */

package edu.ucsb.nceas.metacat.oaipmh.provider.server.catalog;

import java.util.HashMap;

import java.util.Iterator;

import java.util.Properties;

import java.util.StringTokenizer;

import edu.ucsb.nceas.metacat.oaipmh.provider.server.OAIHandler;

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

import edu.ucsb.nceas.utilities.PropertyNotFoundException;

import org.apache.log4j.Logger;

import ORG.oclc.oai.server.catalog.RecordFactory;

/**

 * MetacatRecordFactory converts native XML "items" to "record" Strings. This

 * factory assumes the native XML item looks exactly like the <record> element

 * of an OAI GetRecord response, with the possible exception that the <metadata>

 * element contains multiple metadataFormats from which to choose.

 */

public class MetacatRecordFactory extends RecordFactory {

  private static final Logger logger = 

                                   Logger.getLogger(MetacatRecordFactory.class);

  private String repositoryIdentifier = null;

  private String context = null;

  private final String TEST_CONTEXT = "knb";

  /**

   * Construct a MetacatRecordFactory capable of producing the Crosswalk(s)

   * specified in the properties file.

   * 

   * @param properties

   *          Contains information to configure the factory: specifically, the

   *          names of the crosswalk(s) supported

   * @exception IllegalArgumentException

   *              Something is wrong with the argument.

   */

  public MetacatRecordFactory(Properties properties)

      throws IllegalArgumentException {

    super(properties);

    if (OAIHandler.isIntegratedWithMetacat()) {

      try {

        context = PropertyService.getProperty("application.context");

      }

      catch (PropertyNotFoundException e) {

        logger.error("PropertyNotFoundException: " + 

                     "unable to determine application.context value");

      }

    }

    else {

      context = TEST_CONTEXT;

    }

    repositoryIdentifier=properties.getProperty("oaipmh.repositoryIdentifier");

    if (repositoryIdentifier == null) {

      String errorStr = 

              "oaipmh.repositoryIdentifier is missing from the properties file";

      throw new IllegalArgumentException(errorStr);

    }

  }

  /**

   * Utility method to parse the 'local identifier' from the OAI identifier

   * 

   * @param identifier

   *          OAI identifier (e.g.

   *          "http://metacat.lternet.edu/knb/metacat/knb-lter-gce.247")

   * 

   * @return local identifier (e.g. "knb-lter-gce.247")

   */

  public String fromOAIIdentifier(String identifier) {

    try {

      if (identifier != null) {

        int i = identifier.indexOf("/metacat/");

        String tailString = identifier.substring(i + 9);

        StringTokenizer tokenizer = new StringTokenizer(tailString, "/");

        String localIdentifier = tokenizer.nextToken();

        return localIdentifier;

      } else {

        return null;

      }

    } catch (Exception e) {

      return null;

    }

  }

  /**

   * Construct an OAI identifier from the native item

   * 

   * @param nativeItem

   *          native Item object

   * @return OAI identifier

   */

  public String getOAIIdentifier(Object nativeItem) {

    String localIdentifier = getLocalIdentifier(nativeItem);

    StringBuffer sb = new StringBuffer();

    sb.append("http://");

    sb.append(repositoryIdentifier);

    sb.append("/" + context + "/metacat/");

    sb.append(localIdentifier);

    return sb.toString();

  }

  /**

   * Extract the local identifier from the native item

   * 

   * @param nativeItem

   *          native Item object

   * @return local identifier

   */

  public String getLocalIdentifier(Object nativeItem) {

    HashMap nativeItemMap = (HashMap) nativeItem;

    String localIdentifier = (String) nativeItemMap.get("localIdentifier");

    return localIdentifier;

  }

  /**

   * get the datestamp from the item

   * 

   * @param nativeItem

   *          a native item presumably containing a datestamp somewhere

   * @return a String containing the datestamp for the item

   * @exception IllegalArgumentException

   *              Something is wrong with the argument.

   */

  public String getDatestamp(Object nativeItem) 

      throws IllegalArgumentException {

    return (String) ((HashMap) nativeItem).get("lastModified");

  }

  /**

   * get the setspec from the item

   * 

   * @param nativeItem

   *          a native item presumably containing a setspec somewhere

   * @return a String containing the setspec for the item

   * @exception IllegalArgumentException

   *              Something is wrong with the argument.

   */

  public Iterator getSetSpecs(Object nativeItem)

      throws IllegalArgumentException {

    return null;

  }

  /**

   * Get the about elements from the item

   * 

   * @param nativeItem

   *          a native item presumably containing about information somewhere

   * @return a Iterator of Strings containing <about>s for the item

   * @exception IllegalArgumentException

   *              Something is wrong with the argument.

   */

  public Iterator getAbouts(Object nativeItem) throws IllegalArgumentException {

    return null;

  }

  /**

   * Is the record deleted?

   * 

   * @param nativeItem

   *          a native item presumably containing a possible delete indicator

   * @return true if record is deleted, false if not

   * @exception IllegalArgumentException

   *              Something is wrong with the argument.

   */

  public boolean isDeleted(Object nativeItem) throws IllegalArgumentException {

    return false;

  }

  /**

   * Allows classes that implement RecordFactory to override the default

   * create() method. This is useful, for example, if the entire <record>

   * is already packaged as the native record. Return null if you want the

   * default handler to create it by calling the methods above individually.

   * 

   * @param nativeItem

   *          the native record

   * @param schemaURL

   *          the schemaURL desired for the response

   * @param the

   *          metadataPrefix from the request

   * @return a String containing the OAI <record> or null if the default

   *         method should be used.

   */

  public String quickCreate(Object nativeItem, String schemaLocation,

      String metadataPrefix) {

    // Don't perform quick creates

    return null;

  }

  /**

   * Convert a native "item" to a "record" String. Use this version of

   * createHeader if the setSpecs are derived from the nativeItem itself.

   * 

   * @param nativeItem

   *          the native record.

   * @return String[0] = "header" XML string String[1] = oai-identifier.

   * @exception IllegalArgumentException

   *              One of the header components for this record is bad.

   */

  public String[] createHeader(Object nativeItem)

      throws IllegalArgumentException {

    String oaiIdentifier = getOAIIdentifier(nativeItem);

    String datestamp = getDatestamp(nativeItem);

    Iterator setSpecs = getSetSpecs(nativeItem);

    boolean isDeleted = isDeleted(nativeItem);

    String[] headerArray = 

                    createHeader(oaiIdentifier, datestamp, setSpecs, isDeleted);

    return headerArray;

  }

}