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.crosswalk;

import java.io.FileInputStream;

import java.io.StringReader;

import java.io.StringWriter;

import java.util.HashMap;

import java.util.Properties;

import javax.xml.transform.Transformer;

import javax.xml.transform.TransformerFactory;

import javax.xml.transform.stream.StreamResult;

import javax.xml.transform.stream.StreamSource;

import ORG.oclc.oai.server.crosswalk.Crosswalk;

import ORG.oclc.oai.server.verb.CannotDisseminateFormatException;

import ORG.oclc.oai.server.verb.OAIInternalServerError;

/**

 * Convert native "item" to oai_dc. In this case, the native "item" is assumed

 * to already be formatted as an OAI <record> element, with the possible

 * exception that multiple metadataFormats may be present in the <metadata>

 * element. The "crosswalk", merely involves pulling out the one that is

 * requested.

 */

public class Eml2oai_dc extends Crosswalk {

  /* Class fields */

  private static String dirPath = null;

  private static final String XSLT_NAME_200 = "eml200toDublinCore.xsl";

  private static final String XSLT_NAME_201 = "eml201toDublinCore.xsl";

  private static final String XSLT_NAME_210 = "eml210toDublinCore.xsl";

  private static final String SCHEMA_LOCATION =

    "http://www.openarchives.org/OAI/2.0/oai_dc/ " +

    "http://www.openarchives.org/OAI/2.0/oai_dc.xsd";

  /* Instance fields */

  private Transformer transformer = null;

  private Transformer transformer200 = null;

  private Transformer transformer201 = null;

  private Transformer transformer210 = null;

  /* Constructors */

  /**

   * The constructor assigns the schemaLocation associated with this crosswalk.

   * Since the crosswalk is trivial in this case, no properties are utilized.

   * 

   * @param properties

   *          properties that are needed to configure the crosswalk.

   */

  public Eml2oai_dc(Properties properties) throws OAIInternalServerError {

    super(SCHEMA_LOCATION);

    String xsltPath200 = dirPath + "/" + XSLT_NAME_200;

    String xsltPath201 = dirPath + "/" + XSLT_NAME_201;

    String xsltPath210 = dirPath + "/" + XSLT_NAME_210;

    try {

      TransformerFactory tFactory200 = TransformerFactory.newInstance();

      FileInputStream fileInputStream200 = new FileInputStream(xsltPath200);

      StreamSource xslSource200 = new StreamSource(fileInputStream200);

      this.transformer200 = tFactory200.newTransformer(xslSource200);

      TransformerFactory tFactory201 = TransformerFactory.newInstance();

      FileInputStream fileInputStream201 = new FileInputStream(xsltPath201);

      StreamSource xslSource201 = new StreamSource(fileInputStream201);

      this.transformer201 = tFactory201.newTransformer(xslSource201);

      TransformerFactory tFactory210 = TransformerFactory.newInstance();

      FileInputStream fileInputStream210 = new FileInputStream(xsltPath210);

      StreamSource xslSource210 = new StreamSource(fileInputStream210);

      this.transformer210 = tFactory210.newTransformer(xslSource210);

    } 

    catch (Exception e) {

      e.printStackTrace();

      throw new OAIInternalServerError(e.getMessage());

    }

  }

  /* Class methods */

  public static void setDirPath(String configDir) {

    Eml2oai_dc.dirPath = configDir;

  }

  /* Instance methods */

  /**

   * Perform the actual crosswalk.

   * 

   * @param nativeItem

   *          the native "item". In this case, it is already formatted as an OAI

   *          <record> element, with the possible exception that multiple

   *          metadataFormats are present in the <metadata> element.

   * @return a String containing the FileMap to be stored within the <metadata>

   *         element.

   * @exception CannotDisseminateFormatException

   *              nativeItem doesn't support this format.

   */

  public String createMetadata(Object nativeItem)

      throws CannotDisseminateFormatException {

    HashMap recordMap = (HashMap) nativeItem;

    try {

      //String xmlRec = (new String((byte[]) recordMap.get("recordBytes"),

      //    "UTF-8")).trim();

      String xmlRec = (String) recordMap.get("recordBytes");

      xmlRec = xmlRec.trim();

      if (xmlRec.startsWith("<?")) {

        int offset = xmlRec.indexOf("?>");

        xmlRec = xmlRec.substring(offset + 2);

      }

      if (xmlRec.contains("eml://ecoinformatics.org/eml-2.0.0")) {

        transformer = transformer200;

      }

      else if (xmlRec.contains("eml://ecoinformatics.org/eml-2.0.1")) {

        transformer = transformer201;

      }

      else if (xmlRec.contains("eml://ecoinformatics.org/eml-2.1.0")) {

        transformer = transformer210;

      }

      StringReader stringReader = new StringReader(xmlRec);

      StreamSource streamSource = new StreamSource(stringReader);

      StringWriter stringWriter = new StringWriter();

      synchronized (transformer) {

        transformer.transform(streamSource, new StreamResult(stringWriter));

      }

      return stringWriter.toString();

    } 

    catch (Exception e) {

      throw new CannotDisseminateFormatException(e.getMessage());

    }

  }

  /**

   * Can this nativeItem be represented in DC format?

   * 

   * @param nativeItem

   *          a record in native format

   * @return true if DC format is possible, false otherwise.

   */

  public boolean isAvailableFor(Object nativeItem) {

    return true;

  }

}