ORG.oclc.oai.server.crosswalk.NodePassThruCrosswalk Maven / Gradle / Ivy

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/**
 * 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 ORG.oclc.oai.server.crosswalk;

import java.io.StringWriter;
import java.util.HashMap;

import javax.xml.transform.OutputKeys;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;

import org.w3c.dom.Element;

// import gov.loc.www.zing.srw.StringOrXmlFragment;
// import org.apache.axis.message.MessageElement;

/**
 * Convert native "item" to oai_dc. In this case, the native "item"
 * is assumed to already be formatted as an OAI  element,
 * with the possible exception that multiple metadataFormats may
 * be present in the  element. The "crosswalk", merely
 * involves pulling out the one that is requested.
 */
public class NodePassThruCrosswalk extends Crosswalk {
//     private static Logger logger = Logger.getLogger(NodePassThruCrosswalk.class);
    private static Transformer transformer = null;
    
    /**
     * 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 NodePassThruCrosswalk(CrosswalkItem crosswalkItem) {
	super(crosswalkItem.getMetadataNamespace() + " " + crosswalkItem.getSchema());
// 	BasicConfigurator.configure();
	TransformerFactory transformerFactory = TransformerFactory.newInstance();
	try {
	    transformer = transformerFactory.newTransformer();
	    transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes");
	    transformer.setOutputProperty(OutputKeys.STANDALONE, "no");
	    transformer.setOutputProperty(OutputKeys.INDENT, "yes");
	} catch (Exception e) {
	    e.printStackTrace();
// 	    logger.fatal("failed to create transformer", e);
	}
    }

    /**
     * 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;
    }

    /**
     * Perform the actual crosswalk.
     *
     * @param nativeItem the native "item". In this case, it is
     * already formatted as an OAI  element, with the
     * possible exception that multiple metadataFormats are
     * present in the  element.
     * @return a String containing the XML to be stored within the  element.
     */
    public String createMetadata(Object nativeItem) {
	try {
	    HashMap hashMap = (HashMap)nativeItem;
	    Element dataNode = (Element)hashMap.get("metadata");
	    DOMSource source = new DOMSource(dataNode);
	    StringWriter sw = new StringWriter();
	    StreamResult result = new StreamResult(sw);
	    synchronized (transformer) {
		transformer.transform(source, result);
	    }
	    return sw.toString();
	} catch (Exception e) {
// 	    logger.warn("NodePassThruCrosswalk.createMetadata failed", e);
	    e.printStackTrace();
	    return e.getMessage();
	}
// 	MessageElement[] messageElement = stringOrXmlFragment.get_any();
// 	StringBuffer sb = new StringBuffer();
// 	for (int i=0; i