ModsXmlHelper.java

/**
 * Copyright 2008 The University of North Carolina at Chapel Hill
 *
 * 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.unc.lib.dl.xml;

import javax.xml.transform.Source;
import javax.xml.transform.Templates;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.TransformerFactoryConfigurationError;
import javax.xml.transform.URIResolver;
import javax.xml.transform.stream.StreamSource;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.jdom2.Document;
import org.jdom2.Element;
import org.jdom2.transform.JDOMResult;
import org.jdom2.transform.JDOMSource;

public class ModsXmlHelper {
	private static final String _stylesheetPackage = "/edu/unc/lib/dl/schematron/";
	private static final Log log = LogFactory.getLog(ModsXmlHelper.class);

	private static Templates mods2dc = null;
	private static Templates dcterms2MODS = null;

	private static Source mods2dcsrc = new StreamSource(ModsXmlHelper.class.getResourceAsStream(_stylesheetPackage
			+ "MODS3-22simpleDC.xsl"));
	
	private static Source dcterms2MODSSrc = new StreamSource(ModsXmlHelper.class.getResourceAsStream(_stylesheetPackage
			+ "dc2MODS/dcterms2MODS.xsl"));

	static {
		try {
			TransformerFactory factory = TransformerFactory.newInstance();
			// set a Resolver that can look in the classpath
			factory.setURIResolver(new URIResolver() {
				public Source resolve(String href, String base) throws TransformerException {
					Source result = null;
					result = new StreamSource(ModsXmlHelper.class.getResourceAsStream(_stylesheetPackage + href));
					return result;
				}
			});

			mods2dc = factory.newTemplates(mods2dcsrc);
			dcterms2MODS = factory.newTemplates(dcterms2MODSSrc);
		} catch (TransformerFactoryConfigurationError e) {
			log.error("Error setting up transformer factory.", e);
			throw new Error("Error setting up transformer factory", e);
		} catch (TransformerConfigurationException e) {
			log.error("Error setting up transformer.", e);
			throw new Error("Error setting up transformer", e);
		}
	}

	public static String getFormattedLabelText(Element mods) {
		String result = null;
		try {
			Document dc = transform(mods);
			result = dc.getRootElement().getChildText("title", JDOMNamespaceUtil.DC_NS);
		} catch (TransformerException e) {
			log.error("Cannot get label from MODS due to DC transform failure.", e);
		} catch (IllegalStateException e) {
			log.error("Cannot get label from MODS due to DC transform failure.", e);
		}
		return result;
	}

	public static Document transform(Element mods) throws TransformerException {
		Source modsSrc = new JDOMSource(mods);
		JDOMResult dcResult = new JDOMResult();
		Transformer t = null;
		try {
			t = mods2dc.newTransformer();
		} catch (TransformerConfigurationException e) {
			throw new Error("There was a problem configuring the transformer.", e);
		}
		t.transform(modsSrc, dcResult);
		return dcResult.getDocument();
	}
	
	public static Document transformDCTerms2MODS(Element dcterms) throws TransformerException {
		Source dctermsSrc = new JDOMSource(dcterms);
		JDOMResult modsResult = new JDOMResult();
		Transformer t = null;
		try {
			t = dcterms2MODS.newTransformer();
		} catch (TransformerConfigurationException e) {
			throw new Error("There was a problem configuring the transformer.", e);
		}
		t.transform(dctermsSrc, modsResult);
		return modsResult.getDocument();
	}
}