D-Net

package eu.dnetlib.enabling.tools;

import java.io.StringWriter;

import java.util.Date;

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.dom.DOMSource;

import javax.xml.transform.stream.StreamResult;

import javax.xml.xpath.XPath;

import javax.xml.xpath.XPathConstants;

import javax.xml.xpath.XPathExpressionException;

import javax.xml.xpath.XPathFactory;

import org.apache.commons.logging.Log;

import org.apache.commons.logging.LogFactory;

import org.w3c.dom.Document;

import org.w3c.dom.Element;

import eu.dnetlib.miscutils.datetime.DateUtils;

/**

 * OpaqueResource holding a plain old DOM document.

 *

 * @author marko

 *

 */

public class DOMOpaqueResource implements OpaqueResource {

	/**

	 * xpath expression error message.

	 */

	private static final String XPATH_ERROR = "cannot compile xpath expression";

	/**

	 * value attribute.

	 */

	private static final String VALUE_ATTR = "value";

	/**

	 * logger.

	 */

	private static final Log log = LogFactory.getLog(DOMOpaqueResource.class); // NOPMD by marko on 11/24/08 5:02 PM

	/**

	 * resource identifier.

	 */

	private String resourceId;

	/**

	 * resource type.

	 */

	private String resourceType;

	/**

	 * resource kind.

	 */

	private String resourceKind;

	/**

	 * resource uri.

	 */

	private String resourceUri;

	/**

	 * modification time stamp.

	 */

	private Date modificationDate;

	/**

	 * original document DOM.

	 */

	private Document dom;

	/**

	 * xslt transformer instance.

	 */

	private Transformer transformer;

	/**

	 * construct a DOMOpaqueInstance from a W3C DOM document.

	 *

	 * @param dom

	 *            DOM document

	 * @throws XPathExpressionException

	 *             happens

	 */

	public DOMOpaqueResource(final Document dom) throws XPathExpressionException {

		this.dom = dom;

		try {

			this.transformer = TransformerFactory.newInstance().newTransformer();

		} catch (final TransformerConfigurationException e) {

			throw new IllegalStateException("transformer configuration", e);

		} catch (final TransformerFactoryConfigurationError e) {

			throw new IllegalStateException("transformer configuration", e);

		}

		final XPath xpath = XPathFactory.newInstance().newXPath();

		this.resourceId = xpath.evaluate("/RESOURCE_PROFILE/HEADER/RESOURCE_IDENTIFIER/@value", dom);

		this.resourceType = xpath.evaluate("/RESOURCE_PROFILE/HEADER/RESOURCE_TYPE/@value", dom);

		this.resourceKind = xpath.evaluate("/RESOURCE_PROFILE/HEADER/RESOURCE_KIND/@value", dom);

		this.resourceUri = xpath.evaluate("/RESOURCE_PROFILE/HEADER/RESOURCE_URI/@value", dom);

		final String modificationDateSource = xpath.evaluate("/RESOURCE_PROFILE/HEADER/DATE_OF_CREATION/@value", dom);

		try {

			this.modificationDate = new DateUtils().parse(modificationDateSource);

		} catch (final IllegalStateException e) {

			log.debug("invalid date '" + modificationDateSource + "'", e);

		}

	}

	/**

	 * {@inheritDoc}

	 *

	 * @see eu.dnetlib.enabling.tools.OpaqueResource#asDom()

	 */

	@Override

	public Document asDom() {

		return getDom();

	}

	/**

	 * {@inheritDoc}

	 *

	 * @see eu.dnetlib.enabling.tools.OpaqueResource#asString()

	 */

	@Override

	public String asString() {

		final StringWriter writer = new StringWriter();

		try {

			this.transformer.transform(new DOMSource(getDom()), new StreamResult(writer));

		} catch (final TransformerException e) {

			log.fatal("cannot serialize document", e);

			return null;

		}

		return writer.toString();

	}

	public Document getDom() {

		return this.dom;

	}

	public void setDom(final Document dom) {

		this.dom = dom;

	}

	@Override

	public String getResourceId() {

		return this.resourceId;

	}

	/**

	 * {@inheritDoc}

	 *

	 * @see eu.dnetlib.enabling.tools.OpaqueResource#setResourceId(java.lang.String)

	 */

	@Override

	public void setResourceId(final String identifier) {

		try {

			final XPath xpath = XPathFactory.newInstance().newXPath();

			final Element idEl = (Element) xpath.evaluate("/RESOURCE_PROFILE/HEADER/RESOURCE_IDENTIFIER", asDom(), XPathConstants.NODE);

			idEl.setAttribute(VALUE_ATTR, identifier);

			this.resourceId = identifier;

		} catch (final XPathExpressionException e) {

			throw new IllegalStateException(XPATH_ERROR, e);

		}

	}

	@Override

	public String getResourceType() {

		return this.resourceType;

	}

	public void setResourceType(final String resourceType) {

		this.resourceType = resourceType;

	}

	@Override

	public String getResourceKind() {

		return this.resourceKind;

	}

	/**

	 * {@inheritDoc}

	 *

	 * @see eu.dnetlib.enabling.tools.OpaqueResource#setResourceKind(java.lang.String)

	 */

	@Override

	public void setResourceKind(final String resourceKind) {

		try {

			final XPath xpath = XPathFactory.newInstance().newXPath();

			final Element kindEl = (Element) xpath.evaluate("/RESOURCE_PROFILE/HEADER/RESOURCE_KIND", asDom(), XPathConstants.NODE);

			kindEl.setAttribute(VALUE_ATTR, resourceKind);

			this.resourceKind = resourceKind;

		} catch (final XPathExpressionException e) {

			throw new IllegalStateException(XPATH_ERROR, e);

		}

	}

	@Override

	public Date getModificationDate() {

		return this.modificationDate;

	}

	/**

	 * {@inheritDoc}

	 *

	 * @see eu.dnetlib.enabling.tools.OpaqueResource#setModificationDate(java.util.Date)

	 */

	@Override

	public void setModificationDate(final Date modificationDate) {

		try {

			final XPath xpath = XPathFactory.newInstance().newXPath();

			final Element idEl = (Element) xpath.evaluate("/RESOURCE_PROFILE/HEADER/DATE_OF_CREATION", asDom(), XPathConstants.NODE);

			if (idEl == null) {

				log.warn("resource with type " + getResourceType() + " has no date of creation element");

				return;

			}

			idEl.setAttribute(VALUE_ATTR, new DateUtils(modificationDate).getDateAsISO8601String());

			this.modificationDate = modificationDate;

		} catch (final XPathExpressionException e) {

			throw new IllegalStateException(XPATH_ERROR, e);

		}

	}

	@Override

	public String getResourceUri() {

		return this.resourceUri;

	}

	/**

	 * {@inheritDoc}

	 *

	 * @see eu.dnetlib.enabling.tools.OpaqueResource#setResourceUri(java.lang.String)

	 */

	@Override

	public void setResourceUri(final String resourceUri) {

		try {

			final XPath xpath = XPathFactory.newInstance().newXPath();

			final Element uriEl = (Element) xpath.evaluate("/RESOURCE_PROFILE/HEADER/RESOURCE_URI", asDom(), XPathConstants.NODE);

			uriEl.setAttribute(VALUE_ATTR, resourceUri);

			this.resourceUri = resourceUri;

		} catch (final XPathExpressionException e) {

			throw new IllegalStateException(XPATH_ERROR, e);

		}

	}

	public Transformer getTransformer() {

		return this.transformer;

	}

	public void setTransformer(final Transformer transformer) {

		this.transformer = transformer;

	}

}