D-Net

package eu.dnetlib.msro.workflows.nodes.download;

import java.io.ByteArrayInputStream;

import java.util.ArrayList;

import java.util.List;

import javax.xml.parsers.DocumentBuilder;

import javax.xml.parsers.DocumentBuilderFactory;

import javax.xml.xpath.XPath;

import javax.xml.xpath.XPathConstants;

import javax.xml.xpath.XPathExpression;

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.NodeList;

import com.google.common.base.Function;

import com.google.gson.Gson;

import eu.dnetlib.data.download.rmi.DownloadItem;

/**

 * The Class UrlExtractor.

 */

public class UrlExtractor implements Function<String, String> {

	private static final Log log = LogFactory.getLog(UrlExtractor.class);

	/** The xpath. */

	private String xpath;

	/** The xpath. */

	private String xpathMetadataID;

	public UrlExtractor(final String xpath, final String xpathMetadataID) {

		this.xpath = xpath;

		this.xpathMetadataID = xpathMetadataID;

	}

	/*

	 * (non-Javadoc)

	 * 

	 * @see com.google.common.base.Function#apply(java.lang.Object)

	 */

	@Override

	public String apply(final String input) {

		try {

			DownloadItem di = new DownloadItem();

			DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();

			DocumentBuilder builder;

			builder = factory.newDocumentBuilder();

			Document doc = builder.parse(new ByteArrayInputStream(input.getBytes()));

			XPathFactory xPathFactory = XPathFactory.newInstance();

			XPath myXpath = xPathFactory.newXPath();

			XPathExpression expression = myXpath.compile(xpath);

			Object values = expression.evaluate(doc, XPathConstants.NODESET);

			di.setUrl(getNodes((NodeList) values));

			di.setOriginalUrl(getNodes((NodeList) values));

			expression = myXpath.compile(xpathMetadataID);

			String extracted_metadataId = expression.evaluate(doc);

			di.setIdItemMetadata(extracted_metadataId);

			// di.setFileName(extracted_metadataId);

			return di.toJSON();

		} catch (Exception e) {

			log.error("OPSSS... Something bad happen on evaluating ", e);

			return null;

		}

	}

	private String getNodes(final NodeList nodes) {

		List<String> extracted_Url = new ArrayList<String>();

		if (nodes != null) {

			for (int i = 0; i < nodes.getLength(); i++) {

				extracted_Url.add(nodes.item(i).getNodeValue());

			}

		}

		return new Gson().toJson(extracted_Url);

	}

	/**

	 * Gets the xpath.

	 * 

	 * @return the xpath

	 */

	public String getXpath() {

		return xpath;

	}

	/**

	 * Sets the xpath.

	 * 

	 * @param xpath

	 *            the xpath to set

	 */

	public void setXpath(final String xpath) {

		this.xpath = xpath;

	}

	/**

	 * @return the xpathMetadataID

	 */

	public String getXpathMetadataID() {

		return xpathMetadataID;

	}

	/**

	 * @param xpathMetadataID

	 *            the xpathMetadataID to set

	 */

	public void setXpathMetadataID(final String xpathMetadataID) {

		this.xpathMetadataID = xpathMetadataID;

	}

}