D-Net

package eu.dnetlib.data.transform;

import java.io.StringReader;

import java.util.Arrays;

import java.util.List;

import java.util.stream.Collectors;

import javax.xml.transform.Transformer;

import javax.xml.transform.stream.StreamSource;

import com.google.common.base.Function;

import com.ximpleware.AutoPilot;

import com.ximpleware.VTDGen;

import com.ximpleware.VTDNav;

import eu.dnetlib.data.graph.model.DNGFDecoder;

import eu.dnetlib.data.transform.VtdUtilityParser.Node;

import org.apache.commons.codec.binary.Base64;

import org.apache.commons.lang3.StringUtils;

import org.apache.commons.logging.Log;

import org.apache.commons.logging.LogFactory;

import org.dom4j.io.DocumentResult;

public class XsltRowTransformer implements Function<String, List<Row>> {

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

	public static final String DATA_XPATH = "/ROWS/ROW";

	public static final List<String> ATTRS = Arrays.asList("value", "mode");

	private Transformer transformer;

	public XsltRowTransformer(final Transformer transformer) {

		this.transformer = transformer;

		log.info(String.format("using trasformer: '%s'", getTransformerClassName()));

	}

	private List<Row> transform(final String xml) {

		final DocumentResult result = new DocumentResult();

		try {

			transformer.transform(new StreamSource(new StringReader(xml)), result);

			final VTDGen parser = new VTDGen();

			parser.setDoc(result.getDocument().asXML().getBytes());

			parser.parse(true);

			final VTDNav nav = parser.getNav();

			final AutoPilot autoPilot = new AutoPilot(nav);

			return VtdUtilityParser.getTextValuesWithAttributes(autoPilot, nav, DATA_XPATH, ATTRS)

					.stream()

					.map(this::asRow)

					.collect(Collectors.toList());

		} catch (Exception e) {

			log.error("Error parsing xml:\n" + xml, e);

			throw new RuntimeException("Unable to parse document:\n" + xml, e);

		}

	}

	private Row asRow(final Node base64Node) {

		final String base64 = base64Node.getAttributes().get("value");

		if (StringUtils.isBlank(base64))

			throw new IllegalArgumentException("empty protocolbuffer value, check xslt");

		final DNGFDecoder d = DNGFDecoder.decode(Base64.decodeBase64(base64));

		final String qualifier = getQualifier(base64Node, d);

		return new Row(d.getColumnFamily(), d.getRowkey(), Arrays.asList(new Column<>(qualifier, d.getDNGF().toByteArray())));

	}

	private String getQualifier(final Node base64Node, final DNGFDecoder d) {

		if("update".equals(base64Node.getAttributes().get("mode"))) {

			return "update_" + System.nanoTime();

		}

		return d.getQualifier();

	}

	public String getTransformerClassName() {

		return transformer != null ? transformer.getClass().getName() : "unknown";

	}

	@Override

	public List<Row> apply(final String xml) {

		return transform(xml);

	}

}