D-Net

package eu.dnetlib.validator.service.impls.providers;

import java.io.IOException;

import java.io.StringReader;

import java.net.MalformedURLException;

import java.net.URL;

import javax.xml.parsers.DocumentBuilder;

import javax.xml.parsers.DocumentBuilderFactory;

import javax.xml.parsers.ParserConfigurationException;

import org.w3c.dom.Document;

import org.xml.sax.InputSource;

import org.xml.sax.SAXException;

import eu.dnetlib.validator.engine.data.DataException;

import eu.dnetlib.validator.engine.data.Provider;

import eu.dnetlib.validator.engine.data.ResultSet;

import eu.dnetlib.validator.engine.execution.ValidationObject;

import eu.dnetlib.validator.service.impls.valobjs.XMLTextValidationObject;

/**

 * A provider that retrieves the XML response created by sending a verb request to an OAI-PMH repository.

 * 

 * @author Manos Karvounis

 * 

 */

public class OAIPMHSinglePageVerbProvider extends Provider {

	private static final long serialVersionUID = -8398496197308270467L;

	private int timeout;

	private int delay;

	private int retryDelay;

	private int retryEfforts;

	public static final String BASEURL = "BASEURL";

	/**

	 * The verb request to be issued.

	 * Note that you should not include the "?verb=" part, but if you need additional parameters, you should include them as part of the verb.

	 * E.g., "GetRecord&metadataPrefix=oai_dc&identifier=..."

	 */

	public static final String VERB="VERB";

	/**

	 * The maximum time to wait for a response from the repository (in millis)

	 */

//	public static final String TIMEOUT = "TIMEOUT";

	/**

	 * How much time to wait between consecutive HTTP requests to the repository

	 * (in millis).

	 */

//	public static final String DELAY = "DELAY";

	/**

	 * How much to wait if an HTTP request fails before trying again by

	 * resending the request.

	 */

//	public static final String RETRY_DELAY = "RETRY_DELAY";

	/**

	 * If an HTTP requests fails, how many times to try to resend the request.

	 */

//	public static final String RETRY_EFFORTS = "RETRY_EFFORTS";

	public OAIPMHSinglePageVerbProvider() {

		super(2);

	}

	@Override

	public ResultSet<ValidationObject> getValidationObjects() throws ProviderException {

		return new OAIPMHVerbResultSet();

	}

	@Override

	public ResultSet<String> getValidationObjectIds() throws ProviderException {

		throw new UnsupportedOperationException();

	}

	@Override

	public ValidationObject getValidationObject(String valObjId) throws ProviderException {

		throw new UnsupportedOperationException();

	}

	private class OAIPMHVerbResultSet implements ResultSet<ValidationObject> {

		protected DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();

		protected DocumentBuilder builder;

		private URLStreamer streamer = new URLStreamer();

		private Document doc = null;

		boolean finished = false;

		public OAIPMHVerbResultSet() {

			super();

			try {

				builder = factory.newDocumentBuilder();

			} catch (ParserConfigurationException e) {

				log.error("", e);

			}

		}

		@Override

		public boolean next() throws DataException {

			if(!finished) {

				String surl = pros.getProperty(BASEURL) + "?verb="+pros.getProperty(VERB);

				String response = null;

				log.debug("Issuing request: "+surl);

				try {

					response = streamer.getResponse(new URL(surl), timeout, delay, retryDelay, retryEfforts);

				} catch (NumberFormatException e) {

					log.error("", e);

					throw new DataException();

				} catch (MalformedURLException e) {

					log.error("", e);

					throw new DataException();

				} catch (IOException e) {

					log.error("", e);

					throw new DataException();

				}

				InputSource is = new InputSource(new StringReader(response));

				try {

					doc = builder.parse(is);

				} catch (SAXException e) {

					log.error("", e);

					throw new DataException();

				} catch (IOException e) {

					log.error("", e);

					throw new DataException();

				}

				finished = true;

				return true;

			}

			return false;

		}

		@Override

		public ValidationObject get() throws DataException {

			XMLTextValidationObject obj = new XMLTextValidationObject(doc);

			obj.setId(pros.getProperty(VERB)+"@"+pros.getProperty(BASEURL));

			log.debug("Getting object with id "+obj.getId());

			return obj;

		}

		@Override

		public String getError() {

			// TODO Auto-generated method stub

			return null;

		}

	}

	@Override

	public ResultSet<ValidationObject> getValidationObjects(String entity)

			throws ProviderException {

		// TODO Auto-generated method stub

		return null;

	}

	public Integer getTimeout() {

		return timeout;

	}

	public void setTimeout(Integer timeout) {

		this.timeout = timeout;

	}

	public Integer getDelay() {

		return delay;

	}

	public void setDelay(Integer delay) {

		this.delay = delay;

	}

	public Integer getRetryDelay() {

		return retryDelay;

	}

	public void setRetryDelay(Integer retryDelay) {

		this.retryDelay = retryDelay;

	}

	public Integer getRetryEfforts() {

		return retryEfforts;

	}

	public void setRetryEfforts(Integer retryEfforts) {

		this.retryEfforts = retryEfforts;

	}

}