D-Net

package eu.dnetlib.data.collector.plugins.datasources;

import java.io.InputStream;

import java.util.Iterator;

import java.util.NoSuchElementException;

import javax.xml.stream.XMLInputFactory;

import javax.xml.stream.XMLStreamConstants;

import javax.xml.stream.XMLStreamException;

import javax.xml.stream.XMLStreamReader;

import eu.dnetlib.data.collector.plugins.HttpConnector;

import eu.dnetlib.data.collector.rmi.CollectorServiceException;

import eu.dnetlib.data.collector.rmi.CollectorServiceRuntimeException;

import org.apache.commons.logging.Log;

import org.apache.commons.logging.LogFactory;

public class Re3DataRepositoriesIterator implements Iterator<String>, Iterable<String> {

	private static final Log log = LogFactory.getLog(Re3DataRepositoriesIterator.class); // NOPMD by marko on 11/24/08 5:02 PM

	private String baseURL;

	private XMLStreamReader reader;

	private int countedRepos = 0;

	private String currentRepoPath = null;

	private HttpConnector httpConnector;

	@Override

	public boolean hasNext() {

		return currentRepoPath != null;

	}

	@Override

	public String next() {

		if (currentRepoPath == null) throw new NoSuchElementException();

		try {

			String repoInfo = getRepositoryInfo(currentRepoPath);

			return repoInfo;

		} finally {

			currentRepoPath = moveToNextRepo();

		}

	}

	@Override

	public void remove() {

		throw new UnsupportedOperationException();

	}

	@Override

	public Iterator<String> iterator() {

		return this;

	}

	public Re3DataRepositoriesIterator(final InputStream xmlInputStream, final String baseUrl, final HttpConnector httpConnector) throws CollectorServiceException {

		this.httpConnector = httpConnector;

		XMLInputFactory factory = XMLInputFactory.newInstance();

		try {

			reader = factory.createXMLStreamReader(xmlInputStream);

		} catch (XMLStreamException e) {

			throw new CollectorServiceException(e);

		}

		baseURL = baseUrl;

		// try to fetch the 1st

		currentRepoPath = moveToNextRepo();

	}

	private String getNextRepositoryPath() {

		return reader.getAttributeValue(null, "href");

	}

	private String moveToNextRepo() {

		try {

			while (reader.hasNext()) {

				int event = reader.next();

				if (event == XMLStreamConstants.START_ELEMENT) {

					String elementName = reader.getLocalName();

					if (elementName.equals("link")) {

						String repoPath = getNextRepositoryPath();

						log.debug(String.format("Found %s repositories. The last has link %s", ++countedRepos, repoPath));

						return repoPath;

					}

				}

			}

			log.info("Seems there are no more repository to iterate on. Total: " + countedRepos);

			return null;

		} catch (XMLStreamException e) {

			throw new CollectorServiceRuntimeException(e);

		}

	}

	private String getRepositoryInfo(final String repositoryPath) throws CollectorServiceRuntimeException {

		String targetURL = repositoryPath;

		if(!repositoryPath.startsWith(baseURL))

			targetURL = baseURL + repositoryPath;

		try {

			return getHttpConnector().getInputSource(targetURL);

		} catch (CollectorServiceException e) {

			throw new CollectorServiceRuntimeException("OOOPS something bad happen getting repo info from " + targetURL, e);

		}

	}

	public String getBaseURL() {

		return baseURL;

	}

	public void setBaseURL(final String baseURL) {

		this.baseURL = baseURL;

	}

	public int getCountedRepos() {

		return countedRepos;

	}

	public void setCountedRepos(final int countedRepos) {

		this.countedRepos = countedRepos;

	}

	public XMLStreamReader getReader() {

		return reader;

	}

	public void setReader(final XMLStreamReader reader) {

		this.reader = reader;

	}

	public String getCurrentRepoPath() {

		return currentRepoPath;

	}

	public void setCurrentRepoPath(final String currentRepoPath) {

		this.currentRepoPath = currentRepoPath;

	}

	public HttpConnector getHttpConnector() {

		return httpConnector;

	}

	public void setHttpConnector(final HttpConnector httpConnector) {

		this.httpConnector = httpConnector;

	}

}