ProductTrackerParser.java

package gov.usgs.earthquake.distribution;

import gov.usgs.earthquake.product.ProductId;

import gov.usgs.util.SAXAdapter;
import gov.usgs.util.XmlUtils;

import java.net.InetAddress;
import java.net.URL;

import java.util.Date;
import java.util.LinkedList;
import java.util.List;

import org.xml.sax.Attributes;
import org.xml.sax.SAXException;

/**
 * Parser for ProductTracker responses.
 */
public class ProductTrackerParser extends SAXAdapter {

    /** The tracker that generated the list being parsed. */
    private URL trackerURL;

    /** A list of parsed updates. */
    private List<ProductTrackerUpdate> updates = new LinkedList<ProductTrackerUpdate>();

    /** The current update being parsed. */
    private ProductTrackerUpdate update = null;

    /**
     * Create a new TrackerUpdateParser.
     * @param trackerURL URL that generated the list being parsed
     */
    public ProductTrackerParser(final URL trackerURL) {
        this.trackerURL = trackerURL;
    }

    /**
     * Get the parsed updates.
     * @return list of parsed updates
     */
    public List<ProductTrackerUpdate> getUpdates() {
        return updates;
    }

    /**
     * SAXAdapter start element handler.
     *
     * @param uri
     *            element uri.
     * @param localName
     *            element localName.
     * @param qName
     *            element qName.
     * @param attributes
     *            element attributes.
     * @throws SAXException
     *             if there is an error.
     */
    public void onStartElement(final String uri, final String localName,
            final String qName, final Attributes attributes)
            throws SAXException {
        if (localName.equals("update")) {
            try {
                Long sequenceNumber = Long.valueOf(XmlUtils.getAttribute(
                        attributes, uri, "sequenceNumber"));
                Date created = XmlUtils.getDate(XmlUtils.getAttribute(
                        attributes, uri, "created"));
                InetAddress host = InetAddress.getByName(XmlUtils.getAttribute(
                        attributes, uri, "host"));
                ProductId id = new ProductId(XmlUtils.getAttribute(attributes,
                        uri, "source"), XmlUtils.getAttribute(attributes,
                                uri, "type"), XmlUtils.getAttribute(attributes, uri,
                        "code"), XmlUtils.getDate(XmlUtils.getAttribute(
                        attributes, uri, "updateTime")));
                String className = XmlUtils.getAttribute(attributes, uri,
                        "className");
                update = new ProductTrackerUpdate(trackerURL, sequenceNumber,
                        created, host, id, className, null);
            } catch (Exception e) {
                throw new SAXException(e);
            }
        }
    }

    /**
     * SAXAdapter end element handler. Content only includes characters that
     * were read from this element, NOT any characters from child elements.
     *
     * @param uri
     *            element uri.
     * @param localName
     *            element localName.
     * @param qName
     *            element qName.
     * @param content
     *            element content.
     * @throws SAXException
     *             if onEndElement throws a SAXException.
     */
    public void onEndElement(final String uri, final String localName,
            final String qName, final String content) throws SAXException {
        // message is element content
        update.setMessage(content);
        // add update to list of parsed updates
        updates.add(update);
        // reset update to null
        update = null;
    }

}