URLNotificationParser.java

/*
 * URLNotificationParser
 */
package gov.usgs.earthquake.distribution;

import java.net.URL;
import java.util.Date;

import gov.usgs.earthquake.product.ProductId;
import gov.usgs.util.SAXAdapter;
import gov.usgs.util.XmlUtils;

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

public class URLNotificationParser extends SAXAdapter {

    /** Namespace for product XML */
    public static final String PRODUCT_XML_NAMESPACE = "http://earthquake.usgs.gov/distribution/product";

    /** static var for notification element */
    public static final String NOTIFICATION_ELEMENT = "notification";
    /** attribute for product id */
    public static final String ATTRIBUTE_PRODUCT_ID = "id";
    /** attribute for updated */
    public static final String ATTRIBUTE_PRODUCT_UPDATED = "updated";
    /** attribute for trackerURL */
    public static final String ATTRIBUTE_TRACKER_URL = "trackerURL";
    /** attribute for expires */
    public static final String ATTRIBUTE_EXPIRES = "expires";
    /** attribute for url */
    public static final String ATTRIBUTE_URL = "url";

    /** The parsed notification. */
    private URLNotification notification;

    /**
     * Construct a URLNotificationParser. This class is not intended to be
     * instantiated directly. Instead, use the static URLNotification.parse
     * method.
     */
    protected URLNotificationParser() {
    }

    /**
     * @return the parsed notification
     */
    public URLNotification getNotification() {
        return notification;
    }

    /**
     * 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 (!uri.equals(PRODUCT_XML_NAMESPACE)) {
            return;
        }

        if (localName.equals(NOTIFICATION_ELEMENT)) {
            ProductId id = ProductId.parse(XmlUtils.getAttribute(
                    attributes, uri, ATTRIBUTE_PRODUCT_ID));
            id.setUpdateTime(XmlUtils.getDate(XmlUtils.getAttribute(
                    attributes, uri, ATTRIBUTE_PRODUCT_UPDATED)));

            URL trackerURL = null;
            try {
                trackerURL = new URL(XmlUtils.getAttribute(attributes, uri,
                        ATTRIBUTE_TRACKER_URL));
            } catch (Exception e) {
                throw new SAXException("Unable to parse tracker url", e);
            }

            Date expirationDate = XmlUtils.getDate(XmlUtils.getAttribute(
                    attributes, uri, ATTRIBUTE_EXPIRES));

            URL productURL = null;
            try {
                productURL = new URL(XmlUtils.getAttribute(attributes, uri,
                        ATTRIBUTE_URL));
            } catch (Exception e) {
                throw new SAXException("Unable to parse product url", e);
            }

            notification = new URLNotification(id, expirationDate,
                    trackerURL, productURL);
        }
    }

}