EventDataXMLHandler.java

package gov.usgs.earthquake.dyfi;

import gov.usgs.util.XmlUtils;

import java.util.HashMap;
import java.util.Map;

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

/**
 * Parser for DYFI "eventdata.xml" metadata.
 */
public class EventDataXMLHandler extends DefaultHandler {

    /** XML Element Name for event_data */
    public static final String DYFI_EVENTDATA_ELEMENT = "event_data";
    /** XML Element Name  for event */
    public static final String DYFI_EVENT_ELEMENT = "event";
    /** XML Element Name for cdi_summary */
    public static final String DYFI_CDI_SUMMARY_ELEMENT = "cdi_summary";
    /** XML Element Name for products */
    public static final String DYFI_PRODUCTS_ELEMENT = "products";

    /** Static string to stop parsing before list of products */
    public static final String DYFI_STOP_PARSING_BEFORE_PRODUCTS = "Stop parsing before list of product files.";

    /** Map of XML attributes */
    public static final Map<String, String[]> DYFI_ELEMENT_ATTRIBUTES = new HashMap<String, String[]>();
    static {
        // Statically add all these attributes and associate them to their
        // corresponding elements

        // Currently we only care about the max MMI and number of responses.
        DYFI_ELEMENT_ATTRIBUTES.put(DYFI_CDI_SUMMARY_ELEMENT, new String[] {
                DYFIProduct.DYFI_NUM_RESP_PROPERTY,
                DYFIProduct.DYFI_MAX_MMI_PROPERTY });
    }

    private DYFIProduct dyfi = null;

    /**
     * Constructor
     * @param dyfi takes in DYFIProduct
     */
    public EventDataXMLHandler(final DYFIProduct dyfi) {
        this.dyfi = dyfi;
    }

    /** @return DYFIProduct */
    public DYFIProduct getDYFI() {
        return this.dyfi;
    }

    /** @param dyfi Product to set */
    public void setDYFI(final DYFIProduct dyfi) {
        this.dyfi = dyfi;
    }

    /**
     *
     * @param in XML object to parse
     * @return DYFIProduct
     * @throws Exception if exception message equals stop_parsing string
     */
    public DYFIProduct parse(final Object in) throws Exception {
        try {
            XmlUtils.parse(in, this);
        } catch (Exception e) {
            if (!DYFI_STOP_PARSING_BEFORE_PRODUCTS.equals(e.getMessage())) {
                throw e;
            }
        }
        return getDYFI();
    }

    public final void startElement(final String uri, final String localName,
            final String qName, final Attributes attributes)
            throws SAXException {

        if (localName != null && DYFI_PRODUCTS_ELEMENT.equals(localName)) {
            // We don't need the list of product files at this time.
            throw new SAXException(DYFI_STOP_PARSING_BEFORE_PRODUCTS);
        }

        if (DYFI_CDI_SUMMARY_ELEMENT.equals(localName)) {
            dyfi.setNumResponses(attributes
                    .getValue(DYFIProduct.DYFI_NUM_RESP_ATTRIBUTE));
            dyfi.setMaxMMI(attributes
                    .getValue(DYFIProduct.DYFI_MAX_MMI_ATTRIBUTE));
        }
    }
}