GridXMLHandler.java

package gov.usgs.earthquake.shakemap;

import gov.usgs.util.XmlUtils;

import java.util.HashMap;

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

/**
 * Parser for ShakeMap grid.xml metadata.
 *
 * Accepts a ShakeMap object and updates the properties of that product based on
 * the product's grid.xml file.
 */
public class GridXMLHandler extends DefaultHandler {

    // ShakeMap grid parameters
        /** Element for shakemap grid */
        public static final String SHAKEMAPGRID_ELEMENT = "shakemap_grid";
        /** Shakemap grid id */
        public static final String SHAKEMAPGRID_ID = "shakemap_id";
        /** Shakemap grid originator */
        public static final String SHAKEMAPGRID_ORIGINATOR = "shakemap_originator";
        /** Shakemap grid process timestamp */
        public static final String SHAKEMAPGRID_TIMESTAMP = "process_timestamp";
        /** Shakemap grid version */
        public static final String SHAKEMAPGRID_VERSION = "shakemap_version";
        /** Shakemap grid event type */
        public static final String SHAKEMAPGRID_EVENT_TYPE = "shakemap_event_type";
        /** Shakemap grid event/map status */
        public static final String SHAKEMAPGRID_EVENT_STATUS = "map_status";

        // ShakeMap event parameters
        /** Element for event */
        public static final String EVENT_ELEMENT = "event";
        /** Event latitude */
        public static final String EVENT_LATITUDE = "lat";
        /** Event longitude */
        public static final String EVENT_LONGITUDE = "lon";
        /** Event magnitude */
        public static final String EVENT_MAGNITUDE = "magnitude";
        /** Event timestamp */
        public static final String EVENT_TIMESTAMP = "event_timestamp";
        /** Event description */
        public static final String EVENT_DESCRIPTION = "event_description";
        /** Event depth */
        public static final String EVENT_DEPTH = "depth";

        // These are new parameters used by GSM when it is contributing to a
        // different
        // network as a backup
        /** GSM Parameter when using a different network as a backup */
        public static final String EVENT_NETWORK = "event_network";
        /** GSM Parameter when using a different network as a backup */
        public static final String EVENT_ID = "event_id";

        // ShakeMap gridspec parameters
        /** Element for grid specification */
        public static final String GRIDSPEC_ELEMENT = "grid_specification";
        /** gridspec longitude min */
        public static final String GRIDSPEC_LONMIN = "lon_min";
        /** gridspec longitude max */
        public static final String GRIDSPEC_LONMAX = "lon_max";
        /** gridspec latitude min */
        public static final String GRIDSPEC_LATMIN = "lat_min";
        /** gridspec latitude max */
        public static final String GRIDSPEC_LATMAX = "lat_max";

        /** XML for SHAKEMAPGRID_ELEMENT */
        public static final String SHAKEMAPGRID_ELEMENT_XML = SHAKEMAPGRID_ELEMENT;
        /** XML for SHAKEMAPGRID_ID */
        public static final String SHAKEMAPGRID_ID_XML =  SHAKEMAPGRID_ELEMENT+ "[" + SHAKEMAPGRID_ID + "]";
        /** XML for SHAKEMAPGRID_ORIGINATOR */
        public static final String SHAKEMAPGRID_ORIGINATOR_XML = SHAKEMAPGRID_ELEMENT + "[" + SHAKEMAPGRID_ORIGINATOR + "]";
        /** XML for SHAKEMAPGRID_TIMESTAMP */
        public static final String SHAKEMAPGRID_TIMESTAMP_XML = SHAKEMAPGRID_ELEMENT + "[" + SHAKEMAPGRID_TIMESTAMP + "]";
        /** XML for SHAKEMAPGRID_VERSION */
        public static final String SHAKEMAPGRID_VERSION_XML = SHAKEMAPGRID_ELEMENT+ "[" + SHAKEMAPGRID_VERSION + "]";
        /** XML for SHAKEMAPGRID_EVENT_TYPE */
        public static final String SHAKEMAPGRID_EVENT_TYPE_XML = SHAKEMAPGRID_ELEMENT+ "[" + SHAKEMAPGRID_EVENT_TYPE + "]";
        /** XML for SHAKEMAPGRID_EVENT_STATUS */
        public static final String SHAKEMAPGRID_EVENT_STATUS_XML = SHAKEMAPGRID_ELEMENT+ "[" + SHAKEMAPGRID_EVENT_STATUS + "]";

        /** XML for EVENT_ELEMENT */
        public static final String EVENT_ELEMENT_XML = EVENT_ELEMENT;
        /** XML for EVENT_LATITUDE */
        public static final String EVENT_LATITUDE_XML = EVENT_ELEMENT + "[" + EVENT_LATITUDE + "]";
        /** XML for EVENT_LONGITUDE */
        public static final String EVENT_LONGITUDE_XML = EVENT_ELEMENT+ "[" + EVENT_LONGITUDE + "]";
        /** XML for EVENT_MAGNITUDE */
        public static final String EVENT_MAGNITUDE_XML = EVENT_ELEMENT+ "[" + EVENT_MAGNITUDE + "]";
        /** XML for EVENT_TIMESTAMP */
        public static final String EVENT_TIMESTAMP_XML = EVENT_ELEMENT+ "[" + EVENT_TIMESTAMP + "]";
        /** XML for EVENT_DESCRIPTION */
        public static final String EVENT_DESCRIPTION_XML = EVENT_ELEMENT+ "[" + EVENT_DESCRIPTION + "]";
        /** XML for EVENT_DEPTH */
        public static final String EVENT_DEPTH_XML = EVENT_ELEMENT+ "[" + EVENT_DEPTH + "]";
        /** XML for EVENT_NETWORK */
        public static final String EVENT_NETWORK_XML = EVENT_ELEMENT + "[" + EVENT_NETWORK + "]";
        /** XML for EVENT_ID */
        public static final String EVENT_ID_XML = EVENT_ELEMENT + "[" + EVENT_ID + "]";

        /** XML for GRIDSPEC_ELEMENT */
        public static final String GRIDSPEC_ELEMENT_XML = GRIDSPEC_ELEMENT;
        /** XML for GRIDSPEC_LONMIN */
        public static final String GRIDSPEC_LONMIN_XML = GRIDSPEC_ELEMENT+ "[" + GRIDSPEC_LONMIN + "]";
        /** XML for GRIDSPEC_LONMAX */
        public static final String GRIDSPEC_LONMAX_XML = GRIDSPEC_ELEMENT+ "[" + GRIDSPEC_LONMAX + "]";
        /** XML for GRIDSPEC_LATMIN */
        public static final String GRIDSPEC_LATMIN_XML = GRIDSPEC_ELEMENT+ "[" + GRIDSPEC_LATMIN + "]";
        /** XML for GRIDSPEC_LATMAX */
        public static final String GRIDSPEC_LATMAX_XML = GRIDSPEC_ELEMENT+ "[" + GRIDSPEC_LATMAX + "]";

    // ShakeMap griddata parameters
    /** Element for Shakemap griddata */
    public static final String GRIDDATA_ELEMENT = "grid_data";
    /** Shakemap griddata parameter to stop parsing before */
    public static final String STOP_PARSING_BEFORE_GRIDDATA =
            "Stop parsing before grid data.";

    private HashMap<String, String> grid = new HashMap<String, String>();

    /**
     * Construct a new SAX Handler for an grid.xml document.
     */
    public GridXMLHandler() {}

    /**
     * @param in
     *            - the file or stream to parse
     * @return the ShakeMap associated with this XML handler
     * @throws Exception if error occurs
     */
    public HashMap<String, String> parse(final Object in) throws Exception {
        try {
            XmlUtils.parse(in, this);
        } catch (Exception se) {
            if (!se.getMessage().equals(STOP_PARSING_BEFORE_GRIDDATA)) {
                throw se;
            }
        }
        return this.grid;
    }

    /**
     * @return the parsed info.
     */
    public HashMap<String, String> getInfo() {
        return this.grid;
    }


    /**
     * Read grid, event, and gridspec element attributes.
     *
     * @param uri namespace of element.
     * @param localName name of element.
     * @param qName qualified name of element.
     * @param attributes element attributes.
     * @throws SAXException when griddata element is reached, to stop parsing.
     */
    public final void startElement(final String uri, final String localName,
            final String qName, final Attributes attributes)
            throws SAXException {

        if (localName != null && GRIDDATA_ELEMENT.equals(localName)) {
            // don't read the whole grid
            throw new SAXException(STOP_PARSING_BEFORE_GRIDDATA);
        }

        if (localName.equals(SHAKEMAPGRID_ELEMENT)) {
            this.grid.put(SHAKEMAPGRID_ORIGINATOR_XML, attributes.getValue(SHAKEMAPGRID_ORIGINATOR));
            this.grid.put(SHAKEMAPGRID_ID_XML, attributes.getValue(SHAKEMAPGRID_ID));
            this.grid.put(SHAKEMAPGRID_TIMESTAMP_XML, attributes.getValue(SHAKEMAPGRID_TIMESTAMP));
            this.grid.put(SHAKEMAPGRID_VERSION_XML, attributes.getValue(SHAKEMAPGRID_VERSION));
            this.grid.put(SHAKEMAPGRID_EVENT_TYPE_XML, attributes.getValue(SHAKEMAPGRID_EVENT_TYPE));
            this.grid.put(SHAKEMAPGRID_EVENT_STATUS_XML, attributes.getValue(SHAKEMAPGRID_EVENT_STATUS));
        } else if (localName.equals(EVENT_ELEMENT)) {
            this.grid.put(EVENT_LATITUDE_XML, attributes.getValue(EVENT_LATITUDE));
            this.grid.put(EVENT_LONGITUDE_XML, attributes.getValue(EVENT_LONGITUDE));
            this.grid.put(EVENT_MAGNITUDE_XML , attributes.getValue(EVENT_MAGNITUDE));
            this.grid.put(EVENT_DEPTH_XML, attributes.getValue(EVENT_DEPTH));
            this.grid.put(EVENT_TIMESTAMP_XML, attributes.getValue(EVENT_TIMESTAMP));
            this.grid.put(EVENT_DESCRIPTION_XML, attributes.getValue(EVENT_DESCRIPTION));
            this.grid.put(EVENT_NETWORK_XML, attributes.getValue(EVENT_NETWORK));
            this.grid.put(EVENT_ID_XML, attributes.getValue(EVENT_ID));
        } else if (localName.equals(GRIDSPEC_ELEMENT)) {
            this.grid.put(GRIDSPEC_LONMIN_XML, attributes.getValue(GRIDSPEC_LONMIN));
            this.grid.put(GRIDSPEC_LATMIN_XML, attributes.getValue(GRIDSPEC_LATMIN));
            this.grid.put(GRIDSPEC_LONMAX_XML, attributes.getValue(GRIDSPEC_LONMAX));
            this.grid.put(GRIDSPEC_LATMAX_XML, attributes.getValue(GRIDSPEC_LATMAX));
        }
    }
}