DescribeLayerKvpRequestReader.java

/* Copyright (c) 2001 - 2007 TOPP - www.openplans.org.  All rights reserved.
 * This code is licensed under the GPL 2.0 license, availible at the root
 * application directory.
 */
package org.vfny.geoserver.wms.requests;

import java.util.List;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.logging.Level;
import java.util.logging.Logger;

import javax.servlet.http.HttpServletRequest;

import org.geoserver.catalog.LayerInfo;
import org.geoserver.platform.ServiceException;
import org.geoserver.wms.MapLayerInfo;
import org.geoserver.wms.WMS;
import org.geoserver.wms.WMSInfo;
import org.vfny.geoserver.Request;
import org.vfny.geoserver.wms.WmsException;

/**
 * Parses a DescribeLayer request, wich consists only of a list of layer names, given by the
 * <code>"LAYER"</code> parameter.
 * 
 * 
 * @author Gabriel Roldan, Axios Engineering
 * @version $Id$
 */
public class DescribeLayerKvpRequestReader extends WmsKvpRequestReader {
    /** package's logger */
    private static final Logger LOGGER = org.geotools.util.logging.Logging
            .getLogger(DescribeLayerKvpRequestReader.class.getPackage().getName());

    private WMS wms;

    /**
     * Constructs a new DescribeLayer request parser.
     * 
     * @param params
     * @param service
     *            The wms service config.
     */
    public DescribeLayerKvpRequestReader(Map params, WMS wms) {
        super(params, wms);
        this.wms = wms;
    }

    /**
     * Does the request parsing and constructs a <code>DescribeLayerRequest</code>, wich holds the
     * requiered layers as <code>FeatureTypeInfo</code> references.
     * 
     * @param request
     *            the original request.
     * 
     * @return the parsed and validated <code>DescribeLayerRequest</code>
     * 
     * @throws ServiceException
     *             see "throws WmsException"...
     * @throws WmsException
     *             if no layers has been requested, or one of the requested layers does not exists
     *             on this server instance, or the version parameter was not provided.
     */
    public Request getRequest(HttpServletRequest request) throws ServiceException {
        if (request == null) {
            throw new NullPointerException("request");
        }

        DescribeLayerRequest req = new DescribeLayerRequest(wms);
        req.setHttpServletRequest(request);

        final String version = getValue("VERSION");
        if (null == version) {
            // spec allows to use custom exception codes, so we'll use
            // NoVersionInfo here. No need to define it as a DTD extension
            // though
            throw new WmsException("Version parameter not provided for DescribeLayer operation",
                    "NoVersionInfo", getClass().getSimpleName());
        }

        if (!wms.getVersion().equals(version)) {
            // spec allows to use custom exception codes, so we'll use
            // InvalidVersion here. No need to define it as a DTD extension
            // though
            throw new WmsException("Wrong value for version parameter: " + version
                    + ". This server accetps version " + getWMS().getVersion(), "InvalidVersion",
                    getClass().getSimpleName());
        }

        req.setVersion(version);

        String layersParam = getValue("LAYERS");

        if (LOGGER.isLoggable(Level.FINE)) {
            LOGGER.fine(layersParam);
        }

        List<String> layers = readFlat(layersParam, INNER_DELIMETER);

        if (LOGGER.isLoggable(Level.FINE)) {
            LOGGER.fine(layers.toString());
        }

        int layerCount = layers.size();

        if (layerCount == 0) {
            throw new WmsException("No LAYERS has been requested", "NoLayerRequested", getClass()
                    .getName());
        }

        String layerName = null;
        MapLayerInfo layer = null;

        for (int i = 0; i < layerCount; i++) {
            layerName = (String) layers.get(i);

            if (LOGGER.isLoggable(Level.FINE)) {
                LOGGER.fine(new StringBuffer("Looking for layer ").append(layerName).toString());
            }

            if (LOGGER.isLoggable(Level.FINE)) {
                LOGGER.fine("looking featuretypeinfos");
            }

            LayerInfo layerInfo = wms.getLayerByName(layerName);
            if (layerInfo == null) {
                throw new WmsException(layerName + ": no such layer on this server",
                        "LayerNotDefined",  getClass().getSimpleName());
            }
            layer = new MapLayerInfo(layerInfo);
            req.addLayer(layer);
            if (LOGGER.isLoggable(Level.FINE)) {
                LOGGER.fine(new StringBuffer(layerName).append(" found").toString());
            }

        }

        if (LOGGER.isLoggable(Level.FINE)) {
            LOGGER.fine(new StringBuffer("parsed request ").append(req).toString());
        }

        return req;
    }
}