Metacat

/**

 *  '$RCSfile$'

 *  Copyright: 2000 Regents of the University of California and the

 *  National Center for Ecological Analysis and Synthesis

 *

 *  Author: Matthew Perry

 *  '$Date$'

 *  '$Revision$'

 *

 *  This program is free software; you can redistribute it and/or modify

 *  it under the terms of the GNU General Public License as published by

 *  the Free Software Foundation; either version 2 of the License, or

 *  (at your option) any later version.

 *  

 *  This program is distributed in the hope that it will be useful,

 *  but WITHOUT ANY WARRANTY; without even the implied warranty of

 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 *  GNU General Public License for more details.

 *

 *  You should have received a copy of the GNU General Public License

 *  along with this program; if not, write to the Free Software

 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 *

 *  Purpose: Servlet to generate a styled layer descriptor (SLD)

 *           with a filter to restrict features on

 *           a WMS map to given docids

 *

 *  Status: Currently this is just a working stub

 *          with some hardcoded values. Since this needs to be

 *          fired off on every map redraw, we'll need a way to make 

 *          the generation of docid list very efficient. 

 *

 *  Usage: Append the URL as an "SLD" to any WMS GetMap request

 *    ex: http://server/context/wms?...&SLD=http://server/context/sldfactory?originalSld=data_points_style

import edu.ucsb.nceas.metacat.MetaCatUtil;

import java.io.FileNotFoundException;

import java.util.Vector;

    String dataset = request.getParameter("originalSld"); 

    String filename = MetaCatUtil.getOption("certPath") + "data/styles/" + dataset;

    try {

	String sld = getSld(filename);

        System.out.println(sld);

	response.setContentType("text/xml");

	response.getWriter().write(sld);

    } catch (FileNotFoundException fnf) {

	fnf.printStackTrace();

    } catch (Exception e) {

        e.printStackTrace();

    }

   * The sld file is specified without path and 

   * must exist within geoserver's styles folder (context/data/styles/*)

  private String getSld(String filename) throws FileNotFoundException

	    Vector allowedDocids = new Vector();

	    /*

	     * TODO : 

	     *  Get the list of allowable docids due to 

	     *    access contraints (based on current logged-in user)

	     *    skin filtering (eg organization name) 

	     *    existing non-spatial query (eg taxonomic query)

	     *

	     *  These could ideally be cached as session variables to improve

	     *  speed over running expensive SQL queries on 

	     *  each map redraw.

	     *

	     * Combined, these will be a vector of allowed docids that

	     * are to be displayed on the map

	     *

	     * Below is just a hardcoded example of the above...

	     *

	     */

	    allowedDocids.add("nceas.288");

	    allowedDocids.add("nrs.720");

	    String rulesString = "";

		    DocumentBuilder builder = factory.newDocumentBuilder();

		    document = builder.parse( new File(filename) );	       

		    Element root = document.getDocumentElement();

		    NodeList elemList = document.getElementsByTagName("Rule");

		    Node ruleNode = elemList.item(0);

		    // Get the Element/node comprising the ogc:Filter for all of the above

		    Element filterElement = getFilterElement(document,allowedDocids);

		    // Append the Filter to the ruleNode

		    ruleNode.appendChild(filterElement);

		    // Write new DOM as a string

		    rulesString = XMLUtilities.getDOMTreeAsString((Node) root, true);

	    } 

   * @param docids 	Vector of documents allowed in the map.

  private Element getFilterElement(Document inDoc, Vector docids) 

	  Element orElem = inDoc.createElement("ogc:Or");

	  String docid = "";

	  // Begin loop thru vector of allowed docids

	  for (int i = 0; i < docids.size(); i++) {

		  Element opElem = inDoc.createElement("ogc:PropertyIsEqualTo");

		  Element propertyElem = inDoc.createElement("ogc:PropertyName");

		  Text propertyText = inDoc.createTextNode("docid");

		  propertyElem.appendChild(propertyText);

		  Element literalElem = inDoc.createElement("ogc:Literal");	  

		  docid = (String)docids.elementAt(i);

		  Text literalText = inDoc.createTextNode(docid); 

		  literalElem.appendChild(literalText);

		  opElem.appendChild(propertyElem);

		  opElem.appendChild(literalElem);

		  orElem.appendChild(opElem);

		  // END LOOP

	  }

	  filterElem.appendChild(orElem);