StreamingKMLBuilder.java

/* (c) 2014 Open Source Geospatial Foundation - all rights reserved
 * (c) 2001 - 2013 OpenPlans
 * This code is licensed under the GPL 2.0 license, available at the root
 * application directory.
 */
package org.geoserver.kml.builder;

import java.util.List;

import org.geoserver.kml.KmlEncodingContext;
import org.geoserver.kml.decorator.KmlDecoratorFactory.KmlDecorator;
import org.geoserver.kml.sequence.PlainFolderSequenceFactory;
import org.geoserver.kml.sequence.SequenceFactory;
import org.geoserver.kml.sequence.SequenceList;
import org.geoserver.platform.ServiceException;

import de.micromata.opengis.kml.v_2_2_0.Document;
import de.micromata.opengis.kml.v_2_2_0.Feature;
import de.micromata.opengis.kml.v_2_2_0.Kml;

/**
 * Builds a lazily evaluated KML document given a encoding context
 * 
 * @author Andrea Aime - GeoSolutions
 */
public class StreamingKMLBuilder {

    /**
     * Builds a lazily evaluated KML document given a encoding context
     * 
     * @param context
     *
     */
    public Kml buildKMLDocument(KmlEncodingContext context) {
        // prepare kml, document and folder
        Kml kml = new Kml();
        Document document = kml.createAndSetDocument();
        String kmltitle = (String) context.getRequest().getFormatOptions().get("kmltitle");
        document.setName(kmltitle);

        // get the callbacks for the document and let them loose
        List<KmlDecorator> decorators = context.getDecoratorsForClass(Document.class);
        for (KmlDecorator decorator : decorators) {
            document = (Document) decorator.decorate(document, context);
            if (document == null) {
                throw new ServiceException("Coding error in decorator " + decorator
                        + ", document objects cannot be set to null");
            }
        }

        // create a generator that will generate a folder and feature dumps/ground overlays for each
        // layer
        SequenceFactory<Feature> generatorFactory = new PlainFolderSequenceFactory(context);
        SequenceList<Feature> folders = new SequenceList<Feature>(generatorFactory);
        context.addFeatures(document, folders);

        return kml;
    }

    
}