OGCFeatureEncoder.java

/**
 * Copyright (C) 2012 52°North Initiative for Geospatial Open Source Software GmbH
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.n52.sos.encoder;

import java.io.IOException;
import java.util.Collection;

import javax.activation.UnsupportedDataTypeException;

import org.n52.om.sampling.AQDSample;
import org.n52.om.sampling.Feature;

import com.esri.arcgis.geometry.IGeometry;
import com.esri.arcgis.geometry.Point;

/**
 * @author <a href="mailto:broering@52north.org">Arne Broering</a>
 */
public class OGCFeatureEncoder extends AbstractEncoder {

    /*
     * definition of anchor variables within template files:
     */
    private static String FEATURES = "@features@";
    private static String FEATURE_GML_ID = "@feature-gml-id@";
    private static String FEATURE_POINT = "@feature-point-location@";
    private static String FEATURE_NAME = "@feature-name@";
    private static String FEATURE_SAMPLED = "@feature-sampled-href@";
    private static String FEATURE_DESCRIPTION = "@feature-description@";
    private static String FEATURE_GEOMETRY = "@feature-geometry@";
    private static String FEATURE_NAMESPACE = "@feature-namespace@";
    private static String FEATURE_LOCALID = "@feature-local-id@";
    private static String FEATURE_INLET_HEIGHT = "@feature-inlet-height@";
    private static String FEATURE_BUILDING_DISTANCE = "@feature-building-distance@";
    private static String FEATURE_KERB_DISTANCE = "@feature-kerb-distance@";
    
	private String responseTemplate;
	private String featureTemplate;

    public OGCFeatureEncoder () throws IOException {
    	super();
    	
		responseTemplate = readText(OGCFeatureEncoder.class.getResourceAsStream("template_getfeatureofinterest_response.xml"));
		featureTemplate = readText(OGCFeatureEncoder.class.getResourceAsStream("template_feature.xml"));
    }
    
    public String encodeFeatures(Collection<Feature> featureCollection) throws IOException {
                
        StringBuilder allFeatures = new StringBuilder();
        
        for (Feature feature : featureCollection) {
            
            StringBuilder featureString = new StringBuilder();
            featureString.append(featureTemplate);
            
            if (feature.getGmlId() != null) {
            	replace(featureString, FEATURE_GML_ID, "gml:id=\"" + feature.getGmlId() + "\"");
            }
            else {
            	replace(featureString, FEATURE_GML_ID, "");
            }
            
            if (feature.getGmlId() != null) {
            	replace(featureString, FEATURE_LOCALID, feature.getGmlId());
            }
            else {
            	replace(featureString, FEATURE_LOCALID, "");
            }
            
            if (feature.getUri() != null) {
	            // take the feature URI without everything after '#' as the namespace:
	            String featureNamespace = feature.getUri().toASCIIString();
	            int indexOfDash = featureNamespace.indexOf("#");
	            if (indexOfDash != -1) {
	            	featureNamespace = featureNamespace.substring(0, indexOfDash + 1);
	            }
	            replace(featureString, FEATURE_NAMESPACE, featureNamespace);
            }
            else {
            	replace(featureString, FEATURE_NAMESPACE, "");
            }
            
            if (feature.getShape() != null) {
            	IGeometry geometry = feature.getShape();
	            int dimension  = feature.getShape().getSpatialReference().getZCoordinateUnit() == null ? 2 : 3;
	            int epsgCode   = geometry.getSpatialReference().getFactoryCode();
	            String epsgUrn = "urn:ogc:def:crs:EPSG::" + epsgCode;
	            
            	if (geometry instanceof Point) {
		            Point p = (Point)geometry;
		            replace(featureString, FEATURE_POINT, p.getX() + " " + p.getY());
		            
		            String featureGeometry =
		            "<sams:shape>"
					+	"<gml:Point gml:id=\"SamplingFeaturePoint_" + feature.getLocalId() + "\" srsDimension=\"" + dimension + "\" srsName=\"" + epsgUrn + "\">"
					+		"<gml:pos>" + p.getX() + " " + p.getY() + "</gml:pos>"
					+	"</gml:Point>"
					+"</sams:shape>";
		            
		            replace(featureString, FEATURE_GEOMETRY, featureGeometry);
            	}
            	else {
					throw new UnsupportedDataTypeException("Cannot encode geometry of feature.");
				}
            }
            else {
            	/*
            	 * TODO resolve Feature Geometry via referenced Stations
            	 */
            	replace(featureString, FEATURE_GEOMETRY, "<sams:shape />");
            }
            
            if (feature.getSampledFeature() != null) {
            	replace(featureString, FEATURE_SAMPLED, "<sam:sampledFeature xlink:href=\""+ feature.getSampledFeature() + "\" />");
            } else {
            	replace(featureString, FEATURE_SAMPLED, "<sam:sampledFeature nilReason=\"inapplicable\" />");
            }
            
            if (feature.getName() != null) {
            	replace(featureString, FEATURE_NAME, "<gml:name>" + feature.getName() + "</gml:name>");
            } else {
            	replace(featureString, FEATURE_NAME, "");
            }
            
            if (feature.getDescription() != null) {
            	replace(featureString, FEATURE_DESCRIPTION, "<gml:description>" + feature.getDescription() +"</gml:description>");
            } else {
            	replace(featureString, FEATURE_DESCRIPTION, "");
            }
            
            if (feature instanceof AQDSample) {
                AQDSample aqdSample = (AQDSample) feature;
                replace(featureString, FEATURE_INLET_HEIGHT, aqdSample.getInletHeight()+"");
                replace(featureString, FEATURE_BUILDING_DISTANCE, aqdSample.getBuildingDistance()+"");
                replace(featureString, FEATURE_KERB_DISTANCE, aqdSample.getKerbDistance()+"");
            }
            
            // add features to the allFeatures String
            allFeatures.append(featureString);
        }
        
        String response = responseTemplate.replace(FEATURES, allFeatures);
        
        return response;
    }
    
}