added support for GeoJSON to geometry collections

src/main/java/com/esri/core/geometry/ogc/OGCConcreteGeometryCollection.java

@@ -5,6 +5,11 @@
 import com.esri.core.geometry.GeometryCursor;
 import com.esri.core.geometry.Polygon;
 import com.esri.core.geometry.SpatialReference;
+import com.esri.core.geometry.Operator;
+import com.esri.core.geometry.JsonCursor;
+import com.esri.core.geometry.OperatorFactoryLocal;
+import com.esri.core.geometry.OperatorExportToGeoJson;
+
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
 import java.util.ArrayList;
@@ -323,4 +328,34 @@ public OGCGeometry convertToMulti()
 	public String asJson() {
 		throw new UnsupportedOperationException();
 	}
+
+	@Override
+	public String asGeoJson() {
+		StringBuilder sb = new StringBuilder();
+
+		OperatorExportToGeoJson op = (OperatorExportToGeoJson) OperatorFactoryLocal
+				.getInstance().getOperator(Operator.Type.ExportToGeoJson);
+		JsonCursor cursor = op.execute(this.esriSR, getEsriGeometryCursor());
+
+		sb.append("{\"type\" : \"GeometryCollection\", \"geometries\" : ");
+		String shape = cursor.next();
+		if (shape == null){
+			// geometry collection with empty list of geometries
+			sb.append("[]}");
+			return sb.toString();
+		}
+
+		sb.append("[");
+		sb.append(shape);
+
+		while(true){
+			shape = cursor.next();
+			if(shape == null)
+				break;
+			sb.append(", ").append(shape);
+		}
+
+		sb.append("]}");
+		return sb.toString();
+	}
 }

src/test/java/com/esri/core/geometry/TestGeomToGeoJson.java

@@ -27,13 +27,16 @@
 import com.esri.core.geometry.ogc.OGCMultiPoint;
 import com.esri.core.geometry.ogc.OGCLineString;
 import com.esri.core.geometry.ogc.OGCPolygon;
+import com.esri.core.geometry.ogc.OGCConcreteGeometryCollection;
 import junit.framework.TestCase;
 import org.codehaus.jackson.JsonFactory;
 import org.codehaus.jackson.JsonParser;
 import org.json.JSONException;
 import org.junit.Test;
 
 import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
 
 public class TestGeomToGeoJson extends TestCase {
     OperatorFactoryLocal factory = OperatorFactoryLocal.getInstance();
@@ -358,4 +361,46 @@ public void testEnvelopeGeometryEngine() {
         assertEquals("{\"bbox\":[-180.0,-90.0,180.0,90.0]}", result);
     }
 
+    @Test
+    public void testGeometryCollection(){
+        SpatialReference sr = SpatialReference.create(4326);
+
+        StringBuilder geometrySb = new StringBuilder();
+        geometrySb.append("{\"type\" : \"GeometryCollection\", \"geometries\" : [");
+
+        OGCPoint point = new OGCPoint(new Point(1.0, 1.0), sr);
+        assertEquals("{\"x\":1,\"y\":1,\"spatialReference\":{\"wkid\":4326}}", point.asJson());
+        assertEquals("{\"type\":\"Point\",\"coordinates\":[1.0,1.0]}", point.asGeoJson());
+        geometrySb.append(point.asGeoJson()).append(", ");
+
+        OGCLineString line = new OGCLineString(new Polyline(new Point(1.0, 1.0), new Point(2.0, 2.0)), 0, sr);
+        assertEquals("{\"paths\":[[[1,1],[2,2]]],\"spatialReference\":{\"wkid\":4326}}", line.asJson());
+        assertEquals("{\"type\":\"LineString\",\"coordinates\":[[1.0,1.0],[2.0,2.0]]}", line.asGeoJson());
+        geometrySb.append(line.asGeoJson()).append(", ");
+
+        Polygon p = new Polygon();
+        p.startPath(1.0, 1.0);
+        p.lineTo(2.0, 2.0);
+        p.lineTo(3.0, 1.0);
+        p.lineTo(2.0, 0.0);
+
+        OGCPolygon polygon = new OGCPolygon(p, sr);
+        assertEquals("{\"rings\":[[[1,1],[2,2],[3,1],[2,0],[1,1]]],\"spatialReference\":{\"wkid\":4326}}",
+                polygon.asJson());
+        assertEquals("{\"type\":\"Polygon\",\"coordinates\":[[[1.0,1.0],[2.0,2.0],[3.0,1.0],[2.0,0.0],[1.0,1.0]]]}",
+                polygon.asGeoJson());
+        geometrySb.append(polygon.asGeoJson()).append("]}");
+
+        List<OGCGeometry> geoms = new ArrayList<OGCGeometry>(3);
+        geoms.add(point);geoms.add(line);geoms.add(polygon);
+        OGCConcreteGeometryCollection collection = new OGCConcreteGeometryCollection(geoms, sr);
+        assertEquals(geometrySb.toString(), collection.asGeoJson());
+    }
+
+    @Test
+    public void testEmptyGeometryCollection(){
+        SpatialReference sr = SpatialReference.create(4326);
+        OGCConcreteGeometryCollection collection = new OGCConcreteGeometryCollection(new ArrayList<OGCGeometry>(), sr);
+        assertEquals("{\"type\" : \"GeometryCollection\", \"geometries\" : []}", collection.asGeoJson());
+    }
 }