Merge pull request #195 from Esri/stolstov/convexhull_194

Fix convex hull crash for collection of polygons

Author: stolstov

.gitignore

@@ -35,3 +35,4 @@ ehthumbs.db
 Thumbs.db
 target/*
 /bin/
+/target/

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

@@ -444,13 +444,13 @@ else if (geom.getType() == Geometry.Type.Point) {
 		}
 
 		if (!polygon.isEmpty()) {
-			if (!resultGeom.isEmpty()) {
+			if (resultGeom != null && !resultGeom.isEmpty()) {
 				Geometry[] geoms = { resultGeom, polygon };
 				resultGeom = OperatorConvexHull.local().execute(
 						new SimpleGeometryCursor(geoms), true, null).next();
 			}
 			else {
-				resultGeom = polygon;
+				resultGeom = OperatorConvexHull.local().execute(polygon, null);
 			}
 		}
 

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

@@ -1059,4 +1059,14 @@ public void testHullIssueGithub172() {
 		}
 	}
 
+	@Test
+	public void testHullIssueGithub194() {
+		{
+			//empty
+			OGCGeometry geom = OGCGeometry.fromText("GEOMETRYCOLLECTION(POLYGON EMPTY, POLYGON((0 0, 1 0, 1 1, 0 0)), POLYGON((-10 -10, 10 -10, 10 10, -10 10, -10 -10), (-5 -5, -5 5, 5 5, 5 -5, -5 -5)))");
+			OGCGeometry result = geom.convexHull();
+			String text = result.asText();
+			assertTrue(text.compareTo("POLYGON ((-10 -10, 10 -10, 10 10, -10 10, -10 -10))") == 0);
+		}
+	}
 }