Avoid "java.util.NoSuchElementException: No such Feature exsists" errors when calling Layer.first() with a Filter that returns no Features. Return null instead.

Author: jericks

src/main/groovy/geoscript/layer/Layer.groovy

@@ -658,8 +658,11 @@ class Layer {
         }
         Map params = options.get("params")
         Cursor c = getCursor(filter: filter, sort: sort, params: params)
-        Feature f = c.next()
-        c.close()
+        Feature f = null
+        if (c.hasNext()) {
+            f = c.next()
+            c.close()
+        }
         f
     }
 

src/test/groovy/geoscript/layer/LayerTestCase.groovy

@@ -782,6 +782,7 @@ class LayerTestCase {
         assertEquals "House 1", layer.first(sort: "price ASC").get("name")
         assertEquals "House 2", layer.first(filter: "price > 13 AND price < 14").get("name")
         assertEquals "House 3", layer.first(filter: "price > 13 AND price < 15", sort: "price DESC").get("name")
+        assertNull layer.first(filter: "price < 10")
     }
 
     @Test void transform() {