PathFunctions must exist when compiled. 'size' alias for 'length'.

json-path/src/main/java/com/jayway/jsonpath/internal/function/PathFunctionFactory.java

@@ -37,13 +37,13 @@ public class PathFunctionFactory {
 
         // JSON Entity Functions
         map.put("length", Length.class);
+        map.put("size", Length.class);
 
         FUNCTIONS = Collections.unmodifiableMap(map);
     }
 
     /**
-     * Either provides a pass thru function when the function cannot be properly mapped or otherwise returns the function
-     * implementation based on the name using the internal FUNCTION map
+     * Returns the function by name or throws InvalidPathException if function not found.
      *
      * @see #FUNCTIONS
      * @see PathFunction
@@ -57,18 +57,15 @@ public class PathFunctionFactory {
      * @throws InvalidPathException
      */
     public static PathFunction newFunction(String name) throws InvalidPathException {
-        PathFunction result = new PassthruPathFunction();
-
-        if (null != name && FUNCTIONS.containsKey(name) && PathFunction.class.isAssignableFrom(FUNCTIONS.get(name))) {
+        Class functionClazz = FUNCTIONS.get(name);
+        if(functionClazz == null){
+            throw new InvalidPathException("Function with name: " + name + " does not exists.");
+        } else {
             try {
-                result = (PathFunction)FUNCTIONS.get(name).newInstance();
-            } catch (InstantiationException e) {
-                throw new InvalidPathException("Function of name: " + name + " cannot be created", e);
-            } catch (IllegalAccessException e) {
+                return (PathFunction)functionClazz.newInstance();
+            } catch (Exception e) {
                 throw new InvalidPathException("Function of name: " + name + " cannot be created", e);
             }
         }
-        return result;
-
     }
 }

json-path/src/test/java/com/jayway/jsonpath/DeepScanTest.java

@@ -298,4 +298,10 @@ public class DeepScanTest extends BaseTest {
         assertThat(using(JSON_SMART_CONFIGURATION.addOptions(Option.REQUIRE_PROPERTIES)).parse(animals).read("$..[?(@.mammal == true)].color", List.class)).containsExactly(brown, white);
     }
 
+    @Test
+    public void scan_with_a_function_filter() {
+        List result = JsonPath.parse(JSON_DOCUMENT).read("$..*[?(@.length() > 5)]");
+        assertThat(result).hasSize(1);
+    }
+
 }

json-path/src/test/java/com/jayway/jsonpath/internal/function/JSONEntityPathFunctionTest.java

@@ -49,17 +49,22 @@ public class JSONEntityPathFunctionTest extends BaseFunctionTest {
             "  }\n" +
             "}";
 
+
+
+
     private Configuration conf = Configurations.JSON_SMART_CONFIGURATION;
 
     @Test
     public void testLengthOfTextArray() {
         // The length of JSONArray is an integer
         verifyFunction(conf, "$['text'].length()", TEXT_SERIES, 6);
+        verifyFunction(conf, "$['text'].size()", TEXT_SERIES, 6);
     }
     @Test
     public void testLengthOfNumberArray() {
         // The length of JSONArray is an integer
         verifyFunction(conf, "$.numbers.length()", NUMBER_SERIES, 10);
+        verifyFunction(conf, "$.numbers.size()", NUMBER_SERIES, 10);
     }