Creates function to know if a jsonPath is a function or not

json-path/src/main/java/com/jayway/jsonpath/JsonPath.java

@@ -496,6 +496,17 @@ public class JsonPath {
         }
     }
 
+    /**
+     * As JsonPath accepts a vary number of functions like min(), max(),
+     * avg(), stddev(), length(), sum(), keys(), concat(X), append(X),
+     * this function will return true if the path is a function
+     *
+     * @return true if the path is a function
+     */
+    public Boolean isFunctionPath() {
+        return path.isFunctionPath();
+    }
+
     // --------------------------------------------------------
     //
     // Static factory methods

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

@@ -304,6 +304,12 @@ public class PathCompilerTest {
         assertThat(compile("$.aaa.foo(5,10,15)").toString()).isEqualTo("$['aaa'].foo(...)");
     }
 
+    @Test
+    public void path_is_a_function() {
+        assertThat(compile("concat($.aaa, $.bbb)").isFunctionPath()).isTrue();
+        assertThat(compile("$.aaa").isFunctionPath()).isFalse();
+    }
+
     @Test(expected = InvalidPathException.class)
     public void array_indexes_must_be_separated_by_commas() {
         compile("$[0, 1, 2 4]");