javafx: accept no params handlers (IDEA-102017)

plugins/javaFX/javaFX-CE/testSrc/org/jetbrains/plugins/javaFX/fxml/JavaFXHighlightingTest.java

@@ -93,6 +93,11 @@ public class JavaFXHighlightingTest extends DaemonAnalyzerTestCase {
     doDoTest(false, false);
   }
 
+  public void testNoParamsHandler() throws Exception {
+    configureByFiles(null, getTestName(true) + ".fxml", getTestName(false) + ".java");
+    doDoTest(false, false);
+  }
+
   private void doTestIdController() throws Exception {
     final String controllerClassName = getTestName(false) + "Controller";
     configureByFiles(null, getTestName(true) + ".fxml", controllerClassName + ".java");

plugins/javaFX/src/org/jetbrains/plugins/javaFX/fxml/refs/JavaFxEventHandlerReference.java

@@ -79,6 +79,7 @@ public class JavaFxEventHandlerReference extends PsiReferenceBase<XmlAttributeVa
           return true;
         }
       }
+      return parameters.length == 0;
     }
     return false;
   }

plugins/javaFX/testData/highlighting/NoParamsHandler.java

@@ -0,0 +1,4 @@
+public class Controller {
+  public void sayHelloWorld() {
+  }
+}

plugins/javaFX/testData/highlighting/noParamsHandler.fxml

@@ -0,0 +1,5 @@
+<?import javafx.scene.control.*?>
+<?import javafx.scene.layout.GridPane?>
+<GridPane xmlns:fx="http://javafx.com/fxml" fx:controller="Controller">
+    <Button onAction="#sayHelloWorld"/>
+</GridPane>