Add SerializableEventListener, make it parent of ConnectorEventListen…

…er (#7980)

Related to vaadin/framework8-issues#264

server/src/main/java/com/vaadin/event/ConnectorEventListener.java

@@ -15,9 +15,18 @@
  */
 package com.vaadin.event;
 
-import java.io.Serializable;
-import java.util.EventListener;
+import com.vaadin.server.ClientConnector;
+import com.vaadin.shared.Connector;
 
-public interface ConnectorEventListener extends EventListener, Serializable {
+/**
+ * Event listener interface for events originating from server side connectors.
+ *
+ * @since 6.0
+ * @author Vaadin Ltd
+ *
+ * @see Connector
+ * @see ClientConnector
+ */
+public interface ConnectorEventListener extends SerializableEventListener {
 
 }

server/src/main/java/com/vaadin/event/SerializableEventListener.java

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2000-2016 Vaadin Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not
+ * use this file except in compliance with the License. You may obtain a copy of
+ * the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package com.vaadin.event;
+
+import java.io.Serializable;
+import java.util.EventListener;
+
+/**
+ * Event listener interface that is serializable.
+ *
+ * @since 8.0
+ * @author Vaadin Ltd
+ */
+public interface SerializableEventListener extends EventListener, Serializable {
+
+}