Github user mike-jumper commented on a diff in the pull request:
https://github.com/apache/incubator-guacamole-client/pull/184#discussion_r143105548
--- Diff:
guacamole-ext/src/main/java/org/apache/guacamole/net/event/listener/Listener.java
---
@@ -0,0 +1,51 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you 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 org.apache.guacamole.net.event.listener;
+
+import org.apache.guacamole.GuacamoleException;
+
+/**
+ * A listener for events that occur in handing various Guacamole requests
+ * such as authentication, tunnel connect/close, etc. Listeners are
registered
+ * through the extension manifest mechanism. When an event occurs,
listeners
+ * are notified in the order in which they are declared in the manifest and
+ * continues until either all listeners have been notified or with the
first
+ * listener that throws a GuacamoleException or other runtime exception.
+ */
+public interface Listener {
+
+ /**
+ * Notifies the recipient that an event has occurred.
+ * <p>
+ * Throwing an exception from an event listener can act to veto an
action in
+ * progress for some event types. See the Javadoc for specific event
types for
+ * details.
+ *
+ * @param event
+ * an object that describes the subject event
+ *
+ * @throws GuacamoleException
+ * If the listener wishes to stop notification of the event to
subsequent
+ * listeners. For some event types, this acts to veto an action in
progress;
+ * e.g. treating a successful authentication as though it failed
--- End diff --
Missing period.
---
