1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 *
19 */
20 package org.apache.mina.handler.demux;
21
22 import org.apache.mina.core.session.IoSession;
23
24 /**
25 * A handler interface that {@link DemuxingIoHandler} forwards
26 * <code>exceptionCaught</code> events to. You have to register your
27 * handler with the type of exception you want to get notified using
28 * {@link DemuxingIoHandler#addExceptionHandler(Class, ExceptionHandler)}.
29 *
30 * @param <E> The exception type
31 *
32 * @author <a href="http://mina.apache.org">Apache MINA Project</a>
33 */
34 public interface ExceptionHandler<E extends Throwable> {
35 /**
36 * A {@link ExceptionHandler} that does nothing. This is useful when
37 * you want to ignore an exception of a specific type silently.
38 */
39 ExceptionHandler<Throwable> NOOP = new ExceptionHandler<Throwable>() {
40 /**
41 * {@inheritDoc}
42 */
43 @Override
44 public void exceptionCaught(IoSession session, Throwable cause) {
45 // Do nothing
46 }
47 };
48
49 /**
50 * A {@link ExceptionHandler} that closes the session immediately.
51 * This is useful when you want to close the session when an exception of
52 * a specific type is raised.
53 */
54 ExceptionHandler<Throwable> CLOSE = new ExceptionHandler<Throwable>() {
55 /**
56 * {@inheritDoc}
57 */
58 @Override
59 public void exceptionCaught(IoSession session, Throwable cause) {
60 session.closeNow();
61 }
62 };
63
64 /**
65 * Invoked when the specific type of exception is caught from the
66 * specified <code>session</code>.
67 *
68 * @param session The current session
69 * @param cause the exception's cause
70 * @throws Exception If we can't process the event
71 */
72 void exceptionCaught(IoSession session, E cause) throws Exception;
73 }