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.filter.executor;
21
22 import java.util.EventListener;
23
24 import org.apache.mina.core.session.IoEvent;
25
26 /**
27 * Listens and filters all event queue operations occurring in
28 * {@link OrderedThreadPoolExecutor} and {@link UnorderedThreadPoolExecutor}.
29 *
30 * @author <a href="http://mina.apache.org">Apache MINA Project</a>
31 */
32 public interface IoEventQueueHandler extends EventListener {
33
34 /**
35 * A dummy handler which always accepts event doing nothing particular.
36 */
37 IoEventQueueHandlerentQueueHandler.html#IoEventQueueHandler">IoEventQueueHandler NOOP = new IoEventQueueHandler() {
38 /**
39 * {@inheritDoc}
40 */
41 @Override
42 public boolean accept(Object source, IoEvent event) {
43 return true;
44 }
45
46 /**
47 * {@inheritDoc}
48 */
49 @Override
50 public void offered(Object source, IoEvent event) {
51 // NOOP
52 }
53
54 /**
55 * {@inheritDoc}
56 */
57 @Override
58 public void polled(Object source, IoEvent event) {
59 // NOOP
60 }
61 };
62
63 /**
64 * @return <tt>true</tt> if and only if the specified <tt>event</tt> is
65 * allowed to be offered to the event queue. The <tt>event</tt> is dropped
66 * if <tt>false</tt> is returned.
67 *
68 * @param source The source of event
69 * @param event The received event
70 */
71 boolean accept(Object source, IoEvent event);
72
73 /**
74 * Invoked after the specified <tt>event</tt> has been offered to the
75 * event queue.
76 *
77 * @param source The source of event
78 * @param event The received event
79 */
80 void offered(Object source, IoEvent event);
81
82 /**
83 * Invoked after the specified <tt>event</tt> has been polled from the
84 * event queue.
85 *
86 * @param source The source of event
87 * @param event The received event
88 */
89 void polled(Object source, IoEvent event);
90 }