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.service.executor;
21
22 import java.util.concurrent.BlockingQueue;
23 import java.util.concurrent.LinkedBlockingQueue;
24
25 import org.apache.mina.api.IoHandler;
26 import org.slf4j.Logger;
27 import org.slf4j.LoggerFactory;
28
29 /**
30 * Use this executor if you want the {@link IoHandler} events of a session to be executed in order and on the same
31 * thread. In your {@link IoHandler} code you don't need to care about session level concurrency.
32 *
33 * @author <a href="http://mina.apache.org">Apache MINA Project</a>
34 */
35 public final class OrderedHandlerExecutor implements IoHandlerExecutor {
36
37 private static final Logger LOG = LoggerFactory.getLogger(OrderedHandlerExecutor.class);
38
39 private Worker[] workers;
40
41 /**
42 * Create an {@link OrderedHandlerExecutor} with a given number of thread and a given queue size.
43 *
44 * @param workerThreadCount the worker thread count
45 * @param queueSize the size of the queue for each worker thread
46 */
47 public OrderedHandlerExecutor(int workerThreadCount, int queueSize) {
48 LOG.debug("creating OrderedHandlerExecutor workerThreadCount = {} queueSize = {}", workerThreadCount, queueSize);
49 workers = new Worker[workerThreadCount];
50
51 for (int i = 0; i < workerThreadCount; i++) {
52 workers[i] = new Worker(i, queueSize);
53 }
54 for (int i = 0; i < workerThreadCount; i++) {
55 workers[i].start();
56 }
57 LOG.debug("workers started");
58 }
59
60 /**
61 * {@inheritDoc}
62 */
63 @Override
64 public void execute(Event event) {
65 try {
66 int workerIndex = (int) (event.getSession().getId() % workers.length);
67 LOG.debug("executing event {} in worker {}", event, workerIndex);
68 workers[workerIndex].enqueue(event);
69 } catch (InterruptedException e) {
70 // interrupt the world
71 return;
72 }
73 }
74
75 /** thread in charge of gathering events from a queue and running them */
76 private static class Worker extends Thread {
77
78 private static HandlerCaller caller = new HandlerCaller();
79
80 private final BlockingQueue<Event> queue;
81
82 public Worker(int index, int queueSize) {
83 super("IoHandlerWorker " + index);
84 queue = new LinkedBlockingQueue<Event>(queueSize);
85 }
86
87 public void enqueue(Event event) throws InterruptedException {
88 LOG.debug("enqueing event : {}", event);
89 queue.put(event);
90 }
91
92 /**
93 * {@inheritDoc}
94 */
95 @Override
96 public void run() {
97 for (;;) {
98 try {
99
100 Event e = queue.take();
101 LOG.debug("dequeing event {}", e);
102 e.visit(caller);
103
104 } catch (InterruptedException e) {
105 // end this thread
106 return;
107 }
108 }
109 }
110 }
111 }