1/**
2 * Copyright 2012-2013 Florian Schmaus
3 *
4 * All rights reserved. Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *     http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package org.jivesoftware.smackx.ping;
18
19import java.lang.ref.WeakReference;
20import java.util.Set;
21
22import org.jivesoftware.smack.Connection;
23
24class ServerPingTask implements Runnable {
25
26    // This has to be a weak reference because IIRC all threads are roots
27    // for objects and we have a new thread here that should hold a strong
28    // reference to connection so that it can be GCed.
29    private WeakReference<Connection> weakConnection;
30
31    private int delta = 1000; // 1 seconds
32    private int tries = 3; // 3 tries
33
34    protected ServerPingTask(Connection connection) {
35        this.weakConnection = new WeakReference<Connection>(connection);
36    }
37
38    public void run() {
39        Connection connection = weakConnection.get();
40        if (connection == null) {
41            // connection has been collected by GC
42            // which means we can stop the thread by breaking the loop
43            return;
44        }
45        if (connection.isAuthenticated()) {
46            PingManager pingManager = PingManager.getInstanceFor(connection);
47            boolean res = false;
48
49            for (int i = 0; i < tries; i++) {
50                if (i != 0) {
51                    try {
52                        Thread.sleep(delta);
53                    } catch (InterruptedException e) {
54                        // We received an interrupt
55                        // This only happens if we should stop pinging
56                        return;
57                    }
58                }
59                res = pingManager.pingMyServer();
60                // stop when we receive a pong back
61                if (res) {
62                    pingManager.lastSuccessfulPingByTask = System.currentTimeMillis();
63                    break;
64                }
65            }
66            if (!res) {
67                Set<PingFailedListener> pingFailedListeners = pingManager.getPingFailedListeners();
68                for (PingFailedListener l : pingFailedListeners) {
69                    l.pingFailed();
70                }
71            } else {
72                // Ping was successful, wind-up the periodic task again
73                pingManager.maybeSchedulePingServerTask();
74            }
75        }
76    }
77}
78