1 package org.apache.commons.jcs.utils.discovery;
2
3 /*
4 * Licensed to the Apache Software Foundation (ASF) under one
5 * or more contributor license agreements. See the NOTICE file
6 * distributed with this work for additional information
7 * regarding copyright ownership. The ASF licenses this file
8 * to you under the Apache License, Version 2.0 (the
9 * "License"); you may not use this file except in compliance
10 * with the License. You may obtain a copy of the License at
11 *
12 * http://www.apache.org/licenses/LICENSE-2.0
13 *
14 * Unless required by applicable law or agreed to in writing,
15 * software distributed under the License is distributed on an
16 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17 * KIND, either express or implied. See the License for the
18 * specific language governing permissions and limitations
19 * under the License.
20 */
21
22 import org.apache.commons.logging.Log;
23 import org.apache.commons.logging.LogFactory;
24
25 import java.util.HashSet;
26 import java.util.Set;
27
28 /**
29 * This class periodically check the lastHeardFrom time on the services.
30 * <p>
31 * If they exceed the configurable limit, it removes them from the set.
32 * <p>
33 * @author Aaron Smuts
34 */
35 public class UDPCleanupRunner
36 implements Runnable
37 {
38 /** log instance */
39 private static final Log log = LogFactory.getLog( UDPCleanupRunner.class );
40
41 /** UDP discovery service */
42 private final UDPDiscoveryService discoveryService;
43
44 /** default for max idle time, in seconds */
45 private static final long DEFAULT_MAX_IDLE_TIME_SECONDS = 180;
46
47 /** The configured max idle time, in seconds */
48 private final long maxIdleTimeSeconds = DEFAULT_MAX_IDLE_TIME_SECONDS;
49
50 /**
51 * @param service UDPDiscoveryService
52 */
53 public UDPCleanupRunner( UDPDiscoveryService service )
54 {
55 this.discoveryService = service;
56 }
57
58 /**
59 * This goes through the list of services and removes those that we haven't heard from in longer
60 * than the max idle time.
61 * <p>
62 * @see java.lang.Runnable#run()
63 */
64 @Override
65 public void run()
66 {
67 long now = System.currentTimeMillis();
68
69 // iterate through the set
70 // it is thread safe
71 // http://gee.cs.oswego.edu/dl/classes/EDU/oswego/cs/dl/util/concurrent/CopyOnWriteArraySet.
72 // html
73 // TODO this should get a copy. you can't simply remove from this.
74 // the listeners need to be notified.
75 Set<DiscoveredService> toRemove = new HashSet<DiscoveredService>();
76 // can't remove via the iterator. must remove directly
77 for (DiscoveredService service : discoveryService.getDiscoveredServices())
78 {
79 if ( ( now - service.getLastHearFromTime() ) > ( maxIdleTimeSeconds * 1000 ) )
80 {
81 if ( log.isInfoEnabled() )
82 {
83 log.info( "Removing service, since we haven't heard from it in " + maxIdleTimeSeconds
84 + " seconds. service = " + service );
85 }
86 toRemove.add( service );
87 }
88 }
89
90 // remove the bad ones
91 for (DiscoveredService service : toRemove)
92 {
93 // call this so the listeners get notified
94 discoveryService.removeDiscoveredService( service );
95 }
96 }
97 }