001package org.apache.commons.jcs.utils.discovery; 002 003/* 004 * Licensed to the Apache Software Foundation (ASF) under one 005 * or more contributor license agreements. See the NOTICE file 006 * distributed with this work for additional information 007 * regarding copyright ownership. The ASF licenses this file 008 * to you under the Apache License, Version 2.0 (the 009 * "License"); you may not use this file except in compliance 010 * with the License. You may obtain a copy of the License at 011 * 012 * http://www.apache.org/licenses/LICENSE-2.0 013 * 014 * Unless required by applicable law or agreed to in writing, 015 * software distributed under the License is distributed on an 016 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 017 * KIND, either express or implied. See the License for the 018 * specific language governing permissions and limitations 019 * under the License. 020 */ 021 022import org.apache.commons.logging.Log; 023import org.apache.commons.logging.LogFactory; 024 025import java.util.HashSet; 026import java.util.Set; 027 028/** 029 * This class periodically check the lastHeardFrom time on the services. 030 * <p> 031 * If they exceed the configurable limit, it removes them from the set. 032 * <p> 033 * @author Aaron Smuts 034 */ 035public class UDPCleanupRunner 036 implements Runnable 037{ 038 /** log instance */ 039 private static final Log log = LogFactory.getLog( UDPCleanupRunner.class ); 040 041 /** UDP discovery service */ 042 private final UDPDiscoveryService discoveryService; 043 044 /** default for max idle time, in seconds */ 045 private static final long DEFAULT_MAX_IDLE_TIME_SECONDS = 180; 046 047 /** The configured max idle time, in seconds */ 048 private final long maxIdleTimeSeconds = DEFAULT_MAX_IDLE_TIME_SECONDS; 049 050 /** 051 * @param service UDPDiscoveryService 052 */ 053 public UDPCleanupRunner( UDPDiscoveryService service ) 054 { 055 this.discoveryService = service; 056 } 057 058 /** 059 * This goes through the list of services and removes those that we haven't heard from in longer 060 * than the max idle time. 061 * <p> 062 * @see java.lang.Runnable#run() 063 */ 064 @Override 065 public void run() 066 { 067 long now = System.currentTimeMillis(); 068 069 // iterate through the set 070 // it is thread safe 071 // http://gee.cs.oswego.edu/dl/classes/EDU/oswego/cs/dl/util/concurrent/CopyOnWriteArraySet. 072 // html 073 // TODO this should get a copy. you can't simply remove from this. 074 // the listeners need to be notified. 075 Set<DiscoveredService> toRemove = new HashSet<DiscoveredService>(); 076 // can't remove via the iterator. must remove directly 077 for (DiscoveredService service : discoveryService.getDiscoveredServices()) 078 { 079 if ( ( now - service.getLastHearFromTime() ) > ( maxIdleTimeSeconds * 1000 ) ) 080 { 081 if ( log.isInfoEnabled() ) 082 { 083 log.info( "Removing service, since we haven't heard from it in " + maxIdleTimeSeconds 084 + " seconds. service = " + service ); 085 } 086 toRemove.add( service ); 087 } 088 } 089 090 // remove the bad ones 091 for (DiscoveredService service : toRemove) 092 { 093 // call this so the listeners get notified 094 discoveryService.removeDiscoveredService( service ); 095 } 096 } 097}