001package org.apache.commons.jcs.auxiliary.lateral; 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 java.util.Map; 023import java.util.concurrent.ConcurrentHashMap; 024 025import org.apache.commons.jcs.auxiliary.AbstractAuxiliaryCacheMonitor; 026import org.apache.commons.jcs.auxiliary.lateral.socket.tcp.LateralTCPCacheFactory; 027import org.apache.commons.jcs.auxiliary.lateral.socket.tcp.behavior.ITCPLateralCacheAttributes; 028import org.apache.commons.jcs.engine.CacheStatus; 029import org.apache.commons.jcs.engine.ZombieCacheServiceNonLocal; 030import org.apache.commons.jcs.engine.behavior.ICacheServiceNonLocal; 031 032/** 033 * Used to monitor and repair any failed connection for the lateral cache service. By default the 034 * monitor operates in a failure driven mode. That is, it goes into a wait state until there is an 035 * error. Upon the notification of a connection error, the monitor changes to operate in a time 036 * driven mode. That is, it attempts to recover the connections on a periodic basis. When all failed 037 * connections are restored, it changes back to the failure driven mode. 038 */ 039public class LateralCacheMonitor extends AbstractAuxiliaryCacheMonitor 040{ 041 /** 042 * Map of caches to monitor 043 */ 044 private ConcurrentHashMap<String, LateralCacheNoWait<?, ?>> caches; 045 046 /** 047 * Reference to the factory 048 */ 049 private LateralTCPCacheFactory factory; 050 051 /** 052 * Allows close classes, ie testers to set the idle period to something testable. 053 * <p> 054 * @param idlePeriod 055 */ 056 protected static void forceShortIdlePeriod( long idlePeriod ) 057 { 058 LateralCacheMonitor.idlePeriod = idlePeriod; 059 } 060 061 /** 062 * Constructor for the LateralCacheMonitor object 063 * <p> 064 * It's the clients responsibility to decide how many of these there will be. 065 * 066 * @param factory a reference to the factory that manages the service instances 067 */ 068 public LateralCacheMonitor(LateralTCPCacheFactory factory) 069 { 070 super("JCS-LateralCacheMonitor"); 071 this.factory = factory; 072 this.caches = new ConcurrentHashMap<String, LateralCacheNoWait<?,?>>(); 073 setIdlePeriod(20000L); 074 } 075 076 /** 077 * Add a cache to be monitored 078 * 079 * @param cache the cache 080 */ 081 public void addCache(LateralCacheNoWait<?, ?> cache) 082 { 083 this.caches.put(cache.getCacheName(), cache); 084 085 // if not yet started, go ahead 086 if (this.getState() == Thread.State.NEW) 087 { 088 this.start(); 089 } 090 } 091 092 /** 093 * Clean up all resources before shutdown 094 */ 095 @Override 096 public void dispose() 097 { 098 this.caches.clear(); 099 } 100 101 /** 102 * Main processing method for the LateralCacheMonitor object 103 */ 104 @Override 105 public void doWork() 106 { 107 // Monitor each cache instance one after the other. 108 log.info( "Number of caches to monitor = " + caches.size() ); 109 //for 110 for (Map.Entry<String, LateralCacheNoWait<?, ?>> entry : caches.entrySet()) 111 { 112 String cacheName = entry.getKey(); 113 114 @SuppressWarnings("unchecked") // Downcast to match service 115 LateralCacheNoWait<Object, Object> c = (LateralCacheNoWait<Object, Object>) entry.getValue(); 116 if ( c.getStatus() == CacheStatus.ERROR ) 117 { 118 log.info( "Found LateralCacheNoWait in error, " + cacheName ); 119 120 ITCPLateralCacheAttributes lca = (ITCPLateralCacheAttributes)c.getAuxiliaryCacheAttributes(); 121 122 // Get service instance 123 ICacheServiceNonLocal<Object, Object> cacheService = factory.getCSNLInstance(lca); 124 125 // If we can't fix them, just skip and re-try in the 126 // next round. 127 if (cacheService instanceof ZombieCacheServiceNonLocal) 128 { 129 continue; 130 } 131 132 c.fixCache(cacheService); 133 } 134 } 135 } 136}