1 package org.apache.commons.jcs.auxiliary;
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22 import java.util.concurrent.atomic.AtomicBoolean;
23 import java.util.concurrent.locks.Condition;
24 import java.util.concurrent.locks.Lock;
25 import java.util.concurrent.locks.ReentrantLock;
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27 import org.apache.commons.logging.Log;
28 import org.apache.commons.logging.LogFactory;
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37 public abstract class AbstractAuxiliaryCacheMonitor extends Thread
38 {
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40 protected final Log log = LogFactory.getLog( this.getClass() );
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43 protected static long idlePeriod = 20 * 1000;
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48 protected AtomicBoolean allright = new AtomicBoolean(true);
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53 private AtomicBoolean shutdown = new AtomicBoolean(false);
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56 private Lock lock = new ReentrantLock();
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59 private Condition trigger = lock.newCondition();
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66 public AbstractAuxiliaryCacheMonitor(String name)
67 {
68 super(name);
69 }
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76 public static void setIdlePeriod( long idlePeriod )
77 {
78 if ( idlePeriod > AbstractAuxiliaryCacheMonitor.idlePeriod )
79 {
80 AbstractAuxiliaryCacheMonitor.idlePeriod = idlePeriod;
81 }
82 }
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87 public void notifyError()
88 {
89 if (allright.compareAndSet(true, false))
90 {
91 signalTrigger();
92 }
93 }
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98 public void notifyShutdown()
99 {
100 if (shutdown.compareAndSet(false, true))
101 {
102 signalTrigger();
103 }
104 }
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107 private void signalTrigger()
108 {
109 try
110 {
111 lock.lock();
112 trigger.signal();
113 }
114 finally
115 {
116 lock.unlock();
117 }
118 }
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123 protected abstract void dispose();
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128 protected abstract void doWork();
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133 @Override
134 public void run()
135 {
136 do
137 {
138 if ( log.isDebugEnabled() )
139 {
140 if ( allright.get() )
141 {
142 log.debug( "ERROR DRIVEN MODE: allright = true, cache monitor will wait for an error." );
143 }
144 else
145 {
146 log.debug( "ERROR DRIVEN MODE: allright = false cache monitor running." );
147 }
148 }
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150 if ( allright.get() )
151 {
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153 try
154 {
155 lock.lock();
156 trigger.await();
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158 }
159 catch ( InterruptedException ignore )
160 {
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162 }
163 finally
164 {
165 lock.unlock();
166 }
167 }
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170 if ( shutdown.get() )
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172 log.info( "Shutting down cache monitor" );
173 dispose();
174 return;
175 }
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179 allright.set(true);
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181 if ( log.isDebugEnabled() )
182 {
183 log.debug( "Cache monitor running." );
184 }
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186 doWork();
187
188 try
189 {
190
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192 if ( log.isDebugEnabled() )
193 {
194 log.debug( "Cache monitor sleeping for " + idlePeriod + " between runs." );
195 }
196
197 Thread.sleep( idlePeriod );
198 }
199 catch ( InterruptedException ex )
200 {
201
202 }
203 }
204 while ( true );
205 }
206 }