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17 package org.apache.logging.log4j.core.config;
18
19 import java.io.File;
20 import java.util.List;
21 import java.util.concurrent.TimeUnit;
22 import java.util.concurrent.atomic.AtomicInteger;
23 import java.util.concurrent.locks.Lock;
24 import java.util.concurrent.locks.ReentrantLock;
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29
30 public class FileConfigurationMonitor implements ConfigurationMonitor {
31
32 private static final int MASK = 0x0f;
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34 static final int MIN_INTERVAL = 5;
35
36 private final File file;
37
38 private volatile long lastModified;
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40 private final List<ConfigurationListener> listeners;
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42 private final long intervalNano;
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44 private volatile long nextCheck;
45
46 private final AtomicInteger counter = new AtomicInteger(0);
47
48 private static final Lock LOCK = new ReentrantLock();
49
50 private final Reconfigurable reconfigurable;
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59 public FileConfigurationMonitor(final Reconfigurable reconfigurable, final File file,
60 final List<ConfigurationListener> listeners,
61 final int intervalSeconds) {
62 this.reconfigurable = reconfigurable;
63 this.file = file;
64 this.lastModified = file.lastModified();
65 this.listeners = listeners;
66 this.intervalNano = TimeUnit.SECONDS.toNanos(Math.max(intervalSeconds, MIN_INTERVAL));
67 this.nextCheck = System.nanoTime() + this.intervalNano;
68 }
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72
73 @Override
74 public void checkConfiguration() {
75 final long current;
76 if (((counter.incrementAndGet() & MASK) == 0) && ((current = System.nanoTime()) - nextCheck >= 0)) {
77 LOCK.lock();
78 try {
79 nextCheck = current + intervalNano;
80 final long currentLastModified = file.lastModified();
81 if (currentLastModified > lastModified) {
82 lastModified = currentLastModified;
83 for (final ConfigurationListener listener : listeners) {
84 final Thread thread = new Thread(new ReconfigurationWorker(listener, reconfigurable));
85 thread.setDaemon(true);
86 thread.start();
87 }
88 }
89 } finally {
90 LOCK.unlock();
91 }
92 }
93 }
94
95 private static class ReconfigurationWorker implements Runnable {
96
97 private final ConfigurationListener listener;
98 private final Reconfigurable reconfigurable;
99
100 public ReconfigurationWorker(final ConfigurationListener listener, final Reconfigurable reconfigurable) {
101 this.listener = listener;
102 this.reconfigurable = reconfigurable;
103 }
104
105 @Override
106 public void run() {
107 listener.onChange(reconfigurable);
108 }
109 }
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114 @Override
115 public ReliabilityStrategy getReliabilityStrategy(LoggerConfig loggerConfig) {
116 return ReliabilityStrategyFactory.getReliabilityStrategy(loggerConfig);
117 }
118 }