001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache license, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the license for the specific language governing permissions and 015 * limitations under the license. 016 */ 017package org.apache.logging.log4j.core.config; 018 019import java.io.File; 020import java.util.List; 021import java.util.concurrent.TimeUnit; 022import java.util.concurrent.atomic.AtomicInteger; 023import java.util.concurrent.locks.Lock; 024import java.util.concurrent.locks.ReentrantLock; 025 026/** 027 * Configuration monitor that periodically checks the timestamp of the configuration file and calls the 028 * ConfigurationListeners when an update occurs. 029 */ 030public class FileConfigurationMonitor implements ConfigurationMonitor { 031 032 private static final int MASK = 0x0f; 033 034 static final int MIN_INTERVAL = 5; 035 036 private final File file; 037 038 private volatile long lastModified; 039 040 private final List<ConfigurationListener> listeners; 041 042 private final long intervalNano; 043 044 private volatile long nextCheck; 045 046 private final AtomicInteger counter = new AtomicInteger(0); 047 048 private static final Lock LOCK = new ReentrantLock(); 049 050 private final Reconfigurable reconfigurable; 051 052 /** 053 * Constructor. 054 * @param reconfigurable The Configuration that can be reconfigured. 055 * @param file The File to monitor. 056 * @param listeners The List of ConfigurationListeners to notify upon a change. 057 * @param intervalSeconds The monitor interval in seconds. The minimum interval is 5 seconds. 058 */ 059 public FileConfigurationMonitor(final Reconfigurable reconfigurable, final File file, 060 final List<ConfigurationListener> listeners, 061 final int intervalSeconds) { 062 this.reconfigurable = reconfigurable; 063 this.file = file; 064 this.lastModified = file.lastModified(); 065 this.listeners = listeners; 066 this.intervalNano = TimeUnit.SECONDS.toNanos(Math.max(intervalSeconds, MIN_INTERVAL)); 067 this.nextCheck = System.nanoTime() + this.intervalNano; 068 } 069 070 /** 071 * Called to determine if the configuration has changed. 072 */ 073 @Override 074 public void checkConfiguration() { 075 final long current; 076 if (((counter.incrementAndGet() & MASK) == 0) && ((current = System.nanoTime()) - nextCheck >= 0)) { 077 LOCK.lock(); 078 try { 079 nextCheck = current + intervalNano; 080 final long currentLastModified = file.lastModified(); 081 if (currentLastModified > lastModified) { 082 lastModified = currentLastModified; 083 for (final ConfigurationListener listener : listeners) { 084 final Thread thread = new Thread(new ReconfigurationWorker(listener, reconfigurable)); 085 thread.setDaemon(true); 086 thread.start(); 087 } 088 } 089 } finally { 090 LOCK.unlock(); 091 } 092 } 093 } 094 095 private static class ReconfigurationWorker implements Runnable { 096 097 private final ConfigurationListener listener; 098 private final Reconfigurable reconfigurable; 099 100 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 } 110 111 /* (non-Javadoc) 112 * @see org.apache.logging.log4j.core.config.ReliabilityStrategyFactory#getReliabilityStrategy(org.apache.logging.log4j.core.config.LoggerConfig) 113 */ 114 @Override 115 public ReliabilityStrategy getReliabilityStrategy(LoggerConfig loggerConfig) { 116 return ReliabilityStrategyFactory.getReliabilityStrategy(loggerConfig); 117 } 118}