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.util; 018 019import java.io.File; 020import java.util.List; 021 022import org.apache.logging.log4j.core.config.Configuration; 023import org.apache.logging.log4j.core.config.ConfigurationListener; 024import org.apache.logging.log4j.core.config.Reconfigurable; 025 026/** 027 * Watcher for configuration files. Causes a reconfiguration when a file changes. 028 */ 029public abstract class AbstractWatcher implements Watcher { 030 031 private final Reconfigurable reconfigurable; 032 private final List<ConfigurationListener> configurationListeners; 033 private final Log4jThreadFactory threadFactory; 034 private final Configuration configuration; 035 private Source source; 036 037 public AbstractWatcher(final Configuration configuration, final Reconfigurable reconfigurable, 038 final List<ConfigurationListener> configurationListeners) { 039 this.configuration = configuration; 040 this.reconfigurable = reconfigurable; 041 this.configurationListeners = configurationListeners; 042 this.threadFactory = configurationListeners != null ? 043 Log4jThreadFactory.createDaemonThreadFactory("ConfiguratonFileWatcher") : null; 044 } 045 046 @Override 047 public List<ConfigurationListener> getListeners() { 048 return configurationListeners; 049 } 050 051 @Override 052 public void modified() { 053 for (final ConfigurationListener configurationListener : configurationListeners) { 054 final Thread thread = threadFactory.newThread(new ReconfigurationRunnable(configurationListener, reconfigurable)); 055 thread.start(); 056 } 057 } 058 059 public Configuration getConfiguration() { 060 return configuration; 061 } 062 063 public abstract long getLastModified(); 064 065 public abstract boolean isModified(); 066 067 @Override 068 public void watching(Source source) { 069 this.source = source; 070 } 071 072 @Override 073 public Source getSource() { 074 return source; 075 } 076 077 /** 078 * Helper class for triggering a reconfiguration in a background thread. 079 */ 080 public static class ReconfigurationRunnable implements Runnable { 081 082 private final ConfigurationListener configurationListener; 083 private final Reconfigurable reconfigurable; 084 085 public ReconfigurationRunnable(final ConfigurationListener configurationListener, final Reconfigurable reconfigurable) { 086 this.configurationListener = configurationListener; 087 this.reconfigurable = reconfigurable; 088 } 089 090 @Override 091 public void run() { 092 configurationListener.onChange(reconfigurable); 093 } 094 } 095}