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;
021
022import org.apache.logging.log4j.core.util.AbstractWatcher;
023import org.apache.logging.log4j.core.util.FileWatcher;
024import org.apache.logging.log4j.core.util.Source;
025import org.apache.logging.log4j.core.util.Watcher;
026
027/**
028 * Watcher for configuration files. Causes a reconfiguration when a file changes.
029 */
030public class ConfigurationFileWatcher extends AbstractWatcher implements FileWatcher {
031
032    private File file;
033    private long lastModifiedMillis;
034
035    public ConfigurationFileWatcher(final Configuration configuration, final Reconfigurable reconfigurable,
036            final List<ConfigurationListener> configurationListeners, long lastModifiedMillis) {
037        super(configuration, reconfigurable, configurationListeners);
038        this.lastModifiedMillis = lastModifiedMillis;
039    }
040
041    public long getLastModified() {
042        return file != null ? file.lastModified() : 0;
043    }
044
045    @Override
046    public void fileModified(final File file) {
047        lastModifiedMillis = file.lastModified();
048    }
049
050    @Override
051    public void watching(Source source) {
052        file = source.getFile();
053        lastModifiedMillis = file.lastModified();
054        super.watching(source);
055    }
056
057    @Override
058    public boolean isModified() {
059        return lastModifiedMillis != file.lastModified();
060    }
061
062    @Override
063    public Watcher newWatcher(final Reconfigurable reconfigurable, final List<ConfigurationListener> listeners,
064        long lastModifiedMillis) {
065        ConfigurationFileWatcher watcher = new ConfigurationFileWatcher(getConfiguration(), reconfigurable, listeners,
066            lastModifiedMillis);
067        if (getSource() != null) {
068            watcher.watching(getSource());
069        }
070        return watcher;
071    }
072}