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 org.apache.logging.log4j.Logger;
020import org.apache.logging.log4j.core.AbstractLifeCycle;
021import org.apache.logging.log4j.core.config.Configuration;
022import org.apache.logging.log4j.core.config.ConfigurationScheduler;
023import org.apache.logging.log4j.status.StatusLogger;
024
025import java.io.File;
026import java.util.Map;
027import java.util.concurrent.ConcurrentHashMap;
028import java.util.concurrent.ConcurrentMap;
029import java.util.concurrent.ScheduledExecutorService;
030import java.util.concurrent.ScheduledFuture;
031import java.util.concurrent.TimeUnit;
032
033/**
034 * Manages FileWatchers.
035 */
036public class WatchManager extends AbstractLifeCycle {
037
038    private static final long serialVersionUID = 8998356999926962686L;
039    private static Logger logger = StatusLogger.getLogger();
040    private final ConcurrentMap<File, FileMonitor> watchers = new ConcurrentHashMap<>();
041    private int intervalSeconds = 0;
042    private ScheduledFuture<?> future;
043    private ConfigurationScheduler scheduler;
044
045    public WatchManager(ConfigurationScheduler scheduler) {
046        this.scheduler = scheduler;
047    }
048
049    public void setIntervalSeconds(int intervalSeconds) {
050        if (!isStarted()) {
051            if (this.intervalSeconds > 0 && intervalSeconds == 0) {
052                scheduler.decrementScheduledItems();
053            } else if (this.intervalSeconds == 0 && intervalSeconds > 0) {
054                scheduler.incrementScheduledItems();
055            }
056            this.intervalSeconds = intervalSeconds;
057        }
058    }
059
060    public int getIntervalSeconds() {
061        return this.intervalSeconds;
062    }
063
064    @Override
065    public void start() {
066        super.start();
067        if (intervalSeconds > 0) {
068            future = scheduler.scheduleWithFixedDelay(new WatchWorker(), intervalSeconds, intervalSeconds,
069                    TimeUnit.SECONDS);
070        }
071    }
072
073    @Override
074    public void stop() {
075        future.cancel(true);
076        super.stop();
077    }
078
079    public void watchFile(File file, FileWatcher watcher) {
080        watchers.put(file, new FileMonitor(file.lastModified(), watcher));
081
082    }
083
084    private class WatchWorker implements Runnable {
085
086        @Override
087        public void run() {
088            for (Map.Entry<File, FileMonitor> entry : watchers.entrySet()) {
089                File file = entry.getKey();
090                FileMonitor fileMonitor = entry.getValue();
091                long lastModfied = file.lastModified();
092                if (lastModfied > fileMonitor.lastModified) {
093                    logger.info("File {} was modified", file.toString());
094                    fileMonitor.lastModified = lastModfied;
095                    fileMonitor.fileWatcher.fileModified(file);
096                }
097            }
098        }
099    }
100
101    private class FileMonitor {
102        private final FileWatcher fileWatcher;
103        private long lastModified;
104
105        public FileMonitor(long lastModified, FileWatcher fileWatcher) {
106            this.fileWatcher = fileWatcher;
107            this.lastModified = lastModified;
108        }
109    }
110}