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.HashMap;
021import java.util.Map;
022import java.util.concurrent.ConcurrentHashMap;
023import java.util.concurrent.ConcurrentMap;
024import java.util.concurrent.ScheduledFuture;
025import java.util.concurrent.TimeUnit;
026
027import org.apache.logging.log4j.Logger;
028import org.apache.logging.log4j.core.AbstractLifeCycle;
029import org.apache.logging.log4j.core.config.ConfigurationScheduler;
030import org.apache.logging.log4j.status.StatusLogger;
031
032/**
033 * Manages FileWatchers.
034 */
035public class WatchManager extends AbstractLifeCycle {
036
037    private static Logger logger = StatusLogger.getLogger();
038    private final ConcurrentMap<File, FileMonitor> watchers = new ConcurrentHashMap<>();
039    private int intervalSeconds = 0;
040    private ScheduledFuture<?> future;
041    private final ConfigurationScheduler scheduler;
042
043    public WatchManager(ConfigurationScheduler scheduler) {
044        this.scheduler = scheduler;
045    }
046
047    public void setIntervalSeconds(int intervalSeconds) {
048        if (!isStarted()) {
049            if (this.intervalSeconds > 0 && intervalSeconds == 0) {
050                scheduler.decrementScheduledItems();
051            } else if (this.intervalSeconds == 0 && intervalSeconds > 0) {
052                scheduler.incrementScheduledItems();
053            }
054            this.intervalSeconds = intervalSeconds;
055        }
056    }
057
058    public int getIntervalSeconds() {
059        return this.intervalSeconds;
060    }
061
062    @Override
063    public void start() {
064        super.start();
065        if (intervalSeconds > 0) {
066            future = scheduler.scheduleWithFixedDelay(new WatchWorker(), intervalSeconds, intervalSeconds,
067                    TimeUnit.SECONDS);
068        }
069    }
070
071    @Override
072    public void stop() {
073        future.cancel(true);
074        super.stop();
075    }
076
077    public void watchFile(File file, FileWatcher watcher) {
078        watchers.put(file, new FileMonitor(file.lastModified(), watcher));
079
080    }
081
082    public Map<File, FileWatcher> getWatchers() {
083        Map<File, FileWatcher> map = new HashMap<>();
084        for (Map.Entry<File, FileMonitor> entry : watchers.entrySet()) {
085            map.put(entry.getKey(), entry.getValue().fileWatcher);
086        }
087        return map;
088    }
089
090    private class WatchWorker implements Runnable {
091
092        @Override
093        public void run() {
094            for (Map.Entry<File, FileMonitor> entry : watchers.entrySet()) {
095                File file = entry.getKey();
096                FileMonitor fileMonitor = entry.getValue();
097                long lastModfied = file.lastModified();
098                if (fileModified(fileMonitor, lastModfied)) {
099                    logger.info("File {} was modified", file.toString());
100                    fileMonitor.lastModified = lastModfied;
101                    fileMonitor.fileWatcher.fileModified(file);
102                }
103            }
104        }
105
106        private boolean fileModified(FileMonitor fileMonitor, long lastModfied) {
107            return lastModfied != fileMonitor.lastModified;
108        }
109    }
110
111    private class FileMonitor {
112        private final FileWatcher fileWatcher;
113        private long lastModified;
114
115        public FileMonitor(long lastModified, FileWatcher fileWatcher) {
116            this.fileWatcher = fileWatcher;
117            this.lastModified = lastModified;
118        }
119    }
120}