001/*
002 * jPOS Project [http://jpos.org]
003 * Copyright (C) 2000-2026 jPOS Software SRL
004 *
005 * This program is free software: you can redistribute it and/or modify
006 * it under the terms of the GNU Affero General Public License as
007 * published by the Free Software Foundation, either version 3 of the
008 * License, or (at your option) any later version.
009 *
010 * This program is distributed in the hope that it will be useful,
011 * but WITHOUT ANY WARRANTY; without even the implied warranty of
012 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
013 * GNU Affero General Public License for more details.
014 *
015 * You should have received a copy of the GNU Affero General Public License
016 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
017 */
018
019package org.jpos.util;
020
021import java.util.Timer;
022import java.util.TimerTask;
023import java.util.concurrent.atomic.AtomicLong;
024
025
026/**
027 * WatchDog will issue a warning message 
028 * if not canceled on time
029 */
030@SuppressWarnings("unused")
031public class WatchDog extends TimerTask {
032    String message;
033    String logName;
034    String realm;
035    private static Timer timer = new Timer(true);
036    private static AtomicLong counter = new AtomicLong(0L);
037    /** Number of timer schedules between proactive cancellation purges. */
038    public static long PURGE_INTERVAL = 1000L;
039
040    /**
041     * Schedules a silent watchdog that fires after {@code duration} milliseconds.
042     *
043     * @param duration delay in milliseconds before {@link #run()} fires
044     */
045    public WatchDog (long duration) {
046        timer.schedule(this, duration);
047        if (counter.incrementAndGet() % PURGE_INTERVAL == 0)
048            timer.purge();  // pro-active purge due to excessive number of timertask cancels.
049    }
050    /**
051     * Schedules a watchdog that, if not cancelled in time, logs {@code message} as a warning.
052     *
053     * @param duration delay in milliseconds before {@link #run()} fires
054     * @param message warning message to log when the timer expires
055     */
056    public WatchDog (long duration, String message) {
057        this(duration);
058        this.logName = "Q2";
059        this.realm = "watchdog";
060        this.message = message;
061    }
062    /**
063     * Overrides the logger name used for the warning.
064     *
065     * @param logName logger name (defaults to {@code Q2})
066     */
067    public void setLogName (String logName) {
068        this.logName = logName;
069    }
070    /**
071     * Overrides the realm used for the warning.
072     *
073     * @param realm logger realm (defaults to {@code watchdog})
074     */
075    public void setRealm (String realm) {
076        this.realm = realm;
077    }
078    /** Logs the configured message at warning level when the timer expires. */
079    public void run () {
080        if (message != null)
081            Log.getLog (logName, realm).warn (message);
082    }
083}