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.time.Duration;
022import java.time.Instant;
023import java.util.concurrent.atomic.AtomicReference;
024
025/**
026 * General purpose Chronometer
027 *
028 * Measures execution time (in millis) with support for partial durations.
029 */
030public class Chronometer {
031    private final AtomicReference<Instant> start;
032    private final AtomicReference<Instant> lap;
033
034    /**
035     * Creates a new Chronometer
036     */
037    public Chronometer() {
038        this (Instant.now());
039    }
040
041    /**
042     * Creates a new Chronometer and specify start instant
043     * @param start chronometer start
044     */
045    public Chronometer(Instant start) {
046        this.start = new AtomicReference<>(start);
047        this.lap = new AtomicReference<>(this.start.get());
048    }
049
050    /**
051     * Returns elapsed time since creation or last reset
052     *
053     * @return elapsed time in millis
054     */
055    public long elapsed() {
056        return Duration.between(start.get(), Instant.now()).toMillis();
057    }
058
059    /**
060     * Resets this chronometer.
061     */
062    public void reset() {
063        start.set(Instant.now());
064    }
065
066    /**
067     * Ongoing partial since start or last lap.
068     *
069     * @return ongoing partial in millis.
070     */
071    public long partial() {
072        return Duration.between(lap.get(), Instant.now()).toMillis();
073    }
074
075    /**
076     * Return current partial and resets lap.
077     *
078     * @return partial in millis.
079     */
080    public long lap() {
081        Instant now = Instant.now();
082        long elapsed = Duration.between(lap.get(), now).toMillis();
083        lap.set(now);
084        return elapsed;
085    }
086
087    @Override
088    public String toString() {
089        return "Chronometer{" +
090          "elapsed=" + elapsed() +
091          ", lap=" + (Duration.between(lap.get(), Instant.now()).toMillis()) +
092          '}';
093    }
094}