001/**
002 * Logback: the reliable, generic, fast and flexible logging framework.
003 * Copyright (C) 1999-2015, QOS.ch. All rights reserved.
004 *
005 * This program and the accompanying materials are dual-licensed under
006 * either the terms of the Eclipse Public License v1.0 as published by
007 * the Eclipse Foundation
008 *
009 *   or (per the licensee's choosing)
010 *
011 * under the terms of the GNU Lesser General Public License version 2.1
012 * as published by the Free Software Foundation.
013 */
014package ch.qos.logback.core.recovery;
015
016public class RecoveryCoordinator {
017
018    public final static long BACKOFF_COEFFICIENT_MIN = 20;
019    public final static long BACKOFF_MULTIPLIER = 4;
020    static long BACKOFF_COEFFICIENT_MAX = 327680; // BACKOFF_COEFFICIENT_MIN * 4^7
021
022    private long backOffCoefficient = BACKOFF_COEFFICIENT_MIN;
023
024    private static long UNSET = -1;
025    // tests can set the time directly independently of system clock
026    private long currentTime = UNSET;
027    private long next;
028
029    public RecoveryCoordinator() {
030        next = getCurrentTime() + getBackoffCoefficient();
031    }
032
033    public RecoveryCoordinator(long currentTime) {
034        this.currentTime = currentTime;
035        next = getCurrentTime() + getBackoffCoefficient();
036    }
037
038    public boolean isTooSoon() {
039        long now = getCurrentTime();
040        if (now > next) {
041            next = now + getBackoffCoefficient();
042            return false;
043        } else {
044            return true;
045        }
046    }
047
048    void setCurrentTime(long forcedTime) {
049        currentTime = forcedTime;
050    }
051
052    private long getCurrentTime() {
053        if (currentTime != UNSET) {
054            return currentTime;
055        }
056        return System.currentTimeMillis();
057    }
058
059    private long getBackoffCoefficient() {
060        long currentCoeff = backOffCoefficient;
061        if (backOffCoefficient < BACKOFF_COEFFICIENT_MAX) {
062            backOffCoefficient *= BACKOFF_MULTIPLIER;
063        }
064        return currentCoeff;
065    }
066}