Logback: the reliable, generic, fast and flexible logging framework.
Copyright (C) 1999-2015, QOS.ch. All rights reserved.
This program and the accompanying materials are dual-licensed under
either the terms of the Eclipse Public License v1.0 as published by
the Eclipse Foundation
  or (per the licensee's choosing)
under the terms of the GNU Lesser General Public License version 2.1
as published by the Free Software Foundation.
/**
 * Logback: the reliable, generic, fast and flexible logging framework.
 * Copyright (C) 1999-2015, QOS.ch. All rights reserved.
 *
 * This program and the accompanying materials are dual-licensed under
 * either the terms of the Eclipse Public License v1.0 as published by
 * the Eclipse Foundation
 *
 *   or (per the licensee's choosing)
 *
 * under the terms of the GNU Lesser General Public License version 2.1
 * as published by the Free Software Foundation.
 */
package ch.qos.logback.core.recovery;

public class RecoveryCoordinator {

    public final static long BACKOFF_COEFFICIENT_MIN = 20;
    public final static long BACKOFF_MULTIPLIER = 4;
    static long BACKOFF_COEFFICIENT_MAX = 327680; // BACKOFF_COEFFICIENT_MIN * 4^7

    private long backOffCoefficient = BACKOFF_COEFFICIENT_MIN;

    private static long UNSET = -1;
    // tests can set the time directly independently of system clock
    private long currentTime = UNSET;
    private long next;

    public RecoveryCoordinator() {
        next = getCurrentTime() + getBackoffCoefficient();
    }

    public RecoveryCoordinator(long currentTime) {
        this.currentTime = currentTime;
        next = getCurrentTime() + getBackoffCoefficient();
    }

    public boolean isTooSoon() {
        long now = getCurrentTime();
        if (now > next) {
            next = now + getBackoffCoefficient();
            return false;
        } else {
            return true;
        }
    }

    void setCurrentTime(long forcedTime) {
        currentTime = forcedTime;
    }

    private long getCurrentTime() {
        if (currentTime != UNSET) {
            return currentTime;
        }
        return System.currentTimeMillis();
    }

    private long getBackoffCoefficient() {
        long currentCoeff = backOffCoefficient;
        if (backOffCoefficient < BACKOFF_COEFFICIENT_MAX) {
            backOffCoefficient *= BACKOFF_MULTIPLIER;
        }
        return currentCoeff;
    }
}