/**
    * Logback: the reliable, generic, fast and flexible logging framework.
    * Copyright (C) 1999-2011, 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 = 100;
    static long BACKOFF_COEFFICIENT_MAX = 409600;  // BACKOFF_COEFFICIENT_MIN * 4^6
    
    private long backOffCoefficient = BACKOFF_COEFFICIENT_MIN;
    
    private static long UNSET = -1;
    private long currentTime = UNSET;
    long next = System.currentTimeMillis()+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*=4;
      }
      return currentCoeff;
    }
  }