/**
    * 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;
      }
  }