| /** |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| #include "Backoff.h" |
| #include <boost/random/uniform_int_distribution.hpp> |
| |
| namespace pulsar { |
| |
| Backoff::Backoff(const TimeDuration& initial, const TimeDuration& max, const TimeDuration& mandatoryStop) |
| : initial_(initial), |
| max_(max), |
| next_(initial), |
| mandatoryStopMade_(false), |
| mandatoryStop_(mandatoryStop), |
| rng_(time(NULL)) {} |
| |
| TimeDuration Backoff::next() { |
| TimeDuration current = next_; |
| next_ = std::min(next_ * 2, max_); |
| |
| // Check for mandatory stop |
| if (!mandatoryStopMade_) { |
| const boost::posix_time::ptime& now = boost::posix_time::microsec_clock::universal_time(); |
| TimeDuration timeElapsedSinceFirstBackoff = boost::posix_time::milliseconds(0); |
| if (initial_ == current) { |
| firstBackoffTime_ = now; |
| } else { |
| timeElapsedSinceFirstBackoff = now - firstBackoffTime_; |
| } |
| if (timeElapsedSinceFirstBackoff + current > mandatoryStop_) { |
| current = std::max(initial_, mandatoryStop_ - timeElapsedSinceFirstBackoff); |
| mandatoryStopMade_ = true; |
| } |
| } |
| // Add Randomness |
| boost::random::uniform_int_distribution<int> dist; |
| int randomNumber = dist(rng_); |
| |
| current = current - (current * (randomNumber % 10) / 100); |
| return std::max(initial_, current); |
| } |
| |
| void Backoff::reset() { |
| next_ = initial_; |
| mandatoryStopMade_ = false; |
| } |
| |
| } // namespace pulsar |