/* * Copyright (c) 2015-present, Facebook, Inc. * All rights reserved. * * This source code is licensed under the BSD-style license found in the * LICENSE file in the root directory of this source tree. An additional grant * of patent rights can be found in the PATENTS file in the same directory. */ package com.facebook.common.time; import com.facebook.common.internal.DoNotStrip; /** * A clock that is guaranteed not to go backward. */ public interface MonotonicClock { /** * Produce a timestamp. Values returned from this method may only be compared to other values * returned from this clock in this process. They have no meaning outside of this process * and should not be written to disk. * * The difference between two timestamps is an interval, in milliseconds. * * @return A timestamp for the current time, in ms. */ @DoNotStrip long now(); }