com.tencent.angel.utils.Time Maven / Gradle / Ivy
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/*
* Tencent is pleased to support the open source community by making Angel available.
*
* Copyright (C) 2017-2018 THL A29 Limited, a Tencent company. All rights reserved.
*
* Licensed 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
*
* https://opensource.org/licenses/Apache-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.
*
*/
package com.tencent.angel.utils;
/**
* Utility methods for getting the time and computing intervals.
*/
public final class Time {
/**
* Current system time. Do not use this to calculate a duration or interval to sleep, because it
* will be broken by settimeofday. Instead, use monotonicNow.
*
* @return current time in msec.
*/
public static long now() {
return System.currentTimeMillis();
}
/**
* Current time from some arbitrary time base in the past, counting in milliseconds, and not
* affected by settimeofday or similar system clock changes. This is appropriate to use when
* computing how much longer to wait for an interval to expire.
*
* @return a monotonic clock that counts in milliseconds.
*/
public static long monotonicNow() {
final long NANOSECONDS_PER_MILLISECOND = 1000000;
return System.nanoTime() / NANOSECONDS_PER_MILLISECOND;
}
}