/**
* 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.
*/
package org.apache.hadoop.util;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
/**
* Utility methods for getting the time and computing intervals.
*
* It has the same behavior as {{@link Time}}, with the exception that its
* functions can be overridden for dependency injection purposes.
*/
@InterfaceAudience.Private
@InterfaceStability.Unstable
public class Timer {
/**
* 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 long now() {
return Time.now();
}
/**
* 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 long monotonicNow() { return Time.monotonicNow(); }
}