Package org.apache.hadoop.util

Class Timer

java.lang.Object

org.apache.hadoop.util.Timer

@Private
@Unstable
public class Timer
extends Object

Utility methods for getting the time and computing intervals. It has the same behavior as {Time}, with the exception that its functions can be overridden for dependency injection purposes.

Constructor Summary

Constructors

Constructor	Description
Timer()

Method Summary

Modifier and Type	Method	Description
long	monotonicNow()	Current time from some arbitrary time base in the past, counting in milliseconds, and not affected by settimeofday or similar system clock changes.
long	monotonicNowNanos()	Same as monotonicNow() but returns its result in nanoseconds.
long	now()	Current system time.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

Timer

public Timer()

Method Details

now

public long now()

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.

Returns:

current time in msec.

monotonicNow

public long monotonicNow()

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.

Returns:

a monotonic clock that counts in milliseconds.

monotonicNowNanos

public long monotonicNowNanos()

Same as monotonicNow() but returns its result in nanoseconds. Note that this is subject to the same resolution constraints as System.nanoTime().

Returns:

a monotonic clock that counts in nanoseconds.