org.apache.solr.common.util

Class TimeSource

java.lang.Object

org.apache.solr.common.util.TimeSource

Direct Known Subclasses:

TimeSource.CurrentTimeSource, TimeSource.NanoTimeSource, TimeSource.SimTimeSource

public abstract class TimeSource
extends Object

Source of time.

NOTE: depending on implementation returned values may not be related in any way to the current Epoch or calendar time, and they may even be negative - but the API guarantees that they are always monotonically increasing.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	TimeSource.CurrentTimeSource Implementation that uses System.currentTimeMillis().
static class	TimeSource.NanoTimeSource Implementation that uses System.nanoTime().
static class	TimeSource.SimTimeSource Implementation that uses NANO_TIME accelerated by a double multiplier.

Field Summary

Fields

Modifier and Type	Field and Description
static TimeSource	CURRENT_TIME This instance uses TimeSource.CurrentTimeSource for generating timestamps.
static TimeSource	NANO_TIME This instance uses TimeSource.NanoTimeSource for generating timestamps.

Constructor Summary

Constructors

Constructor and Description
TimeSource()

Method Summary

Modifier and Type	Method and Description
abstract long	convertDelay(TimeUnit fromUnit, long value, TimeUnit toUnit) This method allows using TimeSource with APIs that require providing just plain time intervals, eg.
static TimeSource	get(String type) Obtain an instance of time source.
abstract long	getEpochTimeNs() Return Epoch time.
abstract long[]	getTimeAndEpochNs() Return both the source's time value and the corresponding epoch time value.
abstract long	getTimeNs() Return a time value, in nanosecond units.
abstract void	sleep(long ms) Sleep according to this source's notion of time.
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

CURRENT_TIME

public static final TimeSource CURRENT_TIME

This instance uses TimeSource.CurrentTimeSource for generating timestamps.

NANO_TIME

public static final TimeSource NANO_TIME

This instance uses TimeSource.NanoTimeSource for generating timestamps.

Constructor Detail

TimeSource

public TimeSource()

Method Detail

get

public static TimeSource get(String type)

Obtain an instance of time source.

Parameters:

type - supported types: currentTime, nanoTime and accelerated time with a double factor in the form of simTime:FACTOR, eg. simTime:2.5

Returns:

one of the supported types

getTimeNs

public abstract long getTimeNs()

Return a time value, in nanosecond units. Depending on implementation this value may or may not be related to Epoch time.

getEpochTimeNs

public abstract long getEpochTimeNs()

Return Epoch time. Implementations that are not natively based on epoch time may return values that are consistently off by a (small) fixed number of milliseconds from the actual epoch time.

getTimeAndEpochNs

public abstract long[] getTimeAndEpochNs()

Return both the source's time value and the corresponding epoch time value. This method ensures that epoch time calculations use the same internal value of time as that reported by getTimeNs().

Returns:

an array where the first element is getTimeNs() and the second element is getEpochTimeNs().

sleep

public abstract void sleep(long ms)
                    throws InterruptedException

Sleep according to this source's notion of time. Eg. accelerated time source such as TimeSource.SimTimeSource will sleep proportionally shorter, according to its multiplier.

Parameters:

ms - number of milliseconds to sleep

Throws:

InterruptedException - when the current thread is interrupted

convertDelay

public abstract long convertDelay(TimeUnit fromUnit,
                                  long value,
                                  TimeUnit toUnit)

This method allows using TimeSource with APIs that require providing just plain time intervals, eg. Object.wait(long). Values returned by this method are adjusted according to the time source's notion of time - eg. accelerated time source provided by TimeSource.SimTimeSource will return intervals that are proportionally shortened by the multiplier.

NOTE: converting small values may significantly affect precision of the returned values due to rounding, especially for accelerated time source, so care should be taken to use time units that result in relatively large values. For example, converting a value of 1 expressed in seconds would result in less precision than converting a value of 1000 expressed in milliseconds.

Parameters:

fromUnit - source unit

value - original value

toUnit - target unit

Returns:

converted value, possibly scaled by the source's notion of accelerated time (see TimeSource.SimTimeSource)

toString

public String toString()

Overrides:

toString in class Object