SystemClock (Time4J-Core 4.4 API)

java.lang.Object
- net.time4j.SystemClock

All Implemented Interfaces:

TimeSource<Moment>
```
public final class SystemClock
extends Object
implements TimeSource<Moment>
```
Represents a clock which is based on the clock of the underlying operating system.

Author:

Meno Hochschild

Concurrency:
This class is immutable and can be used by multiple threads in parallel.

Field Summary

Fields
Modifier and Type	Field and Description
`static SystemClock`	`INSTANCE` Standard implementation.
`static SystemClock`	`MONOTONIC` Monotonic clock based on the best available clock of the underlying operating system.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`static Moment`	`currentMoment()` Equivalent to `SystemClock.INSTANCE.currentTime()`.
`Moment`	`currentTime()` Yields the current time.
`long`	`currentTimeInMicros()` Yields the current time in microseconds elapsed since [1970-01-01T00:00:00,000000Z].
`long`	`currentTimeInMillis()` Yields the current time in milliseconds elapsed since [1970-01-01T00:00:00,000Z].
`static ZonalClock`	`inLocalView()` Creates a local clock in system timezone.
`static ZonalClock`	`inPlatformView()` Creates a local clock in platform timezone.
`static ZonalClock`	`inZonalView(String tzid)` Creates a local clock in given timezone.
`static ZonalClock`	`inZonalView(TZID tzid)` Creates a local clock in given timezone.
`long`	`realTimeInMicros()` Yields the current time in microseconds elapsed since UTC epoch [1972-01-01T00:00:00,000000Z].
`SystemClock`	`recalibrated()` Recalibrates this instance and yields a new copy.
`SystemClock`	`synchronizedWith(TimeSource<?> clock)` Synchronizes this instance with given time source and yields a new copy.

Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - INSTANCE
```
public static final SystemClock INSTANCE
```
    Standard implementation.
    
    The system property "net.time4j.systemclock.nanoTime" controls if this clock is internally based on the expression System.nanoTime() (if property is set to "true") or System.currentTimeMillis() (default). The standard case is a clock which is affected by OS-triggered time jumps and user adjustments so there is no guarantee for a monotonic time.
  - MONOTONIC
```
public static final SystemClock MONOTONIC
```
    Monotonic clock based on the best available clock of the underlying operating system.
    
    A side effect of this implementation can be increased nominal precision up to nanoseconds although no guarantee is made to ensure nanosecond accuracy. The accuracy is often limited to milliseconds. However, the main focus and motivation is realizing a monotonic behaviour by delegating to the use of a monotonic clock of the underlying OS. Equivalent to CLOCK_MONOTONIC on a Linux-server.
    
    Since:
    
    3.2/4.1
    
    See Also:
    
    TickProvider.getNanos()
- Method Detail
  - currentTime
```
public Moment currentTime()
```
    Description copied from interface: TimeSource
    
    Yields the current time.
    
    Specified by:
    
    currentTime in interface TimeSource<Moment>
    
    Returns:
    
    current time in seconds (as UnixTime object or derivate)
  - currentTimeInMillis
```
public long currentTimeInMillis()
```
    Yields the current time in milliseconds elapsed since [1970-01-01T00:00:00,000Z].
    
    Returns:
    
    count of milliseconds since UNIX epoch without leap seconds
    
    See Also:
    
    currentTimeInMicros()
  - currentTimeInMicros
```
public long currentTimeInMicros()
```
    Yields the current time in microseconds elapsed since [1970-01-01T00:00:00,000000Z].
    
    If this clock is based only on System.currentTimeMillis() then this method will just multiply the millisecond value by factor 1000. On many operating systems the precision is limited to milliseconds. This is even true if this clock is based on System.nanoTime() because for purpose of calibration even here the method System.currentTimeMillis() must be accessed at least one time.
    
    Returns:
    
    count of microseconds since UNIX epoch without leap seconds
  - realTimeInMicros
```
public long realTimeInMicros()
```
    Yields the current time in microseconds elapsed since UTC epoch [1972-01-01T00:00:00,000000Z].
    
    Returns:
    
    count of microseconds since UTC epoch including leap seconds
    
    Since:
    
    3.2/4.1
    
    See Also:
    
    currentTimeInMicros()
  - inPlatformView
```
public static ZonalClock inPlatformView()
```
    Creates a local clock in platform timezone.
    
    Uses the standard clock SystemClock.INSTANCE and the platform timezone data.
    
    Returns:
    
    local clock in system timezone using the platform timezone data
    
    Since:
    
    3.3/4.2
    
    See Also:
    
    Timezone.ofSystem(), INSTANCE, TimeZone
  - inLocalView
```
public static ZonalClock inLocalView()
```
    Creates a local clock in system timezone.
    
    Uses the standard clock SystemClock.INSTANCE.
    
    Returns:
    
    cached local clock in system timezone using the best available timezone data
    
    See Also:
    
    Timezone.ofSystem(), INSTANCE
  - inZonalView
```
public static ZonalClock inZonalView(TZID tzid)
```
    Creates a local clock in given timezone.
    
    In order to achieve a monotonic zonal clock, users can use the expression new ZonalClock(SystemClock.MONOTONIC, tzid.
    
    Parameters:
    
    tzid - timezone id
    
    Returns:
    
    local clock in given timezone
    
    Throws:
    
    IllegalArgumentException - if given timezone cannot be loaded
    
    See Also:
    
    INSTANCE
  - inZonalView
```
public static ZonalClock inZonalView(String tzid)
```
    Creates a local clock in given timezone.
    
    In order to achieve a monotonic zonal clock, users can use the expression new ZonalClock(SystemClock.MONOTONIC, tzid.
    
    Parameters:
    
    tzid - timezone id
    
    Returns:
    
    local clock in given timezone
    
    Throws:
    
    IllegalArgumentException - if given timezone cannot be loaded
    
    See Also:
    
    INSTANCE
  - currentMoment
```
public static Moment currentMoment()
```
    Equivalent to SystemClock.INSTANCE.currentTime().
    
    Returns:
    
    current time using the standard implementation
    
    Since:
    
    2.3
    
    See Also:
    
    INSTANCE
  - recalibrated
```
public SystemClock recalibrated()
```
    Recalibrates this instance and yields a new copy.
    
    This method is only relevant if this clock is operated in monotonic mode. It is strongly advised not to recalibrate during or near a leap second. Please also note that this method might cause jumps in time - even backwards.
    
    Returns:
    
    new and recalibrated copy of this instance
    
    Since:
    
    3.2/4.1
    
    See Also:
    
    MONOTONIC
  - synchronizedWith
```
public SystemClock synchronizedWith(TimeSource<?> clock)
```
    Synchronizes this instance with given time source and yields a new copy.
    
    This method is only relevant if this clock is operated in monotonic mode. It is strongly advised not to recalibrate during or near a leap second. Please also note that this method might cause jumps in time - even backwards.
    
    Parameters:
    
    clock - another clock which this instance should be synchronized with
    
    Returns:
    
    synchronized copy of this instance
    
    Since:
    
    3.2/4.1
    
    See Also:
    
    MONOTONIC

Class SystemClock

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

INSTANCE

MONOTONIC

Method Detail

currentTime

currentTimeInMillis

currentTimeInMicros

realTimeInMicros

inPlatformView

inLocalView

inZonalView

inZonalView

currentMoment

recalibrated

synchronizedWith