TimeMapper (STIL)

java.lang.Object
- uk.ac.starlink.table.TimeMapper

All Implemented Interfaces:

DomainMapper
```
public abstract class TimeMapper
extends java.lang.Object
implements DomainMapper
```
DomainMapper for mapping values to epochs in a common time scale.

Since:

12 Aug 2013

Field Summary

Fields
Modifier and Type	Field and Description
`static TimeMapper`	`DECIMAL_YEAR` Mapper for numeric values in decimal year (since 0 AD).
`static TimeMapper`	`ISO_8601` Mapper for ISO-8601 strings.
`static TimeMapper`	`JD` Mapper for numeric values in Julian Day.
`static TimeMapper`	`MJD` Mapper for numeric values in Modified Julian Date.
`static TimeMapper`	`UNIX_SECONDS` Mapper for numeric values (already) in unix seconds.

Constructor Summary

Constructors
Modifier	Constructor and Description
`protected`	`TimeMapper(java.lang.Class<?> sourceClass, java.lang.String sourceName, java.lang.String sourceDescription)` Constructor.

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method and Description
`java.lang.Class<?>`	`getSourceClass()` Returns the type of values from which this mapper instance can convert.
`java.lang.String`	`getSourceDescription()` Returns a description of the type of source values which this mapper can convert from.
`java.lang.String`	`getSourceName()` Returns a short name for the type of source values which this mapper can convert from.
`TimeDomain`	`getTargetDomain()` Returns `TimeDomain.INSTANCE`.
`static TimeMapper[]`	`getTimeMappers()` Returns a selection of time mapper instances.
`abstract double`	`toUnixSeconds(java.lang.Object sourceValue)` Maps a source value to time in seconds since the Unix epoch (1970-01-01T00:00:00).

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

- Field Detail
  - DECIMAL_YEAR
```
public static final TimeMapper DECIMAL_YEAR
```
    Mapper for numeric values in decimal year (since 0 AD).
  - MJD
```
public static final TimeMapper MJD
```
    Mapper for numeric values in Modified Julian Date.
  - JD
```
public static final TimeMapper JD
```
    Mapper for numeric values in Julian Day.
  - UNIX_SECONDS
```
public static final TimeMapper UNIX_SECONDS
```
    Mapper for numeric values (already) in unix seconds.
  - ISO_8601
```
public static final TimeMapper ISO_8601
```
    Mapper for ISO-8601 strings.
- Constructor Detail
  - TimeMapper
```
protected TimeMapper(java.lang.Class<?> sourceClass,
                     java.lang.String sourceName,
                     java.lang.String sourceDescription)
```
    Constructor.
    
    Parameters:
    
    sourceClass - source class
    
    sourceName - source type name
    
    sourceDescription - source type description
- Method Detail
  - getTargetDomain
```
public TimeDomain getTargetDomain()
```
    Returns TimeDomain.INSTANCE.
    
    Specified by:
    
    getTargetDomain in interface DomainMapper
    
    Returns:
    
    domain identifier
  - getSourceClass
```
public java.lang.Class<?> getSourceClass()
```
    Description copied from interface: DomainMapper
    
    Returns the type of values from which this mapper instance can convert. This should be as specific as possible to cover all the possible options, but in some cases that may mean it has simply to return Object.class.
    
    Specified by:
    
    getSourceClass in interface DomainMapper
    
    Returns:
    
    class of mappable source objects to which this mapper can be applied
  - getSourceName
```
public java.lang.String getSourceName()
```
    Description copied from interface: DomainMapper
    
    Returns a short name for the type of source values which this mapper can convert from.
    
    Specified by:
    
    getSourceName in interface DomainMapper
    
    Returns:
    
    mapper source type name
  - getSourceDescription
```
public java.lang.String getSourceDescription()
```
    Description copied from interface: DomainMapper
    
    Returns a description of the type of source values which this mapper can convert from.
    
    Specified by:
    
    getSourceDescription in interface DomainMapper
    
    Returns:
    
    mapper source type description
  - toUnixSeconds
```
public abstract double toUnixSeconds(java.lang.Object sourceValue)
```
    Maps a source value to time in seconds since the Unix epoch (1970-01-01T00:00:00). The time scale is generally assumed to be UTC, though conversions may not always be performed, for instance for values in which the intended time scale is not obvious.
    A java (IEEE 754) double has 52+1 bits of precision, which I make 52*ln(2)/ln(10)=15.65 decimal places, and a year contains 3.15e7 seconds, which gives you the following precisions:
    - epoch +/- 1.7 months: 1 nanosecond precision
    - epoch +/- 140 years: 1 microsecond precision
    - epoch +/- 140 kyears: 1 millisecond precision
    - epoch +/- 140 Myears: 1 second precision
    That means around microsecond precision for values near the current epoch (unless this software proves more long lasting than I anticipate). It should be OK for most purposes.
    Parameters:
    
    sourceValue - value in source domain
    
    Returns:
    
    number of seconds since midnight 1 Jan 1970
  - getTimeMappers
```
public static TimeMapper[] getTimeMappers()
```
    Returns a selection of time mapper instances.

Class TimeMapper

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

DECIMAL_YEAR

MJD

JD

UNIX_SECONDS

ISO_8601

Constructor Detail

TimeMapper

Method Detail

getTargetDomain

getSourceClass

getSourceName

getSourceDescription

toUnixSeconds

getTimeMappers