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java.lang.Objectuk.ac.starlink.table.TimeMapper
public abstract class TimeMapper
DomainMapper for mapping values to epochs in a common time scale. The target domain is doubles giving the number of 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:
Field Summary | |
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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 String |
TARGET_NAME
Returns target domain name ("Time"). |
static TimeMapper |
UNIX_SECONDS
Mapper for numeric values (already) in unix seconds. |
Constructor Summary | |
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protected |
TimeMapper(Class sourceClass,
String sourceName,
String sourceDescription)
Constructor. |
Method Summary | |
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Class |
getSourceClass()
Returns the type of values from which this mapper instance can convert. |
String |
getSourceDescription()
Returns a description of the type of source values which this mapper can convert from. |
String |
getSourceName()
Returns a short name for the type of source values which this mapper can convert from. |
String |
getTargetName()
Returns TARGET_NAME . |
static TimeMapper[] |
getTimeMappers()
Returns a selection of time mapper instances. |
abstract double |
toUnixSeconds(Object sourceValue)
Maps a source value to time in seconds since the Unix epoch. |
Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Field Detail |
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public static final String TARGET_NAME
public static final TimeMapper DECIMAL_YEAR
public static final TimeMapper MJD
public static final TimeMapper JD
public static final TimeMapper UNIX_SECONDS
public static final TimeMapper ISO_8601
Constructor Detail |
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protected TimeMapper(Class sourceClass, String sourceName, String sourceDescription)
sourceClass
- sourceName
- source type namesourceDescription
- source type descriptionMethod Detail |
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public final String getTargetName()
TARGET_NAME
.
getTargetName
in interface DomainMapper
public Class getSourceClass()
DomainMapper
getSourceClass
in interface DomainMapper
public String getSourceName()
DomainMapper
getSourceName
in interface DomainMapper
public String getSourceDescription()
DomainMapper
getSourceDescription
in interface DomainMapper
public abstract double toUnixSeconds(Object sourceValue)
sourceValue
- value in source domain
public static TimeMapper[] getTimeMappers()
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Copyright © 2004 CLRC: Central Laboratory of the Research Councils. All rights reserved. | ||||||||
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