Package io.keikai.model.impl.sys

Class CalendarUtilImpl

java.lang.Object

io.keikai.model.impl.sys.CalendarUtilImpl

All Implemented Interfaces:

CalendarUtil

public class CalendarUtilImpl
extends Object
implements CalendarUtil

Converts between Date and Excel's serial date number (days since 1899-12-30 in 1900-windowing mode, days since 1903-12-31 in 1904-windowing mode; fractional days encode time-of-day).

POI removal: clean-room reimplementation derived from Excel's documented date-serial behaviour and ECMA-376 Part 1 §18.17.4.1. Algorithm matches Apache POI's DateUtil (Apache License 2.0) to keep on-disk semantics identical:

• 1900-mode: serial 1 = 1900-01-01; serial 60 is reserved for the fictitious 1900-02-29 (Excel preserves Lotus 1-2-3's bug for interchange compatibility).
• 1904-mode: serial 0 = 1904-01-01.
• Hours/minutes/seconds/millis are extracted from the local-zone calendar fields rather than from Date.getTime() to avoid DST-induced drift (POI behaviour, see DateUtil#getExcelDate).

Since:

3.5.0

Author:

dennis

Constructor Summary

Constructors

Constructor	Description
CalendarUtilImpl()

Method Summary

Modifier and Type	Method	Description
double	dateToDoubleValue(Date value)
double	dateToDoubleValue(Date date, boolean date1904)
Date	doubleValueToDate(double val)
Date	doubleValueToDate(double date, boolean date1904)

Methods inherited from class java.lang.Object

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

Constructor Details

CalendarUtilImpl

public CalendarUtilImpl()

Method Details

doubleValueToDate

public Date doubleValueToDate(double date,
 boolean date1904)

Specified by:

doubleValueToDate in interface CalendarUtil

dateToDoubleValue

public double dateToDoubleValue(Date date,
 boolean date1904)

Specified by:

dateToDoubleValue in interface CalendarUtil

doubleValueToDate

public Date doubleValueToDate(double val)

Specified by:

doubleValueToDate in interface CalendarUtil

dateToDoubleValue

public double dateToDoubleValue(Date value)

Specified by:

dateToDoubleValue in interface CalendarUtil