Class DT_DATE_DURATION PreviousNext

note
description:

    "Date durations (Gregorian calendar)"

library:    "Gobo Eiffel Time Library"
author:     "Eric Bezault <ericb@gobosoft.com>"
copyright:  "Copyright (c) 2000-2001, Eric Bezault and others"
license:    "MIT License"
class interface
DT_DATE_DURATION
inherit
DT_DURATION
    KL_PART_COMPARABLE
    HASHABLE
    KL_CLONABLE
DT_DATE_VALUE
DT_GREGORIAN_CALENDAR
create
make (y, m, d: INTEGER)
        -- Create a new date duration.
    ensure
        year_set: year = y
        month_set: month = m
        day_set: day = d
make_definite (d: INTEGER)
        -- Create a new definite date duration.
    ensure
        is_definite: is_definite
        day_set: day = d
feature -- Access
year: INTEGER
        -- Year
        -- (From DT_DATE_VALUE.)
month: INTEGER
        -- Month
        -- (From DT_DATE_VALUE.)
day: INTEGER
        -- Day
        -- (From DT_DATE_VALUE.)
date (a_date: DT_DATE): DT_DATE
        -- Addition of current duration to a_date
        -- (Create a new object at each call.)
        -- (From absolute_time in DT_DURATION.)
    require
        a_date_not_void: a_date /= Void
    ensure
        date_not_void: Result /= Void
        definition: Result.is_equal (a_date + Current)
hash_code: INTEGER
        -- Hash code value
        -- (From HASHABLE.)
    ensure
        good_hash_value: Result >= 0
feature -- Status report
is_definite: BOOLEAN
        -- Is current duration independant of the date
        -- on which it applies (use of day only)
        -- or not (use of year, month and day)?
    ensure
        definition: Result = (year = 0 and month = 0)
is_canonical (a_date: like date): BOOLEAN
        -- Has current duration a canonical form
        -- when to be added to a_date?
    require
        a_date_not_void: a_date /= Void
    ensure
        positive_definition: Result implies ((a_date <= a_date + Current) implies
            (year >= 0 and month >= 0 and month < Months_in_year and day >= 0 and
            ((day >= (a_date + Current).day implies
                day < (a_date + Current).days_in_previous_month) or
            (day < (a_date + Current).day implies
                day < (a_date + Current).days_in_current_month))))
        negative_definition: Result implies ((a_date >= a_date + Current) implies
            (year <= 0 and month <= 0 and month > -Months_in_year and
            day <= 0 and day > -(a_date + Current).days_in_current_month))
feature -- Status setting
set_definite (a_date: like date)
        -- Set current duration to be definite
        -- when to be added to a_date.
    require
        a_date_not_void: a_date /= Void
    ensure
        is_definite: is_definite
        same_duration: (a_date + Current).is_equal (a_date + old cloned_object)
set_canonical (a_date: like date)
        -- Set current duration to be canonical
        -- when to be added to a_date.
    require
        a_date_not_void: a_date /= Void
    ensure
        is_canonical: is_canonical (a_date)
        same_duration: (a_date + Current).is_equal (a_date + old cloned_object)
feature -- Setting
set_year_month_day (y, m, d: INTEGER)
        -- Set year to y, month to m and day to d.
    ensure
        year_set: year = y
        month_set: month = m
        day_set: day = d
set_year (y: INTEGER)
        -- Set year to y.
    ensure
        year_set: year = y
        same_month: month = old month
        same_day: day = old day
set_month (m: INTEGER)
        -- Set month to m.
    ensure
        month_set: month = m
        same_year: year = old year
        same_day: day = old day
set_day (d: INTEGER)
        -- Set day to d.
    ensure
        day_set: day = d
        same_year: year = old year
        same_month: month = old month
feature -- Element change
add_years_months_days (y, m, d: INTEGER)
        -- Add y years, m months and d days to current duration.
    ensure
        years_added: year = old year + y
        months_added: month = old month + m
        days_added: day = old day + d
add_years (y: INTEGER)
        -- Add y years to current duration.
    ensure
        years_added: year = old year + y
add_months (m: INTEGER)
        -- Add m months to current duration.
    ensure
        months_added: month = old month + m
add_days (d: INTEGER)
        -- Add d days to current duration.
    ensure
        days_added: day = old day + d
feature -- Basic operations
infix "+" (other: like Current): like Current
        -- Sum of current duration with other
        -- (From DT_DURATION.)
    require
        other_not_void: other /= Void
    ensure
        addition_not_void: Result /= Void
infix "-" (other: like Current): like Current
        -- Difference with other
        -- (From DT_DURATION.)
    require
        other_not_void: other /= Void
    ensure
        subtraction_not_void: Result /= Void
prefix "+": like Current
        -- Unary plus
        -- (From DT_DURATION.)
    ensure
        unary_plus_not_void: Result /= Void
        same_object: Result = Current
prefix "-": like Current
        -- Unary minus
        -- (From DT_DURATION.)
    ensure
        unary_minus_not_void: Result /= Void
feature -- Comparison
infix "<" (other: like Current): BOOLEAN
        -- Is current date duration less than other?
        -- (From KL_PART_COMPARABLE.)
    require
        other_not_void: other /= Void
infix "<=" (other: like Current): BOOLEAN
        -- Is current object less than or equal to other?
        -- (From KL_PART_COMPARABLE.)
    require
        other_not_void: other /= Void
    ensure
        definition: Result = ((Current < other) or is_equal (other))
infix ">=" (other: like Current): BOOLEAN
        -- Is current object greater than or equal to other?
        -- (From KL_PART_COMPARABLE.)
    require
        other_not_void: other /= Void
    ensure
        definition: Result = (other <= Current)
infix ">" (other: like Current): BOOLEAN
        -- Is current object greater than other?
        -- (From KL_PART_COMPARABLE.)
    require
        other_not_void: other /= Void
    ensure
        definition: Result = ((other < Current) or is_equal (other))
is_equal (other: like Current): BOOLEAN
        -- Is current date duration equal to other?
        -- (From GENERAL.)
    require
        other_not_void: other /= Void
    ensure
        symmetric: Result implies other.is_equal (Current)
        consistent: standard_is_equal (other) implies Result
same_date_duration (other: DT_DATE_DURATION): BOOLEAN
        -- Is current date duration equal to other?
    require
        other_not_void: other /= Void
    ensure
        definition: Result = ((day = other.day) and
            ((year * Months_in_year + month) =
                (other.year * Months_in_year + other.month)))
feature -- Duplication
copy (other: like Current)
        -- Copy other to current duration.
        -- (From GENERAL.)
    require
        other_not_void: other /= Void
        type_identity: same_type (other)
    ensure
        is_equal: is_equal (other)
feature -- Conversion
to_date_time_duration: DT_DATE_TIME_DURATION
        -- Date time duration equivalent to current date duration
    ensure
        date_time_duration_not_void: Result /= Void
        year_set: Result.year = year
        month_set: Result.month = month
        day_set: Result.day = day
        hour_set: Result.hour = 0
        minute_set: Result.minute = 0
        second_set: Result.second = 0
        millisecond_set: Result.millisecond = 0
to_canonical (a_date: like date): like Current
        -- Canonical version of current duration
        -- when to be added to a_date
    require
        a_date_not_void: a_date /= Void
    ensure
        canonical_duration_not_void: Result /= Void
        is_canonical: Result.is_canonical (a_date)
        same_duration: (a_date + Current).is_equal (a_date + Result)
to_definite (a_date: like date): like Current
        -- Definite version of current duration
        -- when to be added to a_date
    require
        a_date_not_void: a_date /= Void
    ensure
        definite_duration_not_void: Result /= Void
        is_definite: Result.is_definite
        same_duration: (a_date + Current).is_equal (a_date + Result)
feature -- Output
out: STRING
        -- Printable representation (year/month/day)
        -- (From GENERAL.)
    ensure
        out_not_void: Result /= Void
date_out: STRING
        -- Printable representation (year/month/day)
        -- (From DT_DATE_VALUE.)
    ensure
        date_out_not_void: Result /= Void
append_to_string (a_string: STRING)
        -- Append printable representation
        -- (year/month/day) to a_string.
        -- (From DT_DATE_VALUE.)
    require
        a_string_not_void: a_string /= Void
append_date_to_string (a_string: STRING)
        -- Append printable representation
        -- (year/month/day) to a_string.
        -- (From DT_DATE_VALUE.)
    require
        a_string_not_void: a_string /= Void
feature -- Year
leap_year (y: INTEGER): BOOLEAN
        -- Is y a leap year?
        -- (From DT_GREGORIAN_CALENDAR.)
Months_in_year: INTEGER
        -- Number of months in a year
        -- (From DT_GREGORIAN_CALENDAR.)
    ensure
        definition: Result = (December - Januray + 1)
Days_in_year: INTEGER
Days_in_leap_year: INTEGER
        -- Number of days in a (leap) year
        -- (From DT_GREGORIAN_CALENDAR.)
Days_in_400_years: INTEGER
Days_in_100_years: INTEGER
Days_in_4_years: INTEGER
Days_in_3_years: INTEGER
Days_in_3_leap_years: INTEGER
Days_in_2_years: INTEGER
Days_in_2_leap_years: INTEGER
        -- Number of days in multiple years
        -- (From DT_GREGORIAN_CALENDAR.)
feature -- Month
January: INTEGER
February: INTEGER
March: INTEGER
April: INTEGER
May: INTEGER
June: INTEGER
July: INTEGER
August: INTEGER
September: INTEGER
October: INTEGER
November: INTEGER
December: INTEGER
        -- Months
        -- (From DT_GREGORIAN_CALENDAR.)
days_in_month (m, y: INTEGER): INTEGER
        -- Number of days in month m of year y
        -- (From DT_GREGORIAN_CALENDAR.)
    require
        m_large_enough: m >= January
        m_small_enough: m <= December
    ensure
        at_least_one: Result >= 1
        max_days_in_month: Result <= Max_days_in_month
Max_days_in_month: INTEGER
        -- Maximum number of days in a month
        -- (From DT_GREGORIAN_CALENDAR.)
days_at_month (m, y: INTEGER): INTEGER
        -- Number of days from beginning of year
        -- y until beginning of month m
        -- (From DT_GREGORIAN_CALENDAR.)
    require
        m_large_enough: m >= January
        m_small_enough: m <= December
    ensure
        days_positive: Result >= 0
feature -- Week day
Sunday: INTEGER
Monday: INTEGER
Tuesday: INTEGER
Wednesday: INTEGER
Thursday: INTEGER
Friday: INTEGER
Saturday: INTEGER
        -- Week days
        -- (From DT_GREGORIAN_CALENDAR.)
Days_in_week: INTEGER
        -- Number of days in a week
        -- (From DT_GREGORIAN_CALENDAR.)
    ensure
        definition: Result = (Saturday - Sunday + 1)
next_day (d: INTEGER): INTEGER
        -- Week day after d
        -- (From DT_GREGORIAN_CALENDAR.)
    require
        d_large_enough: d >= Sunday
        d_small_enough: d <= Saturday
    ensure
        sunday_definition: (d = Sunday) implies (Result = Monday)
        monday_definition: (d = Monday) implies (Result = Tuesday)
        tuesday_definition: (d = Tuesday) implies (Result = Wednesday)
        wednesday_definition: (d = Wednesday) implies (Result = Thursday)
        thursday_definition: (d = Thursday) implies (Result= Friday)
        friday_definition: (d = Friday) implies (Result = Saturday)
        saturday_definition: (d = Saturday) implies (Result = Sunday)
previous_day (d: INTEGER): INTEGER
        -- Week day before d
        -- (From DT_GREGORIAN_CALENDAR.)
    require
        d_large_enough: d >= Sunday
        d_small_enough: d <= Saturday
    ensure
        sunday_definition: (d = Sunday) implies (Result = Saturday)
        monday_definition: (d = Monday) implies (Result = Sunday)
        tuesday_definition: (d = Tuesday) implies (Result = Monday)
        wednesday_definition: (d = Wednesday) implies (Result = Tuesday)
        thursday_definition: (d = Thursday) implies (Result= Wednesday)
        friday_definition: (d = Friday) implies (Result = Thursday)
        saturday_definition: (d = Saturday) implies (Result = Friday)
feature -- Time
Seconds_in_minute: INTEGER
        -- Number of seconds in a minute
        -- (From DT_GREGORIAN_CALENDAR.)
Seconds_in_hour: INTEGER
        -- Number of seconds in an hour
        -- (From DT_GREGORIAN_CALENDAR.)
Seconds_in_day: INTEGER
        -- Number of seconds in a day
        -- (From DT_GREGORIAN_CALENDAR.)
Milliseconds_in_day: INTEGER
        -- Number of milliseconds in a day
        -- (From DT_GREGORIAN_CALENDAR.)
Minutes_in_hour: INTEGER
        -- Number of minutes in an hour
        -- (From DT_GREGORIAN_CALENDAR.)
Hours_in_day: INTEGER
        -- Number of hours in a day
        -- (From DT_GREGORIAN_CALENDAR.)
feature -- Epoch
Epoch_year: INTEGER
Epoch_month: INTEGER
Epoch_day: INTEGER
        -- Epoch date (1 Jan 1970)
        -- (From DT_GREGORIAN_CALENDAR.)
epoch_days (y, m, d: INTEGER): INTEGER
        -- Number of days since epoch date (1 Jan 1970)
        -- (From DT_GREGORIAN_CALENDAR.)
    require
        m_large_enough: m >= January
        m_small_enough: m <= December
        d_large_enough: d >= 1
        d_small_enough: d <= days_in_month (m, y)
end -- class DT_DATE_DURATION

Copyright 2000-2001, Eric Bezault
mailto:
ericb@gobosoft.com
http:
//www.gobosoft.com
Last Updated: 9 April 2001

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