Class Day

All Implemented Interfaces:
Serializable, Comparable, MonthConstants, TimePeriod

public class Day
extends RegularTimePeriod
implements Serializable
Represents a single day in the range 1-Jan-1900 to 31-Dec-9999. This class is immutable, which is a requirement for all RegularTimePeriod subclasses.
See Also:
Serialized Form
  • Field Details

  • Constructor Details

    • Day

      public Day()
      Creates a new instance, derived from the system date/time. The time zone and locale are determined by the calendar returned by RegularTimePeriod.getCalendarInstance().
    • Day

      public Day​(int day, int month, int year)
      Constructs a new one day time period. The time zone and locale are determined by the calendar returned by RegularTimePeriod.getCalendarInstance().
      Parameters:
      day - the day-of-the-month.
      month - the month (1 to 12).
      year - the year (1900 <= year <= 9999).
    • Day

      public Day​(SerialDate serialDate)
      Constructs a new one day time period. The time zone and locale are determined by the calendar returned by RegularTimePeriod.getCalendarInstance().
      Parameters:
      serialDate - the day (null not permitted).
    • Day

      public Day​(Date time)
      Constructs a new instance, based on a particular date/time. The time zone and locale are determined by the calendar returned by RegularTimePeriod.getCalendarInstance().
      Parameters:
      time - the time (null not permitted).
      See Also:
      Day(Date, TimeZone, Locale)
    • Day

      public Day​(Date time, TimeZone zone, Locale locale)
      Constructs a new instance, based on a particular date/time and time zone.
      Parameters:
      time - the date/time (null not permitted).
      zone - the time zone (null not permitted).
      locale - the locale (null not permitted).
    • Day

      public Day​(Date time, Calendar calendar)
      Constructs a new instance, based on a particular date/time. The time zone and locale are determined by the calendar parameter.
      Parameters:
      time - the date/time (null not permitted).
      calendar - the calendar to use for calculations (null not permitted).
  • Method Details

    • getSerialDate

      Returns the day as a SerialDate. Note: the reference that is returned should be an instance of an immutable SerialDate (otherwise the caller could use the reference to alter the state of this Day instance, and Day is supposed to be immutable).
      Returns:
      The day as a SerialDate.
    • getYear

      public int getYear()
      Returns the year.
      Returns:
      The year.
    • getMonth

      public int getMonth()
      Returns the month.
      Returns:
      The month.
    • getDayOfMonth

      public int getDayOfMonth()
      Returns the day of the month.
      Returns:
      The day of the month.
    • getFirstMillisecond

      public long getFirstMillisecond()
      Returns the first millisecond of the day. This will be determined relative to the time zone specified in the constructor, or in the calendar instance passed in the most recent call to the peg(Calendar) method.
      Specified by:
      getFirstMillisecond in class RegularTimePeriod
      Returns:
      The first millisecond of the day.
      See Also:
      getLastMillisecond()
    • getLastMillisecond

      public long getLastMillisecond()
      Returns the last millisecond of the day. This will be determined relative to the time zone specified in the constructor, or in the calendar instance passed in the most recent call to the peg(Calendar) method.
      Specified by:
      getLastMillisecond in class RegularTimePeriod
      Returns:
      The last millisecond of the day.
      See Also:
      getFirstMillisecond()
    • peg

      public void peg​(Calendar calendar)
      Recalculates the start date/time and end date/time for this time period relative to the supplied calendar (which incorporates a time zone).
      Specified by:
      peg in class RegularTimePeriod
      Parameters:
      calendar - the calendar (null not permitted).
    • previous

      Returns the day preceding this one. No matter what time zone and locale this instance was created with, the returned instance will use the default calendar for time calculations, obtained with RegularTimePeriod.getCalendarInstance().
      Specified by:
      previous in class RegularTimePeriod
      Returns:
      The day preceding this one.
    • next

      Returns the day following this one, or null if some limit has been reached. No matter what time zone and locale this instance was created with, the returned instance will use the default calendar for time calculations, obtained with RegularTimePeriod.getCalendarInstance().
      Specified by:
      next in class RegularTimePeriod
      Returns:
      The day following this one, or null if some limit has been reached.
    • getSerialIndex

      public long getSerialIndex()
      Returns a serial index number for the day.
      Specified by:
      getSerialIndex in class RegularTimePeriod
      Returns:
      The serial index number.
    • getFirstMillisecond

      public long getFirstMillisecond​(Calendar calendar)
      Returns the first millisecond of the day, evaluated using the supplied calendar (which determines the time zone).
      Specified by:
      getFirstMillisecond in class RegularTimePeriod
      Parameters:
      calendar - calendar to use (null not permitted).
      Returns:
      The start of the day as milliseconds since 01-01-1970.
      Throws:
      NullPointerException - if calendar is null.
      See Also:
      RegularTimePeriod.getLastMillisecond(Calendar)
    • getLastMillisecond

      public long getLastMillisecond​(Calendar calendar)
      Returns the last millisecond of the day, evaluated using the supplied calendar (which determines the time zone).
      Specified by:
      getLastMillisecond in class RegularTimePeriod
      Parameters:
      calendar - calendar to use (null not permitted).
      Returns:
      The end of the day as milliseconds since 01-01-1970.
      Throws:
      NullPointerException - if calendar is null.
      See Also:
      RegularTimePeriod.getFirstMillisecond(Calendar)
    • equals

      public boolean equals​(Object obj)
      Tests the equality of this Day object to an arbitrary object. Returns true if the target is a Day instance or a SerialDate instance representing the same day as this object. In all other cases, returns false.
      Overrides:
      equals in class Object
      Parameters:
      obj - the object (null permitted).
      Returns:
      A flag indicating whether or not an object is equal to this day.
    • hashCode

      public int hashCode()
      Returns a hash code for this object instance. The approach described by Joshua Bloch in "Effective Java" has been used here:

      http://developer.java.sun.com/developer/Books/effectivejava /Chapter3.pdf

      Overrides:
      hashCode in class Object
      Returns:
      A hash code.
    • compareTo

      public int compareTo​(Object o1)
      Returns an integer indicating the order of this Day object relative to the specified object: negative == before, zero == same, positive == after.
      Specified by:
      compareTo in interface Comparable
      Parameters:
      o1 - the object to compare.
      Returns:
      negative == before, zero == same, positive == after.
    • toString

      public String toString()
      Returns a string representing the day.
      Overrides:
      toString in class RegularTimePeriod
      Returns:
      A string representing the day.
    • parseDay

      public static Day parseDay​(String s)
      Parses the string argument as a day.

      This method is required to recognise YYYY-MM-DD as a valid format. Anything else, for now, is a bonus.

      Parameters:
      s - the date string to parse.
      Returns:
      null if the string does not contain any parseable string, the day otherwise.