## org.jfree.data.time
Class RegularTimePeriod

    java.lang.Object
      org.jfree.data.time.RegularTimePeriod

All Implemented Interfaces:
  java.lang.Comparable, org.jfree.date.MonthConstants, TimePeriod

Direct Known Subclasses:
  Day, FixedMillisecond, Hour, Millisecond, Minute, Month, Quarter, Second, Week, Year

public abstract class RegularTimePeriod
extends java.lang.Object
implements TimePeriod, java.lang.Comparable, org.jfree.date.MonthConstants

An abstract class representing a unit of time.

Convenient methods are provided for calculating the next and previous time periods.

Conversion methods are defined that return the first and last milliseconds of the time period. The results from these methods are timezone dependent.

This class is immutable, and all subclasses should be immutable also.

Field Summary
`static java.util.TimeZone` `DEFAULT_TIME_ZONE` The default time zone.
`static java.util.Calendar` `WORKING_CALENDAR` A working calendar (recycle to avoid unnecessary object creation).

Fields inherited from interface org.jfree.date.MonthConstants
`APRIL, AUGUST, DECEMBER, FEBRUARY, JANUARY, JULY, JUNE, MARCH, MAY, NOVEMBER, OCTOBER, SEPTEMBER`

Constructor Summary
`RegularTimePeriod()`

Method Summary
`java.util.Date` `getEnd()` Returns the date/time that marks the end of the time period.
`long` `getFirstMillisecond()` Returns the first millisecond of the time period, evaluated in the default time zone.
`abstract long` `getFirstMillisecond(java.util.Calendar calendar)` Returns the first millisecond of the time period, evaluated using the supplied calendar (which incorporates a timezone).
`long` `getFirstMillisecond(java.util.TimeZone zone)` Returns the first millisecond of the time period, evaluated within a specific time zone.
`long` `getLastMillisecond()` Returns the last millisecond of the time period, evaluated in the default time zone.
`abstract long` `getLastMillisecond(java.util.Calendar calendar)` Returns the last millisecond of the time period, evaluated using the supplied calendar (which incorporates a timezone).
`long` `getLastMillisecond(java.util.TimeZone zone)` Returns the last millisecond of the time period, evaluated within a specific time zone.
`long` `getMiddleMillisecond()` Returns the millisecond closest to the middle of the time period, evaluated in the default time zone.
`long` `getMiddleMillisecond(java.util.Calendar calendar)` Returns the millisecond closest to the middle of the time period, evaluated using the supplied calendar (which incorporates a timezone).
`long` `getMiddleMillisecond(java.util.TimeZone zone)` Returns the millisecond closest to the middle of the time period, evaluated within a specific time zone.
`abstract long` `getSerialIndex()` Returns a serial index number for the time unit.
`java.util.Date` `getStart()` Returns the date/time that marks the start of the time period.
`abstract RegularTimePeriod` `next()` Returns the time period following this one, or null if some limit has been reached.
`abstract RegularTimePeriod` `previous()` Returns the time period preceding this one, or null if some lower limit has been reached.
`java.lang.String` `toString()` Returns a string representation of the time period.

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

Methods inherited from interface java.lang.Comparable
`compareTo`

Field Detail

### DEFAULT_TIME_ZONE

    public static final java.util.TimeZone DEFAULT_TIME_ZONE

  The default time zone.

### WORKING_CALENDAR

    public static final java.util.Calendar WORKING_CALENDAR

  A working calendar (recycle to avoid unnecessary object creation).

Constructor Detail

### RegularTimePeriod

    public RegularTimePeriod()

Method Detail

### previous

    public abstract RegularTimePeriod previous()

  Returns the time period preceding this one, or null if some lower limit has been reached.

  Returns:
    the previous time period.

### next

    public abstract RegularTimePeriod next()

  Returns the time period following this one, or null if some limit has been reached.

  Returns:
    the next time period.

### getSerialIndex

    public abstract long getSerialIndex()

  Returns a serial index number for the time unit.

  Returns:
    the serial index number.

### getStart

    public java.util.Date getStart()

  Returns the date/time that marks the start of the time period.

  Specified by:
    `getStart` in interface `TimePeriod`
  Returns:
    the start date/time.

### getEnd

    public java.util.Date getEnd()

  Returns the date/time that marks the end of the time period.

  Specified by:
    `getEnd` in interface `TimePeriod`
  Returns:
    the end date/time.

### getFirstMillisecond

    public long getFirstMillisecond()

  Returns the first millisecond of the time period, evaluated in the default time zone.

  Returns:
    the first millisecond of the time period.

### getFirstMillisecond

    public long getFirstMillisecond(java.util.TimeZone zone)

  Returns the first millisecond of the time period, evaluated within a specific time zone.

  Parameters:
    `zone` - the time zone.
  Returns:
    the first millisecond of the time period.

### getFirstMillisecond

    public abstract long getFirstMillisecond(java.util.Calendar calendar)

  Returns the first millisecond of the time period, evaluated using the supplied calendar (which incorporates a timezone).

  Parameters:
    `calendar` - the calendar.
  Returns:
    the first millisecond of the time period.

### getLastMillisecond

    public long getLastMillisecond()

  Returns the last millisecond of the time period, evaluated in the default time zone.

  Returns:
    the last millisecond of the time period.

### getLastMillisecond

    public long getLastMillisecond(java.util.TimeZone zone)

  Returns the last millisecond of the time period, evaluated within a specific time zone.

  Parameters:
    `zone` - the time zone.
  Returns:
    the last millisecond of the time period.

### getLastMillisecond

    public abstract long getLastMillisecond(java.util.Calendar calendar)

  Returns the last millisecond of the time period, evaluated using the supplied calendar (which incorporates a timezone).

  Parameters:
    `calendar` - the calendar.
  Returns:
    the last millisecond of the time period.

### getMiddleMillisecond

    public long getMiddleMillisecond()

  Returns the millisecond closest to the middle of the time period, evaluated in the default time zone.

  Returns:
    The middle millisecond.

### getMiddleMillisecond

    public long getMiddleMillisecond(java.util.TimeZone zone)

  Returns the millisecond closest to the middle of the time period, evaluated within a specific time zone.

  Parameters:
    `zone` - the time zone.
  Returns:
    The middle millisecond.

### getMiddleMillisecond

    public long getMiddleMillisecond(java.util.Calendar calendar)

  Returns the millisecond closest to the middle of the time period, evaluated using the supplied calendar (which incorporates a timezone).

  Parameters:
    `calendar` - the calendar.
  Returns:
    The middle millisecond.

### toString

    public java.lang.String toString()

  Returns a string representation of the time period.

  Returns:
    The string.