## org.jfree.data.time
Class RegularTimePeriod

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

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

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` Deprecated. This was a bad idea, don't use it!

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
`static RegularTimePeriod` `createInstance(java.lang.Class c, java.util.Date millisecond, java.util.TimeZone zone)` Creates a time period that includes the specified millisecond, assuming the given time zone.
`static java.lang.Class` `downsize(java.lang.Class c)` Returns a subclass of `RegularTimePeriod` that is smaller than the specified class.
`java.util.Date` `getEnd()` Returns the date/time that marks the end of the time period.
`abstract long` `getFirstMillisecond()` Returns the first millisecond of the time period.
`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)` Deprecated. As of 1.0.3, you should avoid using this method (it creates a new Calendar instance every time it is called). You are advised to call `getFirstMillisecond(Calendar)` instead.
`abstract long` `getLastMillisecond()` Returns the last millisecond of the time period.
`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)` Deprecated. As of 1.0.3, you should avoid using this method (it creates a new Calendar instance every time it is called). You are advised to call `getLastMillisecond(Calendar)` instead.
`long` `getMiddleMillisecond()` Returns the millisecond closest to the middle of the time period.
`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)` Deprecated. As of 1.0.3, you should avoid using this method (it creates a new Calendar instance every time it is called). You are advised to call `getMiddleMillisecond(Calendar)` instead.
`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 void` `peg(java.util.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).
`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

  Deprecated. This was a bad idea, don't use it!
  A working calendar (recycle to avoid unnecessary object creation).

Constructor Detail

### RegularTimePeriod

    public RegularTimePeriod()

Method Detail

### createInstance

    public static RegularTimePeriod createInstance(java.lang.Class c,
                                                   java.util.Date millisecond,
                                                   java.util.TimeZone zone)

  Creates a time period that includes the specified millisecond, assuming the given time zone.

  Parameters:
    `c` - the time period class.
    `millisecond` - the time.
    `zone` - the time zone.
  Returns:
    The time period.

### downsize

    public static java.lang.Class downsize(java.lang.Class c)

  Returns a subclass of `RegularTimePeriod` that is smaller than the specified class.

  Parameters:
    `c` - a subclass of `RegularTimePeriod`.
  Returns:
    A class.

### 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 (possibly `null`).

### 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 (possibly `null`).

### getSerialIndex

    public abstract long getSerialIndex()

  Returns a serial index number for the time unit.

  Returns:
    The serial index number.

### peg

    public abstract void peg(java.util.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).

  Parameters:
    `calendar` - the calendar (`null` not permitted).
  Since:
    1.0.3

### getStart

    public java.util.Date getStart()

  Returns the date/time that marks the start of the time period. This method returns a new `Date` instance every time it is called.

  Specified by:
    `getStart` in interface `TimePeriod`
  Returns:
    The start date/time.
  See Also:
    `getFirstMillisecond()`

### getEnd

    public java.util.Date getEnd()

  Returns the date/time that marks the end of the time period. This method returns a new `Date` instance every time it is called.

  Specified by:
    `getEnd` in interface `TimePeriod`
  Returns:
    The end date/time.
  See Also:
    `getLastMillisecond()`

### getFirstMillisecond

    public abstract long getFirstMillisecond()

  Returns the first millisecond of the time period. 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.

  Returns:
    The first millisecond of the time period.
  See Also:
    `getLastMillisecond()`

### getFirstMillisecond

    public long getFirstMillisecond(java.util.TimeZone zone)

  Deprecated. As of 1.0.3, you should avoid using this method (it creates a new Calendar instance every time it is called). You are advised to call `getFirstMillisecond(Calendar)` instead.

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

  Parameters:
    `zone` - the time zone (`null` not permitted).
  Returns:
    The first millisecond of the time period.
  See Also:
    `getLastMillisecond(TimeZone)`

### 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 (`null` not permitted).
  Returns:
    The first millisecond of the time period.
  Throws:
    `java.lang.NullPointerException` - if `calendar,/code> is` null.
  See Also:
    `getLastMillisecond(Calendar)`

### getLastMillisecond

    public abstract long getLastMillisecond()

  Returns the last millisecond of the time period. 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.

  Returns:
    The last millisecond of the time period.
  See Also:
    `getFirstMillisecond()`

### getLastMillisecond

    public long getLastMillisecond(java.util.TimeZone zone)

  Deprecated. As of 1.0.3, you should avoid using this method (it creates a new Calendar instance every time it is called). You are advised to call `getLastMillisecond(Calendar)` instead.

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

  Parameters:
    `zone` - the time zone (`null` not permitted).
  Returns:
    The last millisecond of the time period.
  See Also:
    `getFirstMillisecond(TimeZone)`

### 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 (`null` not permitted).
  Returns:
    The last millisecond of the time period.
  See Also:
    `getFirstMillisecond(Calendar)`

### getMiddleMillisecond

    public long getMiddleMillisecond()

  Returns the millisecond closest to the middle of the time period.

  Returns:
    The middle millisecond.

### getMiddleMillisecond

    public long getMiddleMillisecond(java.util.TimeZone zone)

  Deprecated. As of 1.0.3, you should avoid using this method (it creates a new Calendar instance every time it is called). You are advised to call `getMiddleMillisecond(Calendar)` instead.

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

  Parameters:
    `zone` - the time zone (`null` not permitted).
  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.

  Overrides:
    `toString` in class `java.lang.Object`
  Returns:
    The string.