org.goda.time.format

Class DateTimeFormatter

java.lang.Object

org.goda.time.format.DateTimeFormatter

public class DateTimeFormatter
extends Object

Controls the printing and parsing of a datetime to and from a string.

This class is the main API for printing and parsing used by most applications. Instances of this class are created via one of three factory classes:

• DateTimeFormat - formats by pattern and style
• ISODateTimeFormat - ISO8601 formats
• DateTimeFormatterBuilder - complex formats created via method calls

An instance of this class holds a reference internally to one printer and one parser. It is possible that one of these may be null, in which case the formatter cannot print/parse. This can be checked via the isPrinter() and isParser() methods.

The underlying printer/parser can be altered to behave exactly as required by using one of the decorator modifiers:

• withLocale(Locale) - returns a new formatter that uses the specified locale
• withZone(DateTimeZone) - returns a new formatter that uses the specified time zone
• withChronology(Chronology) - returns a new formatter that uses the specified chronology
• withOffsetParsed() - returns a new formatter that returns the parsed time zone offset

Each of these returns a new formatter (instances of this class are immutable).

The main methods of the class are the printXxx and parseXxx methods. These are used as follows:

 // print using the defaults (default locale, chronology/zone of the datetime)
 String dateStr = formatter.print(dt);
 // print using the French locale
 String dateStr = formatter.withLocale(Locale.FRENCH).print(dt);
 // print using the UTC zone
 String dateStr = formatter.withZone(DateTimeZone.UTC).print(dt);
 
 // parse using the Paris zone
 DateTime date = formatter.withZone(DateTimeZone.forID("Europe/Paris")).parseDateTime(str);
 

Since:

1.0

Author:

Brian S O'Neill, Stephen Colebourne, Fredrik Borgh

Constructor Summary

Constructors

Constructor and Description
DateTimeFormatter(DateTimePrinter printer, DateTimeParser parser) Creates a new formatter, however you will normally use the factory or the builder.

Method Summary

Methods

Modifier and Type	Method and Description
Chronology	getChronolgy() Gets the chronology to use as an override.
Locale	getLocale() Gets the locale that will be used for printing and parsing.
DateTimeParser	getParser() Gets the internal parser object that performs the real parsing work.
Integer	getPivotYear() Gets the pivot year to use as an override.
DateTimePrinter	getPrinter() Gets the internal printer object that performs the real printing work.
DateTimeZone	getZone() Gets the zone to use as an override.
boolean	isOffsetParsed() Checks whether the offset from the string is used as the zone of the parsed datetime.
boolean	isParser() Is this formatter capable of parsing.
boolean	isPrinter() Is this formatter capable of printing.
DateTime	parseDateTime(String text) Parses a datetime from the given text, returning a new DateTime.
int	parseInto(ReadWritableInstant instant, String text, int position) Parses a datetime from the given text, at the given position, saving the result into the fields of the given ReadWritableInstant.
long	parseMillis(String text) Parses a datetime from the given text, returning the number of milliseconds since the epoch, 1970-01-01T00:00:00Z.
MutableDateTime	parseMutableDateTime(String text) Parses a datetime from the given text, returning a new MutableDateTime.
String	print(long instant) Prints a millisecond instant to a String.
String	print(ReadableInstant instant) Prints a ReadableInstant to a String.
String	print(ReadablePartial partial) Prints a ReadablePartial to a new String.
void	printTo(StringBuffer buf, long instant) Prints an instant from milliseconds since 1970-01-01T00:00:00Z, using ISO chronology in the default DateTimeZone.
void	printTo(StringBuffer buf, ReadableInstant instant) Prints a ReadableInstant, using the chronology supplied by the instant.
void	printTo(StringBuffer buf, ReadablePartial partial) Prints a ReadablePartial.
DateTimeFormatter	withChronology(Chronology chrono) Returns a new formatter that will use the specified chronology in preference to that of the printed object, or ISO on a parse.
DateTimeFormatter	withLocale(Locale locale) Returns a new formatter with a different locale that will be used for printing and parsing.
DateTimeFormatter	withOffsetParsed() Returns a new formatter that will create a datetime with a time zone equal to that of the offset of the parsed string.
DateTimeFormatter	withPivotYear(int pivotYear) Returns a new formatter that will use the specified pivot year for two digit year parsing in preference to that stored in the parser.
DateTimeFormatter	withPivotYear(Integer pivotYear) Returns a new formatter that will use the specified pivot year for two digit year parsing in preference to that stored in the parser.
DateTimeFormatter	withZone(DateTimeZone zone) Returns a new formatter that will use the specified zone in preference to the zone of the printed object, or default zone on a parse.

Methods inherited from class java.lang.Object

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

Constructor Detail

DateTimeFormatter

public DateTimeFormatter(DateTimePrinter printer,
                 DateTimeParser parser)

Creates a new formatter, however you will normally use the factory or the builder.

Parameters:

printer - the internal printer, null if cannot print

parser - the internal parser, null if cannot parse

Method Detail

isPrinter

public boolean isPrinter()

Is this formatter capable of printing.

Returns:

true if this is a printer

getPrinter

public DateTimePrinter getPrinter()

Gets the internal printer object that performs the real printing work.

Returns:

the internal printer; is null if printing not supported

isParser

public boolean isParser()

Is this formatter capable of parsing.

Returns:

true if this is a parser

getParser

public DateTimeParser getParser()

Gets the internal parser object that performs the real parsing work.

Returns:

the internal parser; is null if parsing not supported

withLocale

public DateTimeFormatter withLocale(Locale locale)

Returns a new formatter with a different locale that will be used for printing and parsing.

A DateTimeFormatter is immutable, so a new instance is returned, and the original is unaltered and still usable.

Parameters:

locale - the locale to use; if null, formatter uses default locale at invocation time

Returns:

the new formatter

getLocale

public Locale getLocale()

Gets the locale that will be used for printing and parsing.

Returns:

the locale to use; if null, formatter uses default locale at invocation time

withOffsetParsed

public DateTimeFormatter withOffsetParsed()

Returns a new formatter that will create a datetime with a time zone equal to that of the offset of the parsed string.

After calling this method, a string '2004-06-09T10:20:30-08:00' will create a datetime with a zone of -08:00 (a fixed zone, with no daylight savings rules). If the parsed string represents a local time (no zone offset) the parsed datetime will be in the default zone.

Calling this method sets the override zone to null. Calling the override zone method sets this flag off.

Returns:

the new formatter

isOffsetParsed

public boolean isOffsetParsed()

Checks whether the offset from the string is used as the zone of the parsed datetime.

Returns:

true if the offset from the string is used as the zone

withChronology

public DateTimeFormatter withChronology(Chronology chrono)

Returns a new formatter that will use the specified chronology in preference to that of the printed object, or ISO on a parse.

When printing, this chronolgy will be used in preference to the chronology from the datetime that would otherwise be used.

When parsing, this chronology will be set on the parsed datetime.

A null chronology means no-override. If both an override chronology and an override zone are set, the override zone will take precedence over the zone in the chronology.

Parameters:

chrono - the chronology to use as an override

Returns:

the new formatter

getChronolgy

public Chronology getChronolgy()

Gets the chronology to use as an override.

Returns:

the chronology to use as an override

withZone

public DateTimeFormatter withZone(DateTimeZone zone)

Returns a new formatter that will use the specified zone in preference to the zone of the printed object, or default zone on a parse.

When printing, this zone will be used in preference to the zone from the datetime that would otherwise be used.

When parsing, this zone will be set on the parsed datetime.

A null zone means of no-override. If both an override chronology and an override zone are set, the override zone will take precedence over the zone in the chronology.

Parameters:

zone - the zone to use as an override

Returns:

the new formatter

getZone

public DateTimeZone getZone()

Gets the zone to use as an override.

Returns:

the zone to use as an override

withPivotYear

public DateTimeFormatter withPivotYear(Integer pivotYear)

Returns a new formatter that will use the specified pivot year for two digit year parsing in preference to that stored in the parser.

This setting is useful for changing the pivot year of formats built using a pattern - DateTimeFormat.forPattern(String).

When parsing, this pivot year is used. Null means no-override. There is no effect when printing.

The pivot year enables a two digit year to be converted to a four digit year. The pivot represents the year in the middle of the supported range of years. Thus the full range of years that will be built is (pivot - 50) .. (pivot + 49).

 pivot   supported range   00 is   20 is   40 is   60 is   80 is
 ---------------------------------------------------------------
 1950      1900..1999      1900    1920    1940    1960    1980
 1975      1925..2024      2000    2020    1940    1960    1980
 2000      1950..2049      2000    2020    2040    1960    1980
 2025      1975..2074      2000    2020    2040    2060    1980
 2050      2000..2099      2000    2020    2040    2060    2080
 

Parameters:

pivotYear - the pivot year to use as an override when parsing

Returns:

the new formatter

Since:

1.1

withPivotYear

public DateTimeFormatter withPivotYear(int pivotYear)

Returns a new formatter that will use the specified pivot year for two digit year parsing in preference to that stored in the parser.

This setting is useful for changing the pivot year of formats built using a pattern - DateTimeFormat.forPattern(String).

When parsing, this pivot year is used. There is no effect when printing.

The pivot year enables a two digit year to be converted to a four digit year. The pivot represents the year in the middle of the supported range of years. Thus the full range of years that will be built is (pivot - 50) .. (pivot + 49).

 pivot   supported range   00 is   20 is   40 is   60 is   80 is
 ---------------------------------------------------------------
 1950      1900..1999      1900    1920    1940    1960    1980
 1975      1925..2024      2000    2020    1940    1960    1980
 2000      1950..2049      2000    2020    2040    1960    1980
 2025      1975..2074      2000    2020    2040    2060    1980
 2050      2000..2099      2000    2020    2040    2060    2080
 

Parameters:

pivotYear - the pivot year to use as an override when parsing

Returns:

the new formatter

Since:

1.1

getPivotYear

public Integer getPivotYear()

Gets the pivot year to use as an override.

Returns:

the pivot year to use as an override

Since:

1.1

printTo

public void printTo(StringBuffer buf,
           ReadableInstant instant)

Prints a ReadableInstant, using the chronology supplied by the instant.

Parameters:

buf - formatted instant is appended to this buffer

instant - instant to format, null means now

printTo

public void printTo(StringBuffer buf,
           long instant)

Prints an instant from milliseconds since 1970-01-01T00:00:00Z, using ISO chronology in the default DateTimeZone.

Parameters:

buf - formatted instant is appended to this buffer

instant - millis since 1970-01-01T00:00:00Z

printTo

public void printTo(StringBuffer buf,
           ReadablePartial partial)

Prints a ReadablePartial.

Neither the override chronology nor the override zone are used by this method.

Parameters:

buf - formatted partial is appended to this buffer

partial - partial to format

print

public String print(ReadableInstant instant)

Prints a ReadableInstant to a String.

This method will use the override zone and the override chronololgy if they are set. Otherwise it will use the chronology and zone of the instant.

Parameters:

instant - instant to format, null means now

Returns:

the printed result

print

public String print(long instant)

Prints a millisecond instant to a String.

This method will use the override zone and the override chronololgy if they are set. Otherwise it will use the ISO chronology and default zone.

Parameters:

instant - millis since 1970-01-01T00:00:00Z

Returns:

the printed result

print

public String print(ReadablePartial partial)

Prints a ReadablePartial to a new String.

Neither the override chronology nor the override zone are used by this method.

Parameters:

partial - partial to format

Returns:

the printed result

parseInto

public int parseInto(ReadWritableInstant instant,
            String text,
            int position)

Parses a datetime from the given text, at the given position, saving the result into the fields of the given ReadWritableInstant. If the parse succeeds, the return value is the new text position. Note that the parse may succeed without fully reading the text and in this case those fields that were read will be set.

Only those fields present in the string will be changed in the specified instant. All other fields will remain unaltered. Thus if the string only contains a year and a month, then the day and time will be retained from the input instant. If this is not the behaviour you want, then reset the fields before calling this method, or use parseDateTime(String) or parseMutableDateTime(String).

If it fails, the return value is negative, but the instant may still be modified. To determine the position where the parse failed, apply the one's complement operator (~) on the return value.

The parse will use the chronology of the instant.

Parameters:

instant - an instant that will be modified, not null

text - the text to parse

position - position to start parsing from

Returns:

new position, negative value means parse failed - apply complement operator (~) to get position of failure

Throws:

UnsupportedOperationException - if parsing is not supported

IllegalArgumentException - if the instant is null

IllegalArgumentException - if any field is out of range

parseMillis

public long parseMillis(String text)

Parses a datetime from the given text, returning the number of milliseconds since the epoch, 1970-01-01T00:00:00Z.

The parse will use the ISO chronology, and the default time zone. If the text contains a time zone string then that will be taken into account.

Parameters:

text - text to parse

Returns:

parsed value expressed in milliseconds since the epoch

Throws:

UnsupportedOperationException - if parsing is not supported

IllegalArgumentException - if the text to parse is invalid

parseDateTime

public DateTime parseDateTime(String text)

Parses a datetime from the given text, returning a new DateTime.

The parse will use the zone and chronology specified on this formatter.

If the text contains a time zone string then that will be taken into account in adjusting the time of day as follows. If the withOffsetParsed() has been called, then the resulting DateTime will have a fixed offset based on the parsed time zone. Otherwise the resulting DateTime will have the zone of this formatter, but the parsed zone may have caused the time to be adjusted.

Parameters:

text - the text to parse

Returns:

parsed value in a DateTime object

Throws:

UnsupportedOperationException - if parsing is not supported

IllegalArgumentException - if the text to parse is invalid

parseMutableDateTime

public MutableDateTime parseMutableDateTime(String text)

Parses a datetime from the given text, returning a new MutableDateTime.

The parse will use the zone and chronology specified on this formatter.

If the text contains a time zone string then that will be taken into account in adjusting the time of day as follows. If the withOffsetParsed() has been called, then the resulting DateTime will have a fixed offset based on the parsed time zone. Otherwise the resulting DateTime will have the zone of this formatter, but the parsed zone may have caused the time to be adjusted.

Parameters:

text - the text to parse

Returns:

parsed value in a MutableDateTime object

Throws:

UnsupportedOperationException - if parsing is not supported

IllegalArgumentException - if the text to parse is invalid