- java.lang.Object
-
- java.text.Format
-
- java.text.DateFormat
-
- All Implemented Interfaces:
- Serializable, Cloneable
- Direct Known Subclasses:
- SimpleDateFormat
public abstract class DateFormat extends Format
DateFormat
is an abstract class for date/time formatting subclasses which formats and parses dates or time in a language-independent manner. The date/time formatting subclass, such asSimpleDateFormat
, allows for formatting (i.e., date -> text), parsing (text -> date), and normalization. The date is represented as aDate
object or as the milliseconds since January 1, 1970, 00:00:00 GMT.DateFormat
provides many class methods for obtaining default date/time formatters based on the default or a given locale and a number of formatting styles. The formatting styles includeFULL
,LONG
,MEDIUM
, andSHORT
. More detail and examples of using these styles are provided in the method descriptions.DateFormat
helps you to format and parse dates for any locale. Your code can be completely independent of the locale conventions for months, days of the week, or even the calendar format: lunar vs. solar.To format a date for the current Locale, use one of the static factory methods:
myString = DateFormat.getDateInstance().format(myDate);
If you are formatting multiple dates, it is more efficient to get the format and use it multiple times so that the system doesn't have to fetch the information about the local language and country conventions multiple times.
DateFormat df = DateFormat.getDateInstance(); for (int i = 0; i < myDate.length; ++i) { output.println(df.format(myDate[i]) + "; "); }
To format a date for a different Locale, specify it in the call to
getDateInstance()
.DateFormat df = DateFormat.getDateInstance(DateFormat.LONG, Locale.FRANCE);
You can use a DateFormat to parse also.
myDate = df.parse(myString);
Use
getDateInstance
to get the normal date format for that country. There are other static factory methods available. UsegetTimeInstance
to get the time format for that country. UsegetDateTimeInstance
to get a date and time format. You can pass in different options to these factory methods to control the length of the result; fromSHORT
toMEDIUM
toLONG
toFULL
. The exact result depends on the locale, but generally:SHORT
is completely numeric, such as12.13.52
or3:30pm
MEDIUM
is longer, such asJan 12, 1952
LONG
is longer, such asJanuary 12, 1952
or3:30:32pm
FULL
is pretty completely specified, such asTuesday, April 12, 1952 AD or 3:30:42pm PST
.
You can also set the time zone on the format if you wish. If you want even more control over the format or parsing, (or want to give your users more control), you can try casting the
DateFormat
you get from the factory methods to aSimpleDateFormat
. This will work for the majority of countries; just remember to put it in atry
block in case you encounter an unusual one.You can also use forms of the parse and format methods with
ParsePosition
andFieldPosition
to allow you to- progressively parse through pieces of a string.
- align any particular field, or find out where it is for selection on the screen.
Synchronization
Date formats are not synchronized. It is recommended to create separate format instances for each thread. If multiple threads access a format concurrently, it must be synchronized externally.
- See Also:
Format
,NumberFormat
,SimpleDateFormat
,Calendar
,GregorianCalendar
,TimeZone
, Serialized Form
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Nested Class Summary
Nested Classes Modifier and Type Class and Description static class
DateFormat.Field
Defines constants that are used as attribute keys in theAttributedCharacterIterator
returned fromDateFormat.formatToCharacterIterator
and as field identifiers inFieldPosition
.
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Field Summary
Fields Modifier and Type Field and Description static int
AM_PM_FIELD
Useful constant for AM_PM field alignment.protected Calendar
calendar
TheCalendar
instance used for calculating the date-time fields and the instant of time.static int
DATE_FIELD
Useful constant for DATE field alignment.static int
DAY_OF_WEEK_FIELD
Useful constant for DAY_OF_WEEK field alignment.static int
DAY_OF_WEEK_IN_MONTH_FIELD
Useful constant for DAY_OF_WEEK_IN_MONTH field alignment.static int
DAY_OF_YEAR_FIELD
Useful constant for DAY_OF_YEAR field alignment.static int
DEFAULT
Constant for default style pattern.static int
ERA_FIELD
Useful constant for ERA field alignment.static int
FULL
Constant for full style pattern.static int
HOUR_OF_DAY0_FIELD
Useful constant for zero-based HOUR_OF_DAY field alignment.static int
HOUR_OF_DAY1_FIELD
Useful constant for one-based HOUR_OF_DAY field alignment.static int
HOUR0_FIELD
Useful constant for zero-based HOUR field alignment.static int
HOUR1_FIELD
Useful constant for one-based HOUR field alignment.static int
LONG
Constant for long style pattern.static int
MEDIUM
Constant for medium style pattern.static int
MILLISECOND_FIELD
Useful constant for MILLISECOND field alignment.static int
MINUTE_FIELD
Useful constant for MINUTE field alignment.static int
MONTH_FIELD
Useful constant for MONTH field alignment.protected NumberFormat
numberFormat
The number formatter thatDateFormat
uses to format numbers in dates and times.static int
SECOND_FIELD
Useful constant for SECOND field alignment.static int
SHORT
Constant for short style pattern.static int
TIMEZONE_FIELD
Useful constant for TIMEZONE field alignment.static int
WEEK_OF_MONTH_FIELD
Useful constant for WEEK_OF_MONTH field alignment.static int
WEEK_OF_YEAR_FIELD
Useful constant for WEEK_OF_YEAR field alignment.static int
YEAR_FIELD
Useful constant for YEAR field alignment.
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Constructor Summary
Constructors Modifier Constructor and Description protected
DateFormat()
Create a new date format.
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Method Summary
Methods Modifier and Type Method and Description Object
clone()
Overrides Cloneableboolean
equals(Object obj)
Overrides equalsString
format(Date date)
Formats a Date into a date/time string.abstract StringBuffer
format(Date date, StringBuffer toAppendTo, FieldPosition fieldPosition)
Formats a Date into a date/time string.StringBuffer
format(Object obj, StringBuffer toAppendTo, FieldPosition fieldPosition)
Overrides Format.static Locale[]
getAvailableLocales()
Returns an array of all locales for which theget*Instance
methods of this class can return localized instances.Calendar
getCalendar()
Gets the calendar associated with this date/time formatter.static DateFormat
getDateInstance()
Gets the date formatter with the default formatting style for the default locale.static DateFormat
getDateInstance(int style)
Gets the date formatter with the given formatting style for the default locale.static DateFormat
getDateInstance(int style, Locale aLocale)
Gets the date formatter with the given formatting style for the given locale.static DateFormat
getDateTimeInstance()
Gets the date/time formatter with the default formatting style for the default locale.static DateFormat
getDateTimeInstance(int dateStyle, int timeStyle)
Gets the date/time formatter with the given date and time formatting styles for the default locale.static DateFormat
getDateTimeInstance(int dateStyle, int timeStyle, Locale aLocale)
Gets the date/time formatter with the given formatting styles for the given locale.static DateFormat
getInstance()
Get a default date/time formatter that uses the SHORT style for both the date and the time.NumberFormat
getNumberFormat()
Gets the number formatter which this date/time formatter uses to format and parse a time.static DateFormat
getTimeInstance()
Gets the time formatter with the default formatting style for the default locale.static DateFormat
getTimeInstance(int style)
Gets the time formatter with the given formatting style for the default locale.static DateFormat
getTimeInstance(int style, Locale aLocale)
Gets the time formatter with the given formatting style for the given locale.TimeZone
getTimeZone()
Gets the time zone.int
hashCode()
Overrides hashCodeboolean
isLenient()
Tell whether date/time parsing is to be lenient.Date
parse(String source)
Parses text from the beginning of the given string to produce a date.abstract Date
parse(String source, ParsePosition pos)
Parse a date/time string according to the given parse position.Object
parseObject(String source, ParsePosition pos)
Parses text from a string to produce aDate
.void
setCalendar(Calendar newCalendar)
Set the calendar to be used by this date format.void
setLenient(boolean lenient)
Specify whether or not date/time parsing is to be lenient.void
setNumberFormat(NumberFormat newNumberFormat)
Allows you to set the number formatter.void
setTimeZone(TimeZone zone)
Sets the time zone for the calendar of thisDateFormat
object.-
Methods inherited from class java.text.Format
format, formatToCharacterIterator, parseObject
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Field Detail
-
calendar
protected Calendar calendar
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numberFormat
protected NumberFormat numberFormat
The number formatter thatDateFormat
uses to format numbers in dates and times. Subclasses should initialize this to a number format appropriate for the locale associated with thisDateFormat
.
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ERA_FIELD
public static final int ERA_FIELD
Useful constant for ERA field alignment. Used in FieldPosition of date/time formatting.- See Also:
- Constant Field Values
-
YEAR_FIELD
public static final int YEAR_FIELD
Useful constant for YEAR field alignment. Used in FieldPosition of date/time formatting.- See Also:
- Constant Field Values
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MONTH_FIELD
public static final int MONTH_FIELD
Useful constant for MONTH field alignment. Used in FieldPosition of date/time formatting.- See Also:
- Constant Field Values
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DATE_FIELD
public static final int DATE_FIELD
Useful constant for DATE field alignment. Used in FieldPosition of date/time formatting.- See Also:
- Constant Field Values
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HOUR_OF_DAY1_FIELD
public static final int HOUR_OF_DAY1_FIELD
Useful constant for one-based HOUR_OF_DAY field alignment. Used in FieldPosition of date/time formatting. HOUR_OF_DAY1_FIELD is used for the one-based 24-hour clock. For example, 23:59 + 01:00 results in 24:59.- See Also:
- Constant Field Values
-
HOUR_OF_DAY0_FIELD
public static final int HOUR_OF_DAY0_FIELD
Useful constant for zero-based HOUR_OF_DAY field alignment. Used in FieldPosition of date/time formatting. HOUR_OF_DAY0_FIELD is used for the zero-based 24-hour clock. For example, 23:59 + 01:00 results in 00:59.- See Also:
- Constant Field Values
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MINUTE_FIELD
public static final int MINUTE_FIELD
Useful constant for MINUTE field alignment. Used in FieldPosition of date/time formatting.- See Also:
- Constant Field Values
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SECOND_FIELD
public static final int SECOND_FIELD
Useful constant for SECOND field alignment. Used in FieldPosition of date/time formatting.- See Also:
- Constant Field Values
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MILLISECOND_FIELD
public static final int MILLISECOND_FIELD
Useful constant for MILLISECOND field alignment. Used in FieldPosition of date/time formatting.- See Also:
- Constant Field Values
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DAY_OF_WEEK_FIELD
public static final int DAY_OF_WEEK_FIELD
Useful constant for DAY_OF_WEEK field alignment. Used in FieldPosition of date/time formatting.- See Also:
- Constant Field Values
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DAY_OF_YEAR_FIELD
public static final int DAY_OF_YEAR_FIELD
Useful constant for DAY_OF_YEAR field alignment. Used in FieldPosition of date/time formatting.- See Also:
- Constant Field Values
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DAY_OF_WEEK_IN_MONTH_FIELD
public static final int DAY_OF_WEEK_IN_MONTH_FIELD
Useful constant for DAY_OF_WEEK_IN_MONTH field alignment. Used in FieldPosition of date/time formatting.- See Also:
- Constant Field Values
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WEEK_OF_YEAR_FIELD
public static final int WEEK_OF_YEAR_FIELD
Useful constant for WEEK_OF_YEAR field alignment. Used in FieldPosition of date/time formatting.- See Also:
- Constant Field Values
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WEEK_OF_MONTH_FIELD
public static final int WEEK_OF_MONTH_FIELD
Useful constant for WEEK_OF_MONTH field alignment. Used in FieldPosition of date/time formatting.- See Also:
- Constant Field Values
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AM_PM_FIELD
public static final int AM_PM_FIELD
Useful constant for AM_PM field alignment. Used in FieldPosition of date/time formatting.- See Also:
- Constant Field Values
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HOUR1_FIELD
public static final int HOUR1_FIELD
Useful constant for one-based HOUR field alignment. Used in FieldPosition of date/time formatting. HOUR1_FIELD is used for the one-based 12-hour clock. For example, 11:30 PM + 1 hour results in 12:30 AM.- See Also:
- Constant Field Values
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HOUR0_FIELD
public static final int HOUR0_FIELD
Useful constant for zero-based HOUR field alignment. Used in FieldPosition of date/time formatting. HOUR0_FIELD is used for the zero-based 12-hour clock. For example, 11:30 PM + 1 hour results in 00:30 AM.- See Also:
- Constant Field Values
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TIMEZONE_FIELD
public static final int TIMEZONE_FIELD
Useful constant for TIMEZONE field alignment. Used in FieldPosition of date/time formatting.- See Also:
- Constant Field Values
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FULL
public static final int FULL
Constant for full style pattern.- See Also:
- Constant Field Values
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LONG
public static final int LONG
Constant for long style pattern.- See Also:
- Constant Field Values
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MEDIUM
public static final int MEDIUM
Constant for medium style pattern.- See Also:
- Constant Field Values
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SHORT
public static final int SHORT
Constant for short style pattern.- See Also:
- Constant Field Values
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DEFAULT
public static final int DEFAULT
Constant for default style pattern. Its value is MEDIUM.- See Also:
- Constant Field Values
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Method Detail
-
format
public final StringBuffer format(Object obj, StringBuffer toAppendTo, FieldPosition fieldPosition)
Overrides Format. Formats a time object into a time string. Examples of time objects are a time value expressed in milliseconds and a Date object.- Specified by:
format
in classFormat
- Parameters:
obj
- must be a Number or a Date.toAppendTo
- the string buffer for the returning time string.fieldPosition
- keeps track of the position of the field within the returned string. On input: an alignment field, if desired. On output: the offsets of the alignment field. For example, given a time text "1996.07.10 AD at 15:08:56 PDT", if the given fieldPosition is DateFormat.YEAR_FIELD, the begin index and end index of fieldPosition will be set to 0 and 4, respectively. Notice that if the same time field appears more than once in a pattern, the fieldPosition will be set for the first occurrence of that time field. For instance, formatting a Date to the time string "1 PM PDT (Pacific Daylight Time)" using the pattern "h a z (zzzz)" and the alignment field DateFormat.TIMEZONE_FIELD, the begin index and end index of fieldPosition will be set to 5 and 8, respectively, for the first occurrence of the timezone pattern character 'z'.- Returns:
- the string buffer passed in as toAppendTo, with formatted text appended.
- See Also:
Format
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format
public abstract StringBuffer format(Date date, StringBuffer toAppendTo, FieldPosition fieldPosition)
Formats a Date into a date/time string.- Parameters:
date
- a Date to be formatted into a date/time string.toAppendTo
- the string buffer for the returning date/time string.fieldPosition
- keeps track of the position of the field within the returned string. On input: an alignment field, if desired. On output: the offsets of the alignment field. For example, given a time text "1996.07.10 AD at 15:08:56 PDT", if the given fieldPosition is DateFormat.YEAR_FIELD, the begin index and end index of fieldPosition will be set to 0 and 4, respectively. Notice that if the same time field appears more than once in a pattern, the fieldPosition will be set for the first occurrence of that time field. For instance, formatting a Date to the time string "1 PM PDT (Pacific Daylight Time)" using the pattern "h a z (zzzz)" and the alignment field DateFormat.TIMEZONE_FIELD, the begin index and end index of fieldPosition will be set to 5 and 8, respectively, for the first occurrence of the timezone pattern character 'z'.- Returns:
- the string buffer passed in as toAppendTo, with formatted text appended.
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format
public final String format(Date date)
Formats a Date into a date/time string.- Parameters:
date
- the time value to be formatted into a time string.- Returns:
- the formatted time string.
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parse
public Date parse(String source) throws ParseException
Parses text from the beginning of the given string to produce a date. The method may not use the entire text of the given string.See the
parse(String, ParsePosition)
method for more information on date parsing.- Parameters:
source
- AString
whose beginning should be parsed.- Returns:
- A
Date
parsed from the string. - Throws:
ParseException
- if the beginning of the specified string cannot be parsed.
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parse
public abstract Date parse(String source, ParsePosition pos)
Parse a date/time string according to the given parse position. For example, a time text"07/10/96 4:5 PM, PDT"
will be parsed into aDate
that is equivalent toDate(837039900000L)
.By default, parsing is lenient: If the input is not in the form used by this object's format method but can still be parsed as a date, then the parse succeeds. Clients may insist on strict adherence to the format by calling
setLenient(false)
.This parsing operation uses the
calendar
to produce aDate
. As a result, thecalendar
's date-time fields and theTimeZone
value may have been overwritten, depending on subclass implementations. AnyTimeZone
value that has previously been set by a call tosetTimeZone
may need to be restored for further operations.- Parameters:
source
- The date/time string to be parsedpos
- On input, the position at which to start parsing; on output, the position at which parsing terminated, or the start position if the parse failed.- Returns:
- A
Date
, ornull
if the input could not be parsed
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parseObject
public Object parseObject(String source, ParsePosition pos)
Parses text from a string to produce aDate
.The method attempts to parse text starting at the index given by
pos
. If parsing succeeds, then the index ofpos
is updated to the index after the last character used (parsing does not necessarily use all characters up to the end of the string), and the parsed date is returned. The updatedpos
can be used to indicate the starting point for the next call to this method. If an error occurs, then the index ofpos
is not changed, the error index ofpos
is set to the index of the character where the error occurred, and null is returned.See the
parse(String, ParsePosition)
method for more information on date parsing.- Specified by:
parseObject
in classFormat
- Parameters:
source
- AString
, part of which should be parsed.pos
- AParsePosition
object with index and error index information as described above.- Returns:
- A
Date
parsed from the string. In case of error, returns null. - Throws:
NullPointerException
- ifpos
is null.
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getTimeInstance
public static final DateFormat getTimeInstance()
Gets the time formatter with the default formatting style for the default locale.- Returns:
- a time formatter.
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getTimeInstance
public static final DateFormat getTimeInstance(int style)
Gets the time formatter with the given formatting style for the default locale.- Parameters:
style
- the given formatting style. For example, SHORT for "h:mm a" in the US locale.- Returns:
- a time formatter.
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getTimeInstance
public static final DateFormat getTimeInstance(int style, Locale aLocale)
Gets the time formatter with the given formatting style for the given locale.- Parameters:
style
- the given formatting style. For example, SHORT for "h:mm a" in the US locale.aLocale
- the given locale.- Returns:
- a time formatter.
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getDateInstance
public static final DateFormat getDateInstance()
Gets the date formatter with the default formatting style for the default locale.- Returns:
- a date formatter.
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getDateInstance
public static final DateFormat getDateInstance(int style)
Gets the date formatter with the given formatting style for the default locale.- Parameters:
style
- the given formatting style. For example, SHORT for "M/d/yy" in the US locale.- Returns:
- a date formatter.
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getDateInstance
public static final DateFormat getDateInstance(int style, Locale aLocale)
Gets the date formatter with the given formatting style for the given locale.- Parameters:
style
- the given formatting style. For example, SHORT for "M/d/yy" in the US locale.aLocale
- the given locale.- Returns:
- a date formatter.
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getDateTimeInstance
public static final DateFormat getDateTimeInstance()
Gets the date/time formatter with the default formatting style for the default locale.- Returns:
- a date/time formatter.
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getDateTimeInstance
public static final DateFormat getDateTimeInstance(int dateStyle, int timeStyle)
Gets the date/time formatter with the given date and time formatting styles for the default locale.- Parameters:
dateStyle
- the given date formatting style. For example, SHORT for "M/d/yy" in the US locale.timeStyle
- the given time formatting style. For example, SHORT for "h:mm a" in the US locale.- Returns:
- a date/time formatter.
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getDateTimeInstance
public static final DateFormat getDateTimeInstance(int dateStyle, int timeStyle, Locale aLocale)
Gets the date/time formatter with the given formatting styles for the given locale.- Parameters:
dateStyle
- the given date formatting style.timeStyle
- the given time formatting style.aLocale
- the given locale.- Returns:
- a date/time formatter.
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getInstance
public static final DateFormat getInstance()
Get a default date/time formatter that uses the SHORT style for both the date and the time.
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getAvailableLocales
public static Locale[] getAvailableLocales()
Returns an array of all locales for which theget*Instance
methods of this class can return localized instances. The returned array represents the union of locales supported by the Java runtime and by installedDateFormatProvider
implementations. It must contain at least aLocale
instance equal toLocale.US
.- Returns:
- An array of locales for which localized
DateFormat
instances are available.
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setCalendar
public void setCalendar(Calendar newCalendar)
Set the calendar to be used by this date format. Initially, the default calendar for the specified or default locale is used.Any
TimeZone
and leniency values that have previously been set are overwritten bynewCalendar
's values.- Parameters:
newCalendar
- the newCalendar
to be used by the date format
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getCalendar
public Calendar getCalendar()
Gets the calendar associated with this date/time formatter.- Returns:
- the calendar associated with this date/time formatter.
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setNumberFormat
public void setNumberFormat(NumberFormat newNumberFormat)
Allows you to set the number formatter.- Parameters:
newNumberFormat
- the given new NumberFormat.
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getNumberFormat
public NumberFormat getNumberFormat()
Gets the number formatter which this date/time formatter uses to format and parse a time.- Returns:
- the number formatter which this date/time formatter uses.
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setTimeZone
public void setTimeZone(TimeZone zone)
Sets the time zone for the calendar of thisDateFormat
object. This method is equivalent to the following call.getCalendar().setTimeZone(zone)
The
TimeZone
set by this method is overwritten by asetCalendar
call.The
TimeZone
set by this method may be overwritten as a result of a call to the parse method.- Parameters:
zone
- the given new time zone.
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getTimeZone
public TimeZone getTimeZone()
Gets the time zone. This method is equivalent to the following call.getCalendar().getTimeZone()
- Returns:
- the time zone associated with the calendar of DateFormat.
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setLenient
public void setLenient(boolean lenient)
Specify whether or not date/time parsing is to be lenient. With lenient parsing, the parser may use heuristics to interpret inputs that do not precisely match this object's format. With strict parsing, inputs must match this object's format.This method is equivalent to the following call.
getCalendar().setLenient(lenient)
This leniency value is overwritten by a call to
setCalendar()
.- Parameters:
lenient
- whentrue
, parsing is lenient- See Also:
Calendar.setLenient(boolean)
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isLenient
public boolean isLenient()
Tell whether date/time parsing is to be lenient. This method is equivalent to the following call.getCalendar().isLenient()
- Returns:
true
if thecalendar
is lenient;false
otherwise.- See Also:
Calendar.isLenient()
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hashCode
public int hashCode()
Overrides hashCode- Overrides:
hashCode
in classObject
- Returns:
- a hash code value for this object.
- See Also:
Object.equals(java.lang.Object)
,System.identityHashCode(java.lang.Object)
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equals
public boolean equals(Object obj)
Overrides equals- Overrides:
equals
in classObject
- Parameters:
obj
- the reference object with which to compare.- Returns:
true
if this object is the same as the obj argument;false
otherwise.- See Also:
Object.hashCode()
,HashMap
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Bij voorbaat dank.
Document heeft de 11/06/2005 gemaakt, de laatste keer de 04/03/2020 gewijzigd
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