Class MessageFormat
- All Implemented Interfaces:
Serializable
,Cloneable
MessageFormat prepares strings for display to users, with optional arguments (variables/placeholders). The arguments can occur in any order, which is necessary for translation into languages with different grammars.
A MessageFormat is constructed from a pattern string with arguments in {curly braces} which will be replaced by formatted values.
MessageFormat
differs from the other Format
classes in that you create a MessageFormat
object with one
of its constructors (not with a getInstance
style factory
method). Factory methods aren't necessary because MessageFormat
itself doesn't implement locale-specific behavior. Any locale-specific
behavior is defined by the pattern that you provide and the
subformats used for inserted arguments.
Arguments can be named (using identifiers) or numbered (using small ASCII-digit integers).
Some of the API methods work only with argument numbers and throw an exception
if the pattern has named arguments (see usesNamedArguments()
).
An argument might not specify any format type. In this case, a Number value is formatted with a default (for the locale) NumberFormat, a Date value is formatted with a default (for the locale) DateFormat, and for any other value its toString() value is used.
An argument might specify a "simple" type for which the specified Format object is created, cached and used.
An argument might have a "complex" type with nested MessageFormat sub-patterns. During formatting, one of these sub-messages is selected according to the argument value and recursively formatted.
After construction, a custom Format object can be set for a top-level argument, overriding the default formatting and parsing behavior for that argument. However, custom formatting can be achieved more simply by writing a typeless argument in the pattern string and supplying it with a preformatted string value.
When formatting, MessageFormat takes a collection of argument values and writes an output string. The argument values may be passed as an array (when the pattern contains only numbered arguments) or as a Map (which works for both named and numbered arguments).
Each argument is matched with one of the input values by array index or map key and formatted according to its pattern specification (or using a custom Format object if one was set). A numbered pattern argument is matched with a map key that contains that number as an ASCII-decimal-digit string (without leading zero).
Patterns and Their Interpretation
MessageFormat
uses patterns of the following form:
message = messageText (argument messageText)* argument = noneArg | simpleArg | complexArg complexArg = choiceArg | pluralArg | selectArg | selectordinalArg noneArg = '{' argNameOrNumber '}' simpleArg = '{' argNameOrNumber ',' argType [',' argStyle] '}' choiceArg = '{' argNameOrNumber ',' "choice" ',' choiceStyle '}' pluralArg = '{' argNameOrNumber ',' "plural" ',' pluralStyle '}' selectArg = '{' argNameOrNumber ',' "select" ',' selectStyle '}' selectordinalArg = '{' argNameOrNumber ',' "selectordinal" ',' pluralStyle '}' choiceStyle: seeChoiceFormat
pluralStyle: seePluralFormat
selectStyle: seeSelectFormat
argNameOrNumber = argName | argNumber argName = [^[[:Pattern_Syntax:][:Pattern_White_Space:]]]+ argNumber = '0' | ('1'..'9' ('0'..'9')*) argType = "number" | "date" | "time" | "spellout" | "ordinal" | "duration" argStyle = "short" | "medium" | "long" | "full" | "integer" | "currency" | "percent" | argStyleText | "::" argSkeletonText
- messageText can contain quoted literal strings including syntax characters. A quoted literal string begins with an ASCII apostrophe and a syntax character (usually a {curly brace}) and continues until the next single apostrophe. A double ASCII apostrophe inside or outside of a quoted string represents one literal apostrophe.
- Quotable syntax characters are the {curly braces} in all messageText parts, plus the '#' sign in a messageText immediately inside a pluralStyle, and the '|' symbol in a messageText immediately inside a choiceStyle.
- See also
MessagePattern.ApostropheMode
- In argStyleText, every single ASCII apostrophe begins and ends quoted literal text, and unquoted {curly braces} must occur in matched pairs.
Recommendation: Use the real apostrophe (single quote) character \\u2019 for human-readable text, and use the ASCII apostrophe (\\u0027 ' ) only in program syntax, like quoting in MessageFormat. See the annotations for U+0027 Apostrophe in The Unicode Standard.
The choice
argument type is deprecated.
Use plural
arguments for proper plural selection,
and select
arguments for simple selection among a fixed set of choices.
The argType
and argStyle
values are used to create
a Format
instance for the format element. The following
table shows how the values map to Format instances. Combinations not
shown in the table are illegal. Any argStyleText
must
be a valid pattern string for the Format subclass used.
argType | argStyle | resulting Format object |
---|---|---|
(none) | null
| |
number
| (none) | NumberFormat.getInstance(getLocale())
|
integer
| NumberFormat.getIntegerInstance(getLocale())
| |
currency
| NumberFormat.getCurrencyInstance(getLocale())
| |
percent
| NumberFormat.getPercentInstance(getLocale())
| |
argStyleText | new DecimalFormat(argStyleText, new DecimalFormatSymbols(getLocale()))
| |
argSkeletonText | NumberFormatter.forSkeleton(argSkeletonText).locale(getLocale()).toFormat()
| |
date
| (none) | DateFormat.getDateInstance(DateFormat.DEFAULT, getLocale())
|
short
| DateFormat.getDateInstance(DateFormat.SHORT, getLocale())
| |
medium
| DateFormat.getDateInstance(DateFormat.DEFAULT, getLocale())
| |
long
| DateFormat.getDateInstance(DateFormat.LONG, getLocale())
| |
full
| DateFormat.getDateInstance(DateFormat.FULL, getLocale())
| |
argStyleText | new SimpleDateFormat(argStyleText, getLocale())
| |
argSkeletonText | DateFormat.getInstanceForSkeleton(argSkeletonText, getLocale())
| |
time
| (none) | DateFormat.getTimeInstance(DateFormat.DEFAULT, getLocale())
|
short
| DateFormat.getTimeInstance(DateFormat.SHORT, getLocale())
| |
medium
| DateFormat.getTimeInstance(DateFormat.DEFAULT, getLocale())
| |
long
| DateFormat.getTimeInstance(DateFormat.LONG, getLocale())
| |
full
| DateFormat.getTimeInstance(DateFormat.FULL, getLocale())
| |
argStyleText | new SimpleDateFormat(argStyleText, getLocale())
| |
spellout
| argStyleText (optional) | new RuleBasedNumberFormat(getLocale(), RuleBasedNumberFormat.SPELLOUT)
|
ordinal
| argStyleText (optional) | new RuleBasedNumberFormat(getLocale(), RuleBasedNumberFormat.ORDINAL)
|
duration
| argStyleText (optional) | new RuleBasedNumberFormat(getLocale(), RuleBasedNumberFormat.DURATION)
|
Differences from java.text.MessageFormat
The ICU MessageFormat supports both named and numbered arguments, while the JDK MessageFormat only supports numbered arguments. Named arguments make patterns more readable.
ICU implements a more user-friendly apostrophe quoting syntax.
In message text, an apostrophe only begins quoting literal text
if it immediately precedes a syntax character (mostly {curly braces}).
In the JDK MessageFormat, an apostrophe always begins quoting,
which requires common text like "don't" and "aujourd'hui"
to be written with doubled apostrophes like "don''t" and "aujourd''hui".
For more details see MessagePattern.ApostropheMode
.
ICU does not create a ChoiceFormat object for a choiceArg, pluralArg or selectArg
but rather handles such arguments itself.
The JDK MessageFormat does create and use a ChoiceFormat object
(new ChoiceFormat(argStyleText)
).
The JDK does not support plural and select arguments at all.
Both the ICU and the JDK MessageFormat
can control the argument
formats by using argStyle
. But the JDK MessageFormat
only
supports predefined formats and number / date / time pattern strings (which would need
to be localized).
ICU supports everything the JDK does, and also number / date / time skeletons using the
::
prefix (which automatically yield output appropriate for the
MessageFormat
locale).
Argument formatting
Arguments are formatted according to their type, using the default
ICU formatters for those types, unless otherwise specified.
For unknown types, MessageFormat
will call toString()
.
There are also several ways to control the formatting.
We recommend you use default styles, predefined style values, skeletons, or preformatted values, but not pattern strings or custom format objects.
For more details, see the ICU User Guide.
Usage Information
Here are some examples of usage:
Typically, the message format will come from resources, and the arguments will be dynamically set at runtime.Object[] arguments = { 7, new Date(System.currentTimeMillis()), "a disturbance in the Force" }; String result = MessageFormat.format( "At {1,time,::jmm} on {1,date,::dMMMM}, there was {2} on planet {0,number,integer}.", arguments); output: At 4:34 PM on March 23, there was a disturbance in the Force on planet 7.
Example 2:
Object[] testArgs = { 3, "MyDisk" }; MessageFormat form = new MessageFormat( "The disk \"{1}\" contains {0} file(s)."); System.out.println(form.format(testArgs)); // output, with different testArgs output: The disk "MyDisk" contains 0 file(s). output: The disk "MyDisk" contains 1 file(s). output: The disk "MyDisk" contains 1,273 file(s).
For messages that include plural forms, you can use a plural argument:
MessageFormat msgFmt = new MessageFormat( "{num_files, plural, " + "=0{There are no files on disk \"{disk_name}\".}" + "=1{There is one file on disk \"{disk_name}\".}" + "other{There are # files on disk \"{disk_name}\".}}", ULocale.ENGLISH); Map args = new HashMap(); args.put("num_files", 0); args.put("disk_name", "MyDisk"); System.out.println(msgFmt.format(args)); args.put("num_files", 3); System.out.println(msgFmt.format(args)); output: There are no files on disk "MyDisk". There are 3 files on "MyDisk".See
PluralFormat
and PluralRules
for details.
Synchronization
MessageFormats 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.
-
Nested Class Summary
Nested ClassesModifier and TypeClassDescriptionprivate static final class
Convenience wrapper for Appendable, tracks the result string length.private static final class
static class
Defines constants that are used as attribute keys in theAttributedCharacterIterator
returned fromMessageFormat.formatToCharacterIterator
.private static final class
Mutable input/output values for the PluralSelectorProvider.private static final class
This provider helps defer instantiation of a PluralRules object until we actually need to select a keyword.Nested classes/interfaces inherited from class com.ibm.icu.text.UFormat
UFormat.SpanField
-
Field Summary
FieldsModifier and TypeFieldDescriptionCached formatters so we can just use them whenever needed instead of creating them from scratch every time.private static final char
private static final char
Set of ARG_START part indexes where custom, user-provided Format objects have been set via setFormat() or similar API.private static final int
private static final int
private static final int
private static final int
private static final int
private static final String[]
private static final int
private static final int
private static final int
private static final int
private static final String[]
private MessagePattern
The MessagePattern which contains the parsed structure of the pattern string.private static final Locale
(package private) static final long
private static final char
private static final int
private static final int
private static final int
private static final int
private DateFormat
Stock formatters.private NumberFormat
private static final int
private static final int
private static final int
private static final int
private static final int
private static final int
private static final String[]
private ULocale
The locale to use for formatting numbers and dates. -
Constructor Summary
ConstructorsConstructorDescriptionMessageFormat
(String pattern) Constructs a MessageFormat for the defaultFORMAT
locale and the specified pattern.MessageFormat
(String pattern, ULocale locale) Constructs a MessageFormat for the specified locale and pattern.MessageFormat
(String pattern, Locale locale) Constructs a MessageFormat for the specified locale and pattern. -
Method Summary
Modifier and TypeMethodDescriptionvoid
applyPattern
(String pttrn) Sets the pattern used by this message format.void
applyPattern
(String pattern, MessagePattern.ApostropheMode aposMode) Sets the ApostropheMode and the pattern used by this message format.private boolean
argNameMatches
(int partIndex, String argName, int argNumber) static String
autoQuoteApostrophe
(String pattern) Converts an 'apostrophe-friendly' pattern into a standard pattern.private void
clone()
private Format
createAppropriateFormat
(String type, String style) (package private) Format
boolean
private static int
findChoiceSubMessage
(MessagePattern pattern, int partIndex, double number) Finds the ChoiceFormat sub-message for the given number.private int
findFirstPluralNumberArg
(int msgStart, String argName) Returns the ARG_START index of the first occurrence of the plural number in a sub-message.private static final int
findKeyword
(String s, String[] list) private int
findOtherSubMessage
(int partIndex) Finds the "other" sub-message.private void
format
(int msgStart, MessageFormat.PluralSelectorContext pluralNumber, Object[] args, Map<String, Object> argsMap, MessageFormat.AppendableWrapper dest, FieldPosition fp) Formats the arguments and writes the result into the AppendableWrapper, updates the field position.final StringBuffer
format
(Object[] arguments, StringBuffer result, FieldPosition pos) Formats an array of objects and appends theMessageFormat
's pattern, with arguments replaced by the formatted objects, to the providedStringBuffer
.private void
format
(Object[] arguments, Map<String, Object> argsMap, MessageFormat.AppendableWrapper dest, FieldPosition fp) Internal routine used by format.private void
format
(Object arguments, MessageFormat.AppendableWrapper result, FieldPosition fp) final StringBuffer
format
(Object arguments, StringBuffer result, FieldPosition pos) Formats a map or array of objects and appends theMessageFormat
's pattern, with format elements replaced by the formatted objects, to the providedStringBuffer
.static String
Creates a MessageFormat with the given pattern and uses it to format the given arguments.static String
Creates a MessageFormat with the given pattern and uses it to format the given arguments.final StringBuffer
format
(Map<String, Object> arguments, StringBuffer result, FieldPosition pos) Formats a map of objects and appends theMessageFormat
's pattern, with arguments replaced by the formatted objects, to the providedStringBuffer
.private void
formatComplexSubMessage
(int msgStart, MessageFormat.PluralSelectorContext pluralNumber, Object[] args, Map<String, Object> argsMap, MessageFormat.AppendableWrapper dest) formatToCharacterIterator
(Object arguments) Formats an array of objects and inserts them into theMessageFormat
's pattern, producing anAttributedCharacterIterator
.private String
getArgName
(int partIndex) Returns the top-level argument names.getFormatByArgumentName
(String argumentName) Returns the first top-level format associated with the given argument name.Format[]
Returns the Format objects used for the format elements in the previously set pattern string.Format[]
Returns the Format objects used for the values passed intoformat
methods or returned fromparse
methods.private String
getLiteralStringUntilNextArgument
(int from) Read as much literal string from the pattern string as possible.Returns the locale that's used when creating or comparing subformats.private DateFormat
private NumberFormat
Returns the locale that's used when creating argument Format objects.int
hashCode()
private static int
matchStringUntilLimitPart
(MessagePattern pattern, int partIndex, int limitPartIndex, String source, int sourceOffset) Matches the pattern string from the end of the partIndex to the beginning of the limitPartIndex, including all syntax except SKIP_SYNTAX, against the source string starting at sourceOffset.private int
nextTopLevelArgStart
(int partIndex) Returns the part index of the next ARG_START after partIndex, or -1 if there is none more.private void
Parses the string, filling either the Map or the Array.Object[]
Parses text from the beginning of the given string to produce an object array.Object[]
parse
(String source, ParsePosition pos) Parses the string.private static double
parseChoiceArgument
(MessagePattern pattern, int partIndex, String source, ParsePosition pos) parseObject
(String source, ParsePosition pos) Parses text from a string to produce an object array or Map.parseToMap
(String source) Parses text from the beginning of the given string to produce a map from argument to values.parseToMap
(String source, ParsePosition pos) Parses the string, returning the results in a Map.private void
Custom deserialization, new in ICU 4.8.private void
private void
setArgStartFormat
(int argStart, Format formatter) Sets a formatter for a MessagePattern ARG_START part index.private void
setCustomArgStartFormat
(int argStart, Format formatter) Sets a custom formatter for a MessagePattern ARG_START part index.void
Sets the Format object to use for the format element with the given format element index within the previously set pattern string.void
setFormatByArgumentIndex
(int argumentIndex, Format newFormat) Sets the Format object to use for the format elements within the previously set pattern string that use the given argument index.void
setFormatByArgumentName
(String argumentName, Format newFormat) Sets the Format object to use for the format elements within the previously set pattern string that use the given argument name.void
setFormats
(Format[] newFormats) Sets the Format objects to use for the format elements in the previously set pattern string.void
setFormatsByArgumentIndex
(Format[] newFormats) Sets the Format objects to use for the values passed intoformat
methods or returned fromparse
methods.void
setFormatsByArgumentName
(Map<String, Format> newFormats) Sets the Format objects to use for the values passed intoformat
methods or returned fromparse
methods.void
Sets the locale to be used for creating argument Format objects.void
Sets the locale to be used for creating argument Format objects.Returns the applied pattern string.private FieldPosition
updateMetaData
(MessageFormat.AppendableWrapper dest, int prevLength, FieldPosition fp, Object argId) boolean
Returns true if this MessageFormat uses named arguments, and false otherwise.private void
Custom serialization, new in ICU 4.8.Methods inherited from class java.text.Format
format, parseObject
-
Field Details
-
serialVersionUID
static final long serialVersionUID- See Also:
-
ulocale
The locale to use for formatting numbers and dates. -
msgPattern
The MessagePattern which contains the parsed structure of the pattern string. -
cachedFormatters
Cached formatters so we can just use them whenever needed instead of creating them from scratch every time. -
customFormatArgStarts
Set of ARG_START part indexes where custom, user-provided Format objects have been set via setFormat() or similar API. -
stockDateFormatter
Stock formatters. Those are used when a format is not explicitly mentioned in the message. The format is inferred from the argument. -
stockNumberFormatter
-
pluralProvider
-
ordinalProvider
-
typeList
-
TYPE_NUMBER
private static final int TYPE_NUMBER- See Also:
-
TYPE_DATE
private static final int TYPE_DATE- See Also:
-
TYPE_TIME
private static final int TYPE_TIME- See Also:
-
TYPE_SPELLOUT
private static final int TYPE_SPELLOUT- See Also:
-
TYPE_ORDINAL
private static final int TYPE_ORDINAL- See Also:
-
TYPE_DURATION
private static final int TYPE_DURATION- See Also:
-
modifierList
-
MODIFIER_EMPTY
private static final int MODIFIER_EMPTY- See Also:
-
MODIFIER_CURRENCY
private static final int MODIFIER_CURRENCY- See Also:
-
MODIFIER_PERCENT
private static final int MODIFIER_PERCENT- See Also:
-
MODIFIER_INTEGER
private static final int MODIFIER_INTEGER- See Also:
-
dateModifierList
-
DATE_MODIFIER_EMPTY
private static final int DATE_MODIFIER_EMPTY- See Also:
-
DATE_MODIFIER_SHORT
private static final int DATE_MODIFIER_SHORT- See Also:
-
DATE_MODIFIER_MEDIUM
private static final int DATE_MODIFIER_MEDIUM- See Also:
-
DATE_MODIFIER_LONG
private static final int DATE_MODIFIER_LONG- See Also:
-
DATE_MODIFIER_FULL
private static final int DATE_MODIFIER_FULL- See Also:
-
rootLocale
-
SINGLE_QUOTE
private static final char SINGLE_QUOTE- See Also:
-
CURLY_BRACE_LEFT
private static final char CURLY_BRACE_LEFT- See Also:
-
CURLY_BRACE_RIGHT
private static final char CURLY_BRACE_RIGHT- See Also:
-
STATE_INITIAL
private static final int STATE_INITIAL- See Also:
-
STATE_SINGLE_QUOTE
private static final int STATE_SINGLE_QUOTE- See Also:
-
STATE_IN_QUOTE
private static final int STATE_IN_QUOTE- See Also:
-
STATE_MSG_ELEMENT
private static final int STATE_MSG_ELEMENT- See Also:
-
-
Constructor Details
-
MessageFormat
Constructs a MessageFormat for the defaultFORMAT
locale and the specified pattern. Sets the locale and calls applyPattern(pattern).- Parameters:
pattern
- the pattern for this message format- Throws:
IllegalArgumentException
- if the pattern is invalid- See Also:
-
MessageFormat
Constructs a MessageFormat for the specified locale and pattern. Sets the locale and calls applyPattern(pattern).- Parameters:
pattern
- the pattern for this message formatlocale
- the locale for this message format- Throws:
IllegalArgumentException
- if the pattern is invalid
-
MessageFormat
Constructs a MessageFormat for the specified locale and pattern. Sets the locale and calls applyPattern(pattern).- Parameters:
pattern
- the pattern for this message formatlocale
- the locale for this message format- Throws:
IllegalArgumentException
- if the pattern is invalid
-
-
Method Details
-
setLocale
Sets the locale to be used for creating argument Format objects. This affects subsequent calls to theapplyPattern
method as well as to theformat
andformatToCharacterIterator
methods.- Parameters:
locale
- the locale to be used when creating or comparing subformats
-
setLocale
Sets the locale to be used for creating argument Format objects. This affects subsequent calls to theapplyPattern
method as well as to theformat
andformatToCharacterIterator
methods.- Parameters:
locale
- the locale to be used when creating or comparing subformats
-
getLocale
Returns the locale that's used when creating or comparing subformats.- Returns:
- the locale used when creating or comparing subformats
-
getULocale
Returns the locale that's used when creating argument Format objects.- Returns:
- the locale used when creating or comparing subformats
-
applyPattern
Sets the pattern used by this message format. Parses the pattern and caches Format objects for simple argument types. Patterns and their interpretation are specified in the class description.- Parameters:
pttrn
- the pattern for this message format- Throws:
IllegalArgumentException
- if the pattern is invalid
-
applyPattern
Sets the ApostropheMode and the pattern used by this message format. Parses the pattern and caches Format objects for simple argument types. Patterns and their interpretation are specified in the class description.This method is best used only once on a given object to avoid confusion about the mode, and after constructing the object with an empty pattern string to minimize overhead.
- Parameters:
pattern
- the pattern for this message formataposMode
- the new ApostropheMode- Throws:
IllegalArgumentException
- if the pattern is invalid- See Also:
-
getApostropheMode
- Returns:
- this instance's ApostropheMode.
-
toPattern
Returns the applied pattern string.- Returns:
- the pattern string
- Throws:
IllegalStateException
- after custom Format objects have been set via setFormat() or similar APIs
-
nextTopLevelArgStart
private int nextTopLevelArgStart(int partIndex) Returns the part index of the next ARG_START after partIndex, or -1 if there is none more.- Parameters:
partIndex
- Part index of the previous ARG_START (initially 0).
-
argNameMatches
-
getArgName
-
setFormatsByArgumentIndex
Sets the Format objects to use for the values passed intoformat
methods or returned fromparse
methods. The indices of elements innewFormats
correspond to the argument indices used in the previously set pattern string. The order of formats innewFormats
thus corresponds to the order of elements in thearguments
array passed to theformat
methods or the result array returned by theparse
methods.If an argument index is used for more than one format element in the pattern string, then the corresponding new format is used for all such format elements. If an argument index is not used for any format element in the pattern string, then the corresponding new format is ignored. If fewer formats are provided than needed, then only the formats for argument indices less than
newFormats.length
are replaced. This method is only supported if the format does not use named arguments, otherwise an IllegalArgumentException is thrown.- Parameters:
newFormats
- the new formats to use- Throws:
NullPointerException
- ifnewFormats
is nullIllegalArgumentException
- if this formatter uses named arguments
-
setFormatsByArgumentName
Sets the Format objects to use for the values passed intoformat
methods or returned fromparse
methods. The keys innewFormats
are the argument names in the previously set pattern string, and the values are the formats.Only argument names from the pattern string are considered. Extra keys in
newFormats
that do not correspond to an argument name are ignored. Similarly, if there is no format in newFormats for an argument name, the formatter for that argument remains unchanged.This may be called on formats that do not use named arguments. In this case the map will be queried for key Strings that represent argument indices, e.g. "0", "1", "2" etc.
- Parameters:
newFormats
- a map from String to Format providing new formats for named arguments.
-
setFormats
Sets the Format objects to use for the format elements in the previously set pattern string. The order of formats innewFormats
corresponds to the order of format elements in the pattern string.If more formats are provided than needed by the pattern string, the remaining ones are ignored. If fewer formats are provided than needed, then only the first
newFormats.length
formats are replaced.Since the order of format elements in a pattern string often changes during localization, it is generally better to use the
setFormatsByArgumentIndex
method, which assumes an order of formats corresponding to the order of elements in thearguments
array passed to theformat
methods or the result array returned by theparse
methods.- Parameters:
newFormats
- the new formats to use- Throws:
NullPointerException
- ifnewFormats
is null
-
setFormatByArgumentIndex
Sets the Format object to use for the format elements within the previously set pattern string that use the given argument index. The argument index is part of the format element definition and represents an index into thearguments
array passed to theformat
methods or the result array returned by theparse
methods.If the argument index is used for more than one format element in the pattern string, then the new format is used for all such format elements. If the argument index is not used for any format element in the pattern string, then the new format is ignored. This method is only supported when exclusively numbers are used for argument names. Otherwise an IllegalArgumentException is thrown.
- Parameters:
argumentIndex
- the argument index for which to use the new formatnewFormat
- the new format to use- Throws:
IllegalArgumentException
- if this format uses named arguments
-
setFormatByArgumentName
Sets the Format object to use for the format elements within the previously set pattern string that use the given argument name.If the argument name is used for more than one format element in the pattern string, then the new format is used for all such format elements. If the argument name is not used for any format element in the pattern string, then the new format is ignored.
This API may be used on formats that do not use named arguments. In this case
argumentName
should be a String that names an argument index, e.g. "0", "1", "2"... etc. If it does not name a valid index, the format will be ignored. No error is thrown.- Parameters:
argumentName
- the name of the argument to changenewFormat
- the new format to use
-
setFormat
Sets the Format object to use for the format element with the given format element index within the previously set pattern string. The format element index is the zero-based number of the format element counting from the start of the pattern string.Since the order of format elements in a pattern string often changes during localization, it is generally better to use the
setFormatByArgumentIndex
method, which accesses format elements based on the argument index they specify.- Parameters:
formatElementIndex
- the index of a format element within the patternnewFormat
- the format to use for the specified format element- Throws:
ArrayIndexOutOfBoundsException
- if formatElementIndex is equal to or larger than the number of format elements in the pattern string
-
getFormatsByArgumentIndex
Returns the Format objects used for the values passed intoformat
methods or returned fromparse
methods. The indices of elements in the returned array correspond to the argument indices used in the previously set pattern string. The order of formats in the returned array thus corresponds to the order of elements in thearguments
array passed to theformat
methods or the result array returned by theparse
methods.If an argument index is used for more than one format element in the pattern string, then the format used for the last such format element is returned in the array. If an argument index is not used for any format element in the pattern string, then null is returned in the array. This method is only supported when exclusively numbers are used for argument names. Otherwise an IllegalArgumentException is thrown.
- Returns:
- the formats used for the arguments within the pattern
- Throws:
IllegalArgumentException
- if this format uses named arguments
-
getFormats
Returns the Format objects used for the format elements in the previously set pattern string. The order of formats in the returned array corresponds to the order of format elements in the pattern string.Since the order of format elements in a pattern string often changes during localization, it's generally better to use the
getFormatsByArgumentIndex()
method, which assumes an order of formats corresponding to the order of elements in thearguments
array passed to theformat
methods or the result array returned by theparse
methods. This method is only supported when exclusively numbers are used for argument names. Otherwise an IllegalArgumentException is thrown.- Returns:
- the formats used for the format elements in the pattern
- Throws:
IllegalArgumentException
- if this format uses named arguments
-
getArgumentNames
Returns the top-level argument names. For more details, seesetFormatByArgumentName(String, Format)
.- Returns:
- a Set of argument names
-
getFormatByArgumentName
Returns the first top-level format associated with the given argument name. For more details, seesetFormatByArgumentName(String, Format)
.- Parameters:
argumentName
- The name of the desired argument.- Returns:
- the Format associated with the name, or null if there isn't one.
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format
Formats an array of objects and appends theMessageFormat
's pattern, with arguments replaced by the formatted objects, to the providedStringBuffer
.The text substituted for the individual format elements is derived from the current subformat of the format element and the
arguments
element at the format element's argument index as indicated by the first matching line of the following table. An argument is unavailable ifarguments
isnull
or has fewer than argumentIndex+1 elements. When an argument is unavailable no substitution is performed.argType or Format value object Formatted Text any unavailable "{" + argNameOrNumber + "}"
any null
"null"
custom Format != null
any customFormat.format(argument)
noneArg, or custom Format == null
instanceof Number
NumberFormat.getInstance(getLocale()).format(argument)
noneArg, or custom Format == null
instanceof Date
DateFormat.getDateTimeInstance(DateFormat.SHORT, DateFormat.SHORT, getLocale()).format(argument)
noneArg, or custom Format == null
instanceof String
argument
noneArg, or custom Format == null
any argument.toString()
complexArg any result of recursive formatting of a selected sub-message If
pos
is non-null, and refers toField.ARGUMENT
, the location of the first formatted string will be returned. This method is only supported when the format does not use named arguments, otherwise an IllegalArgumentException is thrown.- Parameters:
arguments
- an array of objects to be formatted and substituted.result
- where text is appended.pos
- On input: an alignment field, if desired. On output: the offsets of the alignment field.- Throws:
IllegalArgumentException
- if a value in thearguments
array is not of the type expected by the corresponding argument or custom Format object.IllegalArgumentException
- if this format uses named arguments
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format
public final StringBuffer format(Map<String, Object> arguments, StringBuffer result, FieldPosition pos) Formats a map of objects and appends theMessageFormat
's pattern, with arguments replaced by the formatted objects, to the providedStringBuffer
.The text substituted for the individual format elements is derived from the current subformat of the format element and the
arguments
value corresponding to the format element's argument name.A numbered pattern argument is matched with a map key that contains that number as an ASCII-decimal-digit string (without leading zero).
An argument is unavailable if
arguments
isnull
or does not have a value corresponding to an argument name in the pattern. When an argument is unavailable no substitution is performed.- Parameters:
arguments
- a map of objects to be formatted and substituted.result
- where text is appended.pos
- On input: an alignment field, if desired. On output: the offsets of the alignment field.- Returns:
- the passed-in StringBuffer
- Throws:
IllegalArgumentException
- if a value in thearguments
array is not of the type expected by the corresponding argument or custom Format object.
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format
Creates a MessageFormat with the given pattern and uses it to format the given arguments. This is equivalent to(new
MessageFormat
(pattern)).format
(arguments, new StringBuffer(), null).toString()- Throws:
IllegalArgumentException
- if the pattern is invalidIllegalArgumentException
- if a value in thearguments
array is not of the type expected by the corresponding argument or custom Format object.IllegalArgumentException
- if this format uses named arguments
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format
Creates a MessageFormat with the given pattern and uses it to format the given arguments. The pattern must identifyarguments by name instead of by number.- Throws:
IllegalArgumentException
- if the pattern is invalidIllegalArgumentException
- if a value in thearguments
array is not of the type expected by the corresponding argument or custom Format object.- See Also:
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usesNamedArguments
public boolean usesNamedArguments()Returns true if this MessageFormat uses named arguments, and false otherwise. See class description.- Returns:
- true if named arguments are used.
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format
Formats a map or array of objects and appends theMessageFormat
's pattern, with format elements replaced by the formatted objects, to the providedStringBuffer
. This is equivalent to either offormat
((Object[]) arguments, result, pos)format
((Map) arguments, result, pos)- Specified by:
format
in classFormat
- Parameters:
arguments
- a map or array of objects to be formattedresult
- where text is appendedpos
- On input: an alignment field, if desired On output: the offsets of the alignment field- Throws:
IllegalArgumentException
- if an argument inarguments
is not of the type expected by the format element(s) that use itIllegalArgumentException
- ifarguments
is an array of Object and this format uses named arguments
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formatToCharacterIterator
Formats an array of objects and inserts them into theMessageFormat
's pattern, producing anAttributedCharacterIterator
. You can use the returnedAttributedCharacterIterator
to build the resulting String, as well as to determine information about the resulting String.The text of the returned
AttributedCharacterIterator
is the same that would be returned byformat
(arguments, new StringBuffer(), null).toString()In addition, the
AttributedCharacterIterator
contains at least attributes indicating where text was generated from an argument in thearguments
array. The keys of these attributes are of typeMessageFormat.Field
, their values areInteger
objects indicating the index in thearguments
array of the argument from which the text was generated.The attributes/value from the underlying
Format
instances thatMessageFormat
uses will also be placed in the resultingAttributedCharacterIterator
. This allows you to not only find where an argument is placed in the resulting String, but also which fields it contains in turn.- Overrides:
formatToCharacterIterator
in classFormat
- Parameters:
arguments
- an array of objects to be formatted and substituted.- Returns:
- AttributedCharacterIterator describing the formatted value.
- Throws:
NullPointerException
- ifarguments
is null.IllegalArgumentException
- if a value in thearguments
array is not of the type expected by the corresponding argument or custom Format object.
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parse
Parses the string.Caveats: The parse may fail in a number of circumstances. For example:
- If one of the arguments does not occur in the pattern.
- If the format of an argument loses information, such as with a choice format where a large number formats to "many".
- Does not yet handle recursion (where the substituted strings contain {n} references.)
- Will not always find a match (or the correct match) if some part of the parse is ambiguous. For example, if the pattern "{1},{2}" is used with the string arguments {"a,b", "c"}, it will format as "a,b,c". When the result is parsed, it will return {"a", "b,c"}.
- If a single argument is parsed more than once in the string, then the later parse wins.
- Throws:
IllegalArgumentException
- if this format uses named arguments
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parseToMap
Parses the string, returning the results in a Map. This is similar to the version that returns an array of Object. This supports both named and numbered arguments-- if numbered, the keys in the map are the corresponding ASCII-decimal-digit strings (e.g. "0", "1", "2"...).- Parameters:
source
- the text to parsepos
- the position at which to start parsing. on return, contains the result of the parse.- Returns:
- a Map containing key/value pairs for each parsed argument.
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parse
Parses text from the beginning of the given string to produce an object array. The method may not use the entire text of the given string.See the
parse(String, ParsePosition)
method for more information on message parsing.- Parameters:
source
- AString
whose beginning should be parsed.- Returns:
- An
Object
array parsed from the string. - Throws:
ParseException
- if the beginning of the specified string cannot be parsed.IllegalArgumentException
- if this format uses named arguments
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parse
private void parse(int msgStart, String source, ParsePosition pos, Object[] args, Map<String, Object> argsMap) Parses the string, filling either the Map or the Array. This is a private method that all the public parsing methods call. This supports both named and numbered arguments-- if numbered, the keys in the map are the corresponding ASCII-decimal-digit strings (e.g. "0", "1", "2"...).- Parameters:
msgStart
- index in the message pattern to start from.source
- the text to parsepos
- the position at which to start parsing. on return, contains the result of the parse.args
- if not null, the parse results will be filled here (The pattern has to have numbered arguments in order for this to not be null).argsMap
- if not null, the parse results will be filled here.
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parseToMap
Parses text from the beginning of the given string to produce a map from argument to values. The method may not use the entire text of the given string.See the
parse(String, ParsePosition)
method for more information on message parsing.- Parameters:
source
- AString
whose beginning should be parsed.- Returns:
- A
Map
parsed from the string. - Throws:
ParseException
- if the beginning of the specified string cannot be parsed.- See Also:
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parseObject
Parses text from a string to produce an object array or Map.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 object array 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 message 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:
- An
Object
parsed from the string, either an array of Object, or a Map, depending on whether named arguments are used. This can be queried usingusesNamedArguments
. In case of error, returns null. - Throws:
NullPointerException
- ifpos
is null.
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clone
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equals
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hashCode
public int hashCode() -
getStockDateFormatter
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getStockNumberFormatter
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format
private void format(int msgStart, MessageFormat.PluralSelectorContext pluralNumber, Object[] args, Map<String, Object> argsMap, MessageFormat.AppendableWrapper dest, FieldPosition fp) Formats the arguments and writes the result into the AppendableWrapper, updates the field position.Exactly one of args and argsMap must be null, the other non-null.
- Parameters:
msgStart
- Index to msgPattern part to start formatting from.pluralNumber
- null except when formatting a plural argument sub-message where a '#' is replaced by the format string for this number.args
- The formattable objects array. Non-null iff numbered values are used.argsMap
- The key-value map of formattable objects. Non-null iff named values are used.dest
- Output parameter to receive the result. The result (string & attributes) is appended to existing contents.fp
- Field position status.
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formatComplexSubMessage
private void formatComplexSubMessage(int msgStart, MessageFormat.PluralSelectorContext pluralNumber, Object[] args, Map<String, Object> argsMap, MessageFormat.AppendableWrapper dest) -
getLiteralStringUntilNextArgument
Read as much literal string from the pattern string as possible. This stops as soon as it finds an argument, or it reaches the end of the string.- Parameters:
from
- Index in the pattern string to start from.- Returns:
- A substring from the pattern string representing the longest possible substring with no arguments.
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updateMetaData
private FieldPosition updateMetaData(MessageFormat.AppendableWrapper dest, int prevLength, FieldPosition fp, Object argId) -
findChoiceSubMessage
Finds the ChoiceFormat sub-message for the given number.- Parameters:
pattern
- A MessagePattern.partIndex
- the index of the first ChoiceFormat argument style part.number
- a number to be mapped to one of the ChoiceFormat argument's intervals- Returns:
- the sub-message start part index.
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parseChoiceArgument
private static double parseChoiceArgument(MessagePattern pattern, int partIndex, String source, ParsePosition pos) -
matchStringUntilLimitPart
private static int matchStringUntilLimitPart(MessagePattern pattern, int partIndex, int limitPartIndex, String source, int sourceOffset) Matches the pattern string from the end of the partIndex to the beginning of the limitPartIndex, including all syntax except SKIP_SYNTAX, against the source string starting at sourceOffset. If they match, returns the length of the source string match. Otherwise returns -1. -
findOtherSubMessage
private int findOtherSubMessage(int partIndex) Finds the "other" sub-message.- Parameters:
partIndex
- the index of the first PluralFormat argument style part.- Returns:
- the "other" sub-message start part index.
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findFirstPluralNumberArg
Returns the ARG_START index of the first occurrence of the plural number in a sub-message. Returns -1 if it is a REPLACE_NUMBER. Returns 0 if there is neither. -
format
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format
private void format(Object[] arguments, Map<String, Object> argsMap, MessageFormat.AppendableWrapper dest, FieldPosition fp) Internal routine used by format.- Throws:
IllegalArgumentException
- if an argument in thearguments
map is not of the type expected by the format element(s) that use it.
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resetPattern
private void resetPattern() -
dateTimeFormatForPatternOrSkeleton
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createAppropriateFormat
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findKeyword
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writeObject
Custom serialization, new in ICU 4.8. We do not want to use default serialization because we only have a small amount of persistent state which is better expressed explicitly rather than via writing field objects.- Parameters:
out
- The output stream.- Throws:
IOException
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readObject
Custom deserialization, new in ICU 4.8. See comments on writeObject().- Throws:
InvalidObjectException
- if the objects read from the stream is invalid.IOException
ClassNotFoundException
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cacheExplicitFormats
private void cacheExplicitFormats() -
setArgStartFormat
Sets a formatter for a MessagePattern ARG_START part index. -
setCustomArgStartFormat
Sets a custom formatter for a MessagePattern ARG_START part index. "Custom" formatters are provided by the user via setFormat() or similar APIs. -
autoQuoteApostrophe
Converts an 'apostrophe-friendly' pattern into a standard pattern. This is obsolete for ICU 4.8 and higher MessageFormat pattern strings. It can still be useful together withMessageFormat
.See the class description for more about apostrophes and quoting, and differences between ICU and
MessageFormat
.MessageFormat
and ICU 4.6 and earlier MessageFormat treat all ASCII apostrophes as quotes, which is problematic in some languages, e.g. French, where apostrophe is commonly used. This utility assumes that only an unpaired apostrophe immediately before a brace is a true quote. Other unpaired apostrophes are paired, and the resulting standard pattern string is returned.Note: It is not guaranteed that the returned pattern is indeed a valid pattern. The only effect is to convert between patterns having different quoting semantics.
Note: This method only works on top-level messageText, not messageText nested inside a complexArg.
- Parameters:
pattern
- the 'apostrophe-friendly' pattern to convert- Returns:
- the standard equivalent of the original pattern
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