com.ibm.icu.text
Class MessageFormat

java.lang.Object
  java.text.Format
      com.ibm.icu.text.UFormat
          com.ibm.icu.text.MessageFormat

All Implemented Interfaces:

Serializable, Cloneable

public class MessageFormat
extends UFormat

[icu enhancement] ICU's replacement for java.text.MessageFormat. Methods, fields, and other functionality specific to ICU are labeled '[icu]'.

MessageFormat produces concatenated messages in a language-neutral way. Use this whenever concatenating strings that are displayed to end users.

A MessageFormat contains an array of subformats arranged within a template string. Together, the subformats and template string determine how the MessageFormat will operate during formatting and parsing.

Typically, both the subformats and the template string are specified at once in a pattern. By using different patterns for different locales, messages may be localized.

When formatting, MessageFormat takes a collection of arguments and produces a user-readable string. The arguments may be passed as an array or as a Map. Each argument is matched up with its corresponding subformat, which then formats it into a string. The resulting strings are then assembled within the string template of the MessageFormat to produce the final output string.

Note: 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). The 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.

Note: In ICU 3.8 MessageFormat supports named arguments. If a named argument is used, all arguments must be named. Names start with a character in :ID_START: and continue with characters in :ID_CONTINUE:, in particular they do not start with a digit. If named arguments are used, usesNamedArguments() will return true.

The other new methods supporting named arguments are setFormatsByArgumentName(Map), setFormatByArgumentName(String, Format), format(Map, StringBuffer, FieldPosition), format(String, Map), parseToMap(String, ParsePosition), and parseToMap(String). These methods are all compatible with patterns that do not used named arguments-- in these cases the keys in the input or output Maps use Strings that name the argument indices, e.g. "0", "1", "2"... etc.

When named arguments are used, certain methods on MessageFormat that take or return arrays will throw an exception, since it is not possible to identify positions in an array using a name. These methods are setFormatsByArgumentIndex(Format[]), setFormatByArgumentIndex(int, Format), getFormatsByArgumentIndex(), getFormats(), format(Object[], StringBuffer, FieldPosition), format(String, Object[]), parse(String, ParsePosition), and parse(String). These APIs all have corresponding new versions as listed above.

The API format(Object, StringBuffer, FieldPosition) has been modified so that the Object argument can be either an Object array or a Map. If this format uses named arguments, this argument must not be an Object array otherwise an exception will be thrown. If the argument is a Map it can be used with Strings that represent indices as described above.

Patterns and Their Interpretation

MessageFormat uses patterns of the following form:

 MessageFormatPattern:
         String
         MessageFormatPattern FormatElement String

 FormatElement:
         { ArgumentIndexOrName }
         { ArgumentIndexOrName , FormatType }
         { ArgumentIndexOrName , FormatType , FormatStyle }

 ArgumentIndexOrName: one of 
         ['0'-'9']+
         [:ID_START:][:ID_CONTINUE:]*

 FormatType: one of 
         number date time choice spellout ordinal duration plural

 FormatStyle:
         short
         medium
         long
         full
         integer
         currency
         percent
         SubformatPattern
         RulesetName

 String:
         StringPartopt
         String StringPart

 StringPart:
         ''
         ' QuotedString '
         UnquotedString

 SubformatPattern:
         SubformatPatternPartopt
         SubformatPattern SubformatPatternPart

 SubFormatPatternPart:
         ' QuotedPattern '
         UnquotedPattern
 

RulesetName: UnquotedString

Within a String, "''" represents a single quote. A QuotedString can contain arbitrary characters except single quotes; the surrounding single quotes are removed. An UnquotedString can contain arbitrary characters except single quotes and left curly brackets. Thus, a string that should result in the formatted message "'{0}'" can be written as "'''{'0}''" or "'''{0}'''".

Within a SubformatPattern, different rules apply. A QuotedPattern can contain arbitrary characters except single quotes; but the surrounding single quotes are not removed, so they may be interpreted by the subformat. For example, "{1,number,$'#',##}" will produce a number format with the pound-sign quoted, with a result such as: "$#31,45". An UnquotedPattern can contain arbitrary characters except single quotes, but curly braces within it must be balanced. For example, "ab {0} de" and "ab '}' de" are valid subformat patterns, but "ab {0'}' de" and "ab } de" are not.

Warning:

The rules for using quotes within message format patterns unfortunately have shown to be somewhat confusing. In particular, it isn't always obvious to localizers whether single quotes need to be doubled or not. Make sure to inform localizers about the rules, and tell them (for example, by using comments in resource bundle source files) which strings will be processed by MessageFormat. Note that localizers may need to use single quotes in translated strings where the original version doesn't have them.
Note also that the simplest way to avoid the problem is to use the real apostrophe (single quote) character ’ (') for human-readable text, and to use the ASCII apostrophe (' ' ) only in program syntax, like quoting in MessageFormat. See the annotations for U+0027 Apostrophe in The Unicode Standard.

The ArgumentIndex value is a non-negative integer written using the digits '0' through '9', and represents an index into the arguments array passed to the format methods or the result array returned by the parse methods.

The FormatType and FormatStyle 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. A SubformatPattern must be a valid pattern string for the Format subclass used.

Format Type	Format Style	Subformat Created
(none)		null
number	(none)	NumberFormat.getInstance(getLocale())
	integer	NumberFormat.getIntegerInstance(getLocale())
	currency	NumberFormat.getCurrencyInstance(getLocale())
	percent	NumberFormat.getPercentInstance(getLocale())
	SubformatPattern	new DecimalFormat(subformatPattern, new DecimalFormatSymbols(getLocale()))
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())
	SubformatPattern	new SimpleDateFormat(subformatPattern, 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())
	SubformatPattern	new SimpleDateFormat(subformatPattern, getLocale())
choice	SubformatPattern	new ChoiceFormat(subformatPattern)
spellout	RulesetName (optional)	new RuleBasedNumberFormat(getLocale(), RuleBasedNumberFormat.SPELLOUT) .setDefaultRuleset(ruleset);
ordinal	RulesetName (optional)	new RuleBasedNumberFormat(getLocale(), RuleBasedNumberFormat.ORDINAL) .setDefaultRuleset(ruleset);
duration	RulesetName (optional)	new RuleBasedNumberFormat(getLocale(), RuleBasedNumberFormat.DURATION) .setDefaultRuleset(ruleset);
plural	SubformatPattern	new PluralFormat(subformatPattern)
select	SubformatPattern	new SelectFormat(subformatPattern)

Usage Information

Here are some examples of usage:

 Object[] arguments = {
     new Integer(7),
     new Date(System.currentTimeMillis()),
     "a disturbance in the Force"
 };

 String result = MessageFormat.format(
     "At {1,time} on {1,date}, there was {2} on planet {0,number,integer}.",
     arguments);

 output: At 12:30 PM on Jul 3, 2053, there was a disturbance
           in the Force on planet 7.

 

Typically, the message format will come from resources, and the arguments will be dynamically set at runtime.

Example 2:

 Object[] testArgs = {new Long(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).
 

Creating internationalized messages that include plural forms, you can use a PluralFormat:

 MessageFormat msgFmt = new MessageFormat("{0, plural, " +
     "one{{0, number, C''''est #,##0.0#  fichier}} " +
     "other {Ce sont # fichiers}} dans la liste.",
     new ULocale("fr"));
 Object args[] = {new Long(0)};
 System.out.println(msgFmt.format(args));
 args = {new Long(3)};
 System.out.println(msgFmt.format(args));
 
 Produces the output:

 C'est 0,0 fichier dans la liste.

 Ce sont 3 fichiers dans la liste."
 

Please check PluralFormat and PluralRules for details.

Synchronization

Message 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.

Author:

Mark Davis

See Also:

Locale, Format, NumberFormat, DecimalFormat, ChoiceFormat, PluralFormat, SelectFormat, Serialized Form

Status:

Stable ICU 3.0.

Nested Class Summary

static class

MessageFormat.Field Defines constants that are used as attribute keys in the AttributedCharacterIterator returned from MessageFormat.formatToCharacterIterator.

Constructor Summary

MessageFormat(String pattern)
Constructs a MessageFormat for the default locale and the specified pattern.

MessageFormat(String pattern, Locale locale)
Constructs a MessageFormat for the specified locale and pattern.

MessageFormat(String pattern, ULocale locale)
Constructs a MessageFormat for the specified locale and pattern.

Method Summary

void	applyPattern(String pttrn) Sets the pattern used by this message format.
static String	autoQuoteApostrophe(String pattern) [icu] Converts an 'apostrophe-friendly' pattern into a standard pattern.
Object	clone() Overrides clone.
boolean	equals(Object obj) Overrides equals.
StringBuffer	format(Map<String,Object> arguments, StringBuffer result, FieldPosition pos) Formats a map of objects and appends the MessageFormat's pattern, with format elements replaced by the formatted objects, to the provided StringBuffer.
StringBuffer	format(Object[] arguments, StringBuffer result, FieldPosition pos) Formats an array of objects and appends the MessageFormat's pattern, with format elements replaced by the formatted objects, to the provided StringBuffer.
StringBuffer	format(Object arguments, StringBuffer result, FieldPosition pos) Formats a map or array of objects and appends the MessageFormat's pattern, with format elements replaced by the formatted objects, to the provided StringBuffer.
static String	format(String pattern, Map<String,Object> arguments) Creates a MessageFormat with the given pattern and uses it to format the given arguments.
static String	format(String pattern, Object... arguments) Creates a MessageFormat with the given pattern and uses it to format the given arguments.
AttributedCharacterIterator	formatToCharacterIterator(Object arguments) Formats an array of objects and inserts them into the MessageFormat's pattern, producing an AttributedCharacterIterator.
Set<String>	getFormatArgumentNames() Deprecated. This API is ICU internal only.
Format	getFormatByArgumentName(String argumentName) Deprecated. This API is ICU internal only.
Format[]	getFormats() Returns the formats used for the format elements in the previously set pattern string.
Format[]	getFormatsByArgumentIndex() Returns the formats used for the values passed into format methods or returned from parse methods.
Locale	getLocale() Returns the locale that's used when creating or comparing subformats.
ULocale	getULocale() [icu] Returns the locale that's used when creating or comparing subformats.
int	hashCode() Overrides hashCode.
Object[]	parse(String source) Parses text from the beginning of the given string to produce an object array.
Object[]	parse(String source, ParsePosition pos) Parses the string.
Object	parseObject(String source, ParsePosition pos) Parses text from a string to produce an object array or Map.
Map<String,Object>	parseToMap(String source) [icu] Parses text from the beginning of the given string to produce a map from argument to values.
Map<String,Object>	parseToMap(String source, ParsePosition pos) [icu] Parses the string, returning the results in a Map.
void	setFormat(int formatElementIndex, Format newFormat) Sets the format 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 to use for the format elements within the previously set pattern string that use the given argument index.
void	setFormatByArgumentName(String argumentName, Format newFormat) [icu] Sets the format to use for the format elements within the previously set pattern string that use the given argument name.
void	setFormats(Format[] newFormats) Sets the formats to use for the format elements in the previously set pattern string.
void	setFormatsByArgumentIndex(Format[] newFormats) Sets the formats to use for the values passed into format methods or returned from parse methods.
void	setFormatsByArgumentName(Map<String,Format> newFormats) [icu] Sets the formats to use for the values passed into format methods or returned from parse methods.
void	setLocale(Locale locale) Sets the locale to be used when creating or comparing subformats.
void	setLocale(ULocale locale) Sets the locale to be used when creating or comparing subformats.
String	toPattern() Returns a pattern representing the current state of the message format.
boolean	usesNamedArguments() [icu] Returns true if this MessageFormat uses named arguments, and false otherwise.

Methods inherited from class com.ibm.icu.text.UFormat

getLocale

Methods inherited from class java.text.Format

format, parseObject

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

MessageFormat

public MessageFormat(String pattern)

Constructs a MessageFormat for the default locale and the specified pattern. The constructor first sets the locale, then parses the pattern and creates a list of subformats for the format elements contained in it. Patterns and their interpretation are specified in the class description.

Parameters:

pattern - the pattern for this message format

Throws:

IllegalArgumentException - if the pattern is invalid

Status:

Stable ICU 3.0.

MessageFormat

public MessageFormat(String pattern,
                     Locale locale)

Constructs a MessageFormat for the specified locale and pattern. The constructor first sets the locale, then parses the pattern and creates a list of subformats for the format elements contained in it. Patterns and their interpretation are specified in the class description.

Parameters:

pattern - the pattern for this message format

locale - the locale for this message format

Throws:

IllegalArgumentException - if the pattern is invalid

Status:

Stable ICU 3.0.

MessageFormat

public MessageFormat(String pattern,
                     ULocale locale)

Constructs a MessageFormat for the specified locale and pattern. The constructor first sets the locale, then parses the pattern and creates a list of subformats for the format elements contained in it. Patterns and their interpretation are specified in the class description.

Parameters:

pattern - the pattern for this message format

locale - the locale for this message format

Throws:

IllegalArgumentException - if the pattern is invalid

Status:

Stable ICU 3.2.

Method Detail

setLocale

public void setLocale(Locale locale)

Sets the locale to be used when creating or comparing subformats. This affects subsequent calls to the applyPattern and toPattern methods as well as to the format and formatToCharacterIterator methods.

Parameters:

locale - the locale to be used when creating or comparing subformats

Status:

Stable ICU 3.0.

setLocale

public void setLocale(ULocale locale)

Sets the locale to be used when creating or comparing subformats. This affects subsequent calls to the applyPattern and toPattern methods as well as to the format and formatToCharacterIterator methods.

Parameters:

locale - the locale to be used when creating or comparing subformats

Status:

Stable ICU 3.2.

getLocale

public Locale getLocale()

Returns the locale that's used when creating or comparing subformats.

Returns:

the locale used when creating or comparing subformats

Status:

Stable ICU 3.0.

getULocale

public ULocale getULocale()

[icu] Returns the locale that's used when creating or comparing subformats.

Returns:

the locale used when creating or comparing subformats

Status:

Stable ICU 3.2.

applyPattern

public void applyPattern(String pttrn)

Sets the pattern used by this message format. The method parses the pattern and creates a list of subformats for the format elements contained in it. Patterns and their interpretation are specified in the class description.

The pattern must contain only named or only numeric arguments, mixing them is not allowed.

Parameters:

pttrn - the pattern for this message format

Throws:

IllegalArgumentException - if the pattern is invalid

Status:

Stable ICU 3.0.

toPattern

public String toPattern()

Returns a pattern representing the current state of the message format. The string is constructed from internal information and therefore does not necessarily equal the previously applied pattern.

Returns:

a pattern representing the current state of the message format

Status:

Stable ICU 3.0.

setFormatsByArgumentIndex

public void setFormatsByArgumentIndex(Format[] newFormats)

Sets the formats to use for the values passed into format methods or returned from parse methods. The indices of elements in newFormats correspond to the argument indices used in the previously set pattern string. The order of formats in newFormats thus corresponds to the order of elements in the arguments array passed to the format methods or the result array returned by the parse 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 - if newFormats is null

IllegalArgumentException - if this formatter uses named arguments

Status:

Stable ICU 3.0.

setFormatsByArgumentName

public void setFormatsByArgumentName(Map<String,Format> newFormats)

[icu] Sets the formats to use for the values passed into format methods or returned from parse methods. The keys in newFormats 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.

Status:

Stable ICU 3.8.

setFormats

public void setFormats(Format[] newFormats)

Sets the formats to use for the format elements in the previously set pattern string. The order of formats in newFormats 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 the arguments array passed to the format methods or the result array returned by the parse methods.

Parameters:

newFormats - the new formats to use

Throws:

NullPointerException - if newFormats is null

Status:

Stable ICU 3.0.

setFormatByArgumentIndex

public void setFormatByArgumentIndex(int argumentIndex,
                                     Format newFormat)

Sets the format 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 the arguments array passed to the format methods or the result array returned by the parse 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 format

newFormat - the new format to use

Throws:

IllegalArgumentException - if this format uses named arguments

Status:

Stable ICU 3.0.

setFormatByArgumentName

public void setFormatByArgumentName(String argumentName,
                                    Format newFormat)

[icu] Sets the format 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 change

newFormat - the new format to use

Status:

Stable ICU 3.8.

setFormat

public void setFormat(int formatElementIndex,
                      Format newFormat)

Sets the format 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 pattern

newFormat - 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

Status:

Stable ICU 3.0.

getFormatsByArgumentIndex

public Format[] getFormatsByArgumentIndex()

Returns the formats used for the values passed into format methods or returned from parse 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 the arguments array passed to the format methods or the result array returned by the parse 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

Status:

Stable ICU 3.0.

getFormats

public Format[] getFormats()

Returns the formats 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 the arguments array passed to the format methods or the result array returned by the parse 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

Status:

Stable ICU 3.0.

getFormatArgumentNames

public Set<String> getFormatArgumentNames()

Deprecated. This API is ICU internal only.

[icu] Returns the format argument names. For more details, see setFormatByArgumentName(String, Format).

Returns:

List of names

Status:

Internal. This API is ICU internal only.

getFormatByArgumentName

public Format getFormatByArgumentName(String argumentName)

Deprecated. This API is ICU internal only.

[icu] Returns the formats according to their argument names. For more details, see setFormatByArgumentName(String, Format).

Returns:

format associated with the name, or null if there isn't one.

Status:

Internal. This API is ICU internal only.

format

public final StringBuffer format(Object[] arguments,
                                 StringBuffer result,
                                 FieldPosition pos)

Formats an array of objects and appends the MessageFormat's pattern, with format elements replaced by the formatted objects, to the provided StringBuffer.

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 if arguments is null or has fewer than argumentIndex+1 elements. When an argument is unavailable no substitution is performed.

Subformat	Argument	Formatted Text
any	unavailable	"{" + argumentIndex + "}"
any	null	"null"
instanceof ChoiceFormat	any	subformat.format(argument).indexOf('{') >= 0 ? (new MessageFormat(subformat.format(argument), getLocale())).format(argument) : subformat.format(argument)
!= null	any	subformat.format(argument)
null	instanceof Number	NumberFormat.getInstance(getLocale()).format(argument)
null	instanceof Date	DateFormat.getDateTimeInstance(DateFormat.SHORT, DateFormat.SHORT, getLocale()).format(argument)
null	instanceof String	argument
null	any	argument.toString()

If pos is non-null, and refers to Field.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 an argument in the arguments array is not of the type expected by the format element(s) that use it.

IllegalArgumentException - if this format uses named arguments

Status:

Stable ICU 3.0.

format

public final StringBuffer format(Map<String,Object> arguments,
                                 StringBuffer result,
                                 FieldPosition pos)

Formats a map of objects and appends the MessageFormat's pattern, with format elements replaced by the formatted objects, to the provided StringBuffer.

The text substituted for the individual format elements is derived from the current subformat of the format element and the arguments value corresopnding to the format element's argument name.

This API may be called on formats that do not use named arguments. In this case the the keys in arguments must be numeric strings (e.g. "0", "1", "2"...).

An argument is unavailable if arguments is null 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 an argument in the arguments array is not of the type expected by the format element(s) that use it.

Status:

Stable ICU 3.8.

format

public static String format(String pattern,
                            Object... arguments)

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 invalid, or if an argument in the arguments array is not of the type expected by the format element(s) that use it.

IllegalArgumentException - if this format uses named arguments

Status:

Stable ICU 3.0.

format

public static String format(String pattern,
                            Map<String,Object> arguments)

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 invalid, or if an argument in the arguments map is not of the type expected by the format element(s) that use it.

See Also:

format(Map, StringBuffer, FieldPosition), format(String, Object[])

Status:

Stable ICU 3.8.

usesNamedArguments

public boolean usesNamedArguments()

[icu] Returns true if this MessageFormat uses named arguments, and false otherwise. See class description.

Returns:

true if named arguments are used.

Status:

Stable ICU 3.8.

format

public final StringBuffer format(Object arguments,
                                 StringBuffer result,
                                 FieldPosition pos)

Formats a map or array of objects and appends the MessageFormat's pattern, with format elements replaced by the formatted objects, to the provided StringBuffer. This is equivalent to either of

format((Object[]) arguments, result, pos) format((Map) arguments, result, pos)

A map must be provided if this format uses named arguments, otherwise an IllegalArgumentException will be thrown.

Specified by:

format in class Format

Parameters:

arguments - a map or array of objects to be formatted

result - where text is appended

pos - On input: an alignment field, if desired On output: the offsets of the alignment field

Throws:

IllegalArgumentException - if an argument in arguments is not of the type expected by the format element(s) that use it

IllegalArgumentException - if arguments is an array of Object and this format uses named arguments

Status:

Stable ICU 3.0.

formatToCharacterIterator

public AttributedCharacterIterator formatToCharacterIterator(Object arguments)

Formats an array of objects and inserts them into the MessageFormat's pattern, producing an AttributedCharacterIterator. You can use the returned AttributedCharacterIterator 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 by

format(arguments, new StringBuffer(), null).toString()

In addition, the AttributedCharacterIterator contains at least attributes indicating where text was generated from an argument in the arguments array. The keys of these attributes are of type MessageFormat.Field, their values are Integer objects indicating the index in the arguments array of the argument from which the text was generated.

The attributes/value from the underlying Format instances that MessageFormat uses will also be placed in the resulting AttributedCharacterIterator. 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 class Format

Parameters:

arguments - an array of objects to be formatted and substituted.

Returns:

AttributedCharacterIterator describing the formatted value.

Throws:

NullPointerException - if arguments is null.

IllegalArgumentException - if an argument in the arguments array is not of the type expected by the format element(s) that use it.

Status:

Stable ICU 3.8.

parse

public Object[] parse(String source,
                      ParsePosition pos)

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.

When the parse fails, use ParsePosition.getErrorIndex() to find out where in the string did the parsing failed. The returned error index is the starting offset of the sub-patterns that the string is comparing with. For example, if the parsing string "AAA {0} BBB" is comparing against the pattern "AAD {0} BBB", the error index is 0. When an error occurs, the call to this method will return null. If the source is null, return an empty array.

This method is only supported with numbered arguments. If the format pattern used named argument an IllegalArgumentException is thrown.

Throws:

IllegalArgumentException - if this format uses named arguments

Status:

Stable ICU 3.0.

parseToMap

public Map<String,Object> parseToMap(String source,
                                     ParsePosition pos)

[icu] 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 Strings (e.g. "0", "1", "2"...).

Parameters:

source - the text to parse

pos - 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.

Status:

Stable ICU 3.8.

parse

public Object[] parse(String source)
               throws ParseException

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 - A String 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

Status:

Stable ICU 3.0.

parseToMap

public Map<String,Object> parseToMap(String source)
                              throws ParseException

[icu] 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 - A String 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:

parseToMap(String, ParsePosition)

Status:

Stable ICU 3.8.

parseObject

public Object parseObject(String source,
                          ParsePosition pos)

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 of pos 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 updated pos can be used to indicate the starting point for the next call to this method. If an error occurs, then the index of pos is not changed, the error index of pos 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 class Format

Parameters:

source - A String, part of which should be parsed.

pos - A ParsePosition 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 using usesNamedArguments. In case of error, returns null.

Throws:

NullPointerException - if pos is null.

Status:

Stable ICU 3.0.

clone

public Object clone()

Overrides clone.

Overrides:

clone in class Format

Returns:

a clone of this instance.

Status:

Stable ICU 3.0.

equals

public boolean equals(Object obj)

Overrides equals.

Overrides:

equals in class Object

Status:

Stable ICU 3.0.

hashCode

public int hashCode()

Overrides hashCode.

Overrides:

hashCode in class Object

Status:

Stable ICU 3.0.

autoQuoteApostrophe

public static String autoQuoteApostrophe(String pattern)

[icu] Converts an 'apostrophe-friendly' pattern into a standard pattern. Standard patterns treat all 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.

Parameters:

pattern - the 'apostrophe-friendly' patttern to convert

Returns:

the standard equivalent of the original pattern

Status:

Stable ICU 3.4.