MessageFormat

 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".
 

MessageFormat

MessageFormat (String pattern)

Constructs a MessageFormat for the default FORMAT locale and the specified pattern. Sets the locale and calls applyPattern(pattern).

Parameters
pattern	String: the pattern for this message format

Throws
IllegalArgumentException	if the pattern is invalid

MessageFormat

MessageFormat (String pattern, 
                Locale locale)

Constructs a MessageFormat for the specified locale and pattern. Sets the locale and calls applyPattern(pattern).

Parameters
pattern	String: the pattern for this message format
locale	Locale: the locale for this message format

Throws
IllegalArgumentException	if the pattern is invalid

MessageFormat

MessageFormat (String pattern, 
                ULocale locale)

Constructs a MessageFormat for the specified locale and pattern. Sets the locale and calls applyPattern(pattern).

Parameters
pattern	String: the pattern for this message format
locale	ULocale: the locale for this message format

Throws
IllegalArgumentException	if the pattern is invalid

applyPattern

void applyPattern (String pttrn)

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	String: the pattern for this message format

Throws
IllegalArgumentException	if the pattern is invalid

applyPattern

void applyPattern (String pattern, 
                MessagePattern.ApostropheMode aposMode)

[icu] 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	String: the pattern for this message format
aposMode	MessagePattern.ApostropheMode: the new ApostropheMode

Throws
IllegalArgumentException	if the pattern is invalid

autoQuoteApostrophe

String autoQuoteApostrophe (String pattern)

[icu] 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 with MessageFormat.

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	String: the 'apostrophe-friendly' pattern to convert

Returns
String	the standard equivalent of the original pattern

clone

Object clone ()

Creates and returns a copy of this object.

Returns
Object	a clone of this instance.

equals

boolean equals (Object obj)

Indicates whether some other object is "equal to" this one.

The equals method implements an equivalence relation on non-null object references:

• It is reflexive: for any non-null reference value x, x.equals(x) should return true.
• It is symmetric: for any non-null reference values x and y, x.equals(y) should return true if and only if y.equals(x) returns true.
• It is transitive: for any non-null reference values x, y, and z, if x.equals(y) returns true and y.equals(z) returns true, then x.equals(z) should return true.
• It is consistent: for any non-null reference values x and y, multiple invocations of x.equals(y) consistently return true or consistently return false, provided no information used in equals comparisons on the objects is modified.
• For any non-null reference value x, x.equals(null) should return false.

The equals method for class Object implements the most discriminating possible equivalence relation on objects; that is, for any non-null reference values x and y, this method returns true if and only if x and y refer to the same object (x == y has the value true).

Note that it is generally necessary to override the hashCode method whenever this method is overridden, so as to maintain the general contract for the hashCode method, which states that equal objects must have equal hash codes.

Parameters
obj	Object: the reference object with which to compare.

Returns
boolean	true if this object is the same as the obj argument; false otherwise.

format

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

Formats an array of objects and appends the MessageFormat's pattern, with arguments 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.

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 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	Object: an array of objects to be formatted and substituted.
result	StringBuffer: where text is appended.
pos	FieldPosition: On input: an alignment field, if desired. On output: the offsets of the alignment field.

Returns
StringBuffer

Throws
IllegalArgumentException	if a value in the arguments array is not of the type expected by the corresponding argument or custom Format object.
IllegalArgumentException	if this format uses named arguments

format

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.

Parameters
pattern	String
arguments	Map

Returns
String

Throws
IllegalArgumentException	if the pattern is invalid
IllegalArgumentException	if a value in the arguments array is not of the type expected by the corresponding argument or custom Format object.

format

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.

Parameters
arguments	Object: a map or array of objects to be formatted
result	StringBuffer: where text is appended
pos	FieldPosition: On input: an alignment field, if desired On output: the offsets of the alignment field

Returns
StringBuffer	the string buffer passed in as toAppendTo, with formatted text appended

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

format

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

Formats a map of objects and appends the MessageFormat's pattern, with arguments 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.

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 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	Map: a map of objects to be formatted and substituted.
result	StringBuffer: where text is appended.
pos	FieldPosition: On input: an alignment field, if desired. On output: the offsets of the alignment field.

Returns
StringBuffer	the passed-in StringBuffer

Throws
IllegalArgumentException	if a value in the arguments array is not of the type expected by the corresponding argument or custom Format object.

format

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()

Parameters
pattern	String
arguments	Object

Returns
String

Throws
IllegalArgumentException	if the pattern is invalid
IllegalArgumentException	if a value in the arguments array is not of the type expected by the corresponding argument or custom Format object.
IllegalArgumentException	if this format uses named arguments

formatToCharacterIterator

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.

Parameters
arguments	Object: an array of objects to be formatted and substituted.

Returns
AttributedCharacterIterator	AttributedCharacterIterator describing the formatted value.

Throws
NullPointerException	if arguments is null.
IllegalArgumentException	if a value in the arguments array is not of the type expected by the corresponding argument or custom Format object.

getApostropheMode

MessagePattern.ApostropheMode getApostropheMode ()

[icu]

Returns
MessagePattern.ApostropheMode	this instance's ApostropheMode.

getArgumentNames

Set<String> getArgumentNames ()

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

Returns
Set<String>	a Set of argument names

getFormatByArgumentName

Format getFormatByArgumentName (String argumentName)

[icu] Returns the first top-level format associated with the given argument name. For more details, see setFormatByArgumentName(String, Format).

Parameters
argumentName	String: The name of the desired argument.

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

getFormats

Format[] 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 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
Format[]	the formats used for the format elements in the pattern

Throws
IllegalArgumentException	if this format uses named arguments

getFormatsByArgumentIndex

Format[] getFormatsByArgumentIndex ()

Returns the Format objects 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
Format[]	the formats used for the arguments within the pattern

Throws
IllegalArgumentException	if this format uses named arguments

getLocale

Locale getLocale ()

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

Returns
Locale	the locale used when creating or comparing subformats

getULocale

ULocale getULocale ()

[icu] Returns the locale that's used when creating argument Format objects.

Returns
ULocale	the locale used when creating or comparing subformats

hashCode

int hashCode ()

Returns a hash code value for the object. This method is supported for the benefit of hash tables such as those provided by HashMap.

The general contract of hashCode is:

• Whenever it is invoked on the same object more than once during an execution of a Java application, the hashCode method must consistently return the same integer, provided no information used in equals comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application.
• If two objects are equal according to the equals(Object) method, then calling the hashCode method on each of the two objects must produce the same integer result.
• It is not required that if two objects are unequal according to the equals(java.lang.Object) method, then calling the hashCode method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hash tables.

As much as is reasonably practical, the hashCode method defined by class Object does return distinct integers for distinct objects. (This is typically implemented by converting the internal address of the object into an integer, but this implementation technique is not required by the Java^TM programming language.)

Returns
int	a hash code value for this object.

parse

Object[] parse (String source)

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	String: A String whose beginning should be parsed.

Returns
Object[]	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

parse

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.

Parameters
source	String
pos	ParsePosition

Returns
Object[]

Throws
IllegalArgumentException	if this format uses named arguments

parseObject

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.

Parameters
source	String: A String, part of which should be parsed.
pos	ParsePosition: A ParsePosition object with index and error index information as described above.

Returns
Object	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.

parseToMap

Map<String, Object> parseToMap (String source)

[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	String: A String whose beginning should be parsed.

Returns
Map<String, Object>	A Map parsed from the string.

Throws
ParseException	if the beginning of the specified string cannot be parsed.

parseToMap

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 ASCII-decimal-digit strings (e.g. "0", "1", "2"...).

Parameters
source	String: the text to parse
pos	ParsePosition: the position at which to start parsing. on return, contains the result of the parse.

Returns
Map<String, Object>	a Map containing key/value pairs for each parsed argument.

setFormat

void setFormat (int formatElementIndex, 
                Format newFormat)

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	int: the index of a format element within the pattern
newFormat	Format: 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

setFormatByArgumentIndex

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. 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	int: the argument index for which to use the new format
newFormat	Format: the new format to use

Throws
IllegalArgumentException	if this format uses named arguments

setFormatByArgumentName

void setFormatByArgumentName (String argumentName, 
                Format newFormat)

[icu] 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	String: the name of the argument to change
newFormat	Format: the new format to use

setFormats

void setFormats (Format[] newFormats)

Sets the Format objects 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	Format: the new formats to use

Throws
NullPointerException	if newFormats is null

setFormatsByArgumentIndex

void setFormatsByArgumentIndex (Format[] newFormats)

Sets the Format objects 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	Format: the new formats to use

Throws
NullPointerException	if newFormats is null
IllegalArgumentException	if this formatter uses named arguments

setFormatsByArgumentName

void setFormatsByArgumentName (Map<String, Format> newFormats)

[icu] Sets the Format objects 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	Map: a map from String to Format providing new formats for named arguments.

setLocale

void setLocale (ULocale locale)

Sets the locale to be used for creating argument Format objects. This affects subsequent calls to the applyPattern method as well as to the format and formatToCharacterIterator methods.

Parameters
locale	ULocale: the locale to be used when creating or comparing subformats

setLocale

void setLocale (Locale locale)

Sets the locale to be used for creating argument Format objects. This affects subsequent calls to the applyPattern method as well as to the format and formatToCharacterIterator methods.

Parameters
locale	Locale: the locale to be used when creating or comparing subformats

toPattern

String toPattern ()

Returns the applied pattern string.

Returns
String	the pattern string

Throws
IllegalStateException	after custom Format objects have been set via setFormat() or similar APIs

usesNamedArguments

boolean usesNamedArguments ()

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

Returns
boolean	true if named arguments are used.