* {@code MessageFormat} takes a set of objects, formats them, then * inserts the formatted strings into the pattern at the appropriate places. * *
* Note: * {@code MessageFormat} differs from the other {@code Format} * classes in that you create a {@code MessageFormat} object with one * of its constructors (not with a {@code getInstance} style factory * method). The factory methods aren't necessary because {@code MessageFormat} * itself doesn't implement locale specific behavior. Any locale specific * behavior is defined by the pattern that you provide as well as the * subformats used for inserted arguments. * *
* MessageFormatPattern:
* String
* MessageFormatPattern FormatElement String
*
* FormatElement:
* { ArgumentIndex }
* { ArgumentIndex , FormatType }
* { ArgumentIndex , FormatType , FormatStyle }
*
* FormatType: one of
* number date time choice
*
* FormatStyle:
* short
* medium
* long
* full
* integer
* currency
* percent
* SubformatPattern
* Within a String, a pair of single quotes can be used to
* quote any arbitrary characters except single quotes. For example,
* pattern string "'{0}'" represents string
* "{0}", not a FormatElement. A single quote itself
* must be represented by doubled single quotes {@code ''} throughout a
* String. For example, pattern string "'{''}'" is
* interpreted as a sequence of '{ (start of quoting and a
* left curly brace), {@code ''} (a single quote), and
* }' (a right curly brace and end of quoting),
* not '{' and '}' (quoted left and
* right curly braces): representing string "{'}",
* not "{}".
*
*
A SubformatPattern is interpreted by its corresponding
* subformat, and subformat-dependent pattern rules apply. For example,
* pattern string "{1,number,$'#',##}"
* (SubformatPattern with underline) will produce a number format
* with the pound-sign quoted, with a result such as: {@code
* "$#31,45"}. Refer to each {@code Format} subclass documentation for
* details.
*
*
Any unmatched quote is treated as closed at the end of the given * pattern. For example, pattern string {@code "'{0}"} is treated as * pattern {@code "'{0}'"}. * *
Any curly braces within an unquoted pattern must be balanced. For
* example, "ab {0} de" and "ab '}' de" are
* valid patterns, but "ab {0'}' de", "ab } de"
* and "''{''" are not.
*
*
* The ArgumentIndex value is a non-negative integer written * using the digits {@code '0'} through {@code '9'}, and represents an index into the * {@code arguments} array passed to the {@code format} methods * or the result array returned by the {@code parse} methods. *
* The FormatType and FormatStyle values are used to create * a {@code Format} instance for the format element. The following * table shows how the values map to {@code Format} instances. Combinations not * shown in the table are illegal. A SubformatPattern must * be a valid pattern string for the {@code Format} subclass used. * *
| FormatType * | FormatStyle * | Subformat Created * |
|---|---|---|
| (none) * | (none) * | {@code null} * |
| {@code number} * | (none) * | {@link NumberFormat#getInstance(Locale) NumberFormat.getInstance}{@code (getLocale())} * |
| {@code integer} * | {@link NumberFormat#getIntegerInstance(Locale) NumberFormat.getIntegerInstance}{@code (getLocale())} * | |
| {@code currency} * | {@link NumberFormat#getCurrencyInstance(Locale) NumberFormat.getCurrencyInstance}{@code (getLocale())} * | |
| {@code percent} * | {@link NumberFormat#getPercentInstance(Locale) NumberFormat.getPercentInstance}{@code (getLocale())} * | |
| SubformatPattern * | {@code new} {@link DecimalFormat#DecimalFormat(String,DecimalFormatSymbols) DecimalFormat}{@code (subformatPattern,} {@link DecimalFormatSymbols#getInstance(Locale) DecimalFormatSymbols.getInstance}{@code (getLocale()))} * | |
| {@code date} * | (none) * | {@link DateFormat#getDateInstance(int,Locale) DateFormat.getDateInstance}{@code (}{@link DateFormat#DEFAULT}{@code , getLocale())} * |
| {@code short} * | {@link DateFormat#getDateInstance(int,Locale) DateFormat.getDateInstance}{@code (}{@link DateFormat#SHORT}{@code , getLocale())} * | |
| {@code medium} * | {@link DateFormat#getDateInstance(int,Locale) DateFormat.getDateInstance}{@code (}{@link DateFormat#DEFAULT}{@code , getLocale())} * | |
| {@code long} * | {@link DateFormat#getDateInstance(int,Locale) DateFormat.getDateInstance}{@code (}{@link DateFormat#LONG}{@code , getLocale())} * | |
| {@code full} * | {@link DateFormat#getDateInstance(int,Locale) DateFormat.getDateInstance}{@code (}{@link DateFormat#FULL}{@code , getLocale())} * | |
| SubformatPattern * | {@code new} {@link SimpleDateFormat#SimpleDateFormat(String,Locale) SimpleDateFormat}{@code (subformatPattern, getLocale())} * | |
| {@code time} * | (none) * | {@link DateFormat#getTimeInstance(int,Locale) DateFormat.getTimeInstance}{@code (}{@link DateFormat#DEFAULT}{@code , getLocale())} * |
| {@code short} * | {@link DateFormat#getTimeInstance(int,Locale) DateFormat.getTimeInstance}{@code (}{@link DateFormat#SHORT}{@code , getLocale())} * | |
| {@code medium} * | {@link DateFormat#getTimeInstance(int,Locale) DateFormat.getTimeInstance}{@code (}{@link DateFormat#DEFAULT}{@code , getLocale())} * | |
| {@code long} * | {@link DateFormat#getTimeInstance(int,Locale) DateFormat.getTimeInstance}{@code (}{@link DateFormat#LONG}{@code , getLocale())} * | |
| {@code full} * | {@link DateFormat#getTimeInstance(int,Locale) DateFormat.getTimeInstance}{@code (}{@link DateFormat#FULL}{@code , getLocale())} * | |
| SubformatPattern * | {@code new} {@link SimpleDateFormat#SimpleDateFormat(String,Locale) SimpleDateFormat}{@code (subformatPattern, getLocale())} * | |
| {@code choice} * | SubformatPattern * | {@code new} {@link ChoiceFormat#ChoiceFormat(String) ChoiceFormat}{@code (subformatPattern)} * |
* Here are some examples of usage. * In real internationalized programs, the message format pattern and other * static strings will, of course, be obtained from resource bundles. * Other parameters will be dynamically determined at runtime. *
* The first example uses the static method {@code MessageFormat.format}, * which internally creates a {@code MessageFormat} for one-time use: * {@snippet lang=java : * int planet = 7; * String event = "a disturbance in the Force"; * * String result = MessageFormat.format( * "At {1,time} on {1,date}, there was {2} on planet {0,number,integer}.", * planet, new Date(), event); * } * The output is: *
* ** At 12:30 PM on Jul 3, 2053, there was a disturbance in the Force on planet 7. *
* The following example creates a {@code MessageFormat} instance that * can be used repeatedly: * {@snippet lang=java : * int fileCount = 1273; * String diskName = "MyDisk"; * Object[] testArgs = {Long.valueOf(fileCount), diskName}; * * MessageFormat form = new MessageFormat( * "The disk \"{1}\" contains {0} file(s)."); * * System.out.println(form.format(testArgs)); * } * The output with different values for {@code fileCount}: *
* ** The disk "MyDisk" contains 0 file(s). * The disk "MyDisk" contains 1 file(s). * The disk "MyDisk" contains 1,273 file(s). *
* For more sophisticated patterns, {@link ChoiceFormat} can be used with * {@code MessageFormat} to produce accurate forms for singular and plural: * {@snippet lang=java : * MessageFormat msgFmt = new MessageFormat("The disk \"{0}\" contains {1}."); * double[] fileLimits = {0,1,2}; * String[] filePart = {"no files","one file","{1,number} files"}; * ChoiceFormat fileChoices = new ChoiceFormat(fileLimits, filePart); * msgFmt.setFormatByArgumentIndex(1, fileChoices); * Object[] args = {"MyDisk", 1273}; * System.out.println(msgFmt.format(args)); * } * The output with different values for {@code fileCount}: *
* ** The disk "MyDisk" contains no files. * The disk "MyDisk" contains one file. * The disk "MyDisk" contains 1,273 files. *
* You can create the {@code ChoiceFormat} programmatically, as in the
* above example, or by using a pattern. See {@link ChoiceFormat}
* for more information.
* {@snippet lang=java :
* msgFmt.applyPattern(
* "There {0,choice,0#are no files|1#is one file|1
* When a single argument is parsed more than once in the string, the last match
* will be the final result of the parsing. For example,
* {@snippet lang=java :
* MessageFormat mf = new MessageFormat("{0,number,#.##}, {0,number,#.#}");
* Object[] objs = {Double.valueOf(3.1415)};
* String result = mf.format( objs );
* // result now equals "3.14, 3.1"
* objs = mf.parse(result, new ParsePosition(0));
* // objs now equals {Double.valueOf(3.1)}
* }
*
*
* Likewise, parsing with a {@code MessageFormat} object using patterns containing
* multiple occurrences of the same argument would return the last match. For
* example,
* {@snippet lang=java :
* MessageFormat mf = new MessageFormat("{0}, {0}, {0}");
* String forParsing = "x, y, z";
* Object[] objs = mf.parse(forParsing, new ParsePosition(0));
* // objs now equals {new String("z")}
* }
*
*
* 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.
*
* @see java.util.Locale
* @see Format
* @see NumberFormat
* @see DecimalFormat
* @see DecimalFormatSymbols
* @see ChoiceFormat
* @see DateFormat
* @see SimpleDateFormat
*
* @author Mark Davis
* @since 1.1
*/
public class MessageFormat extends Format {
@java.io.Serial
private static final long serialVersionUID = 6479157306784022952L;
/**
* Constructs a MessageFormat for the default
* {@link java.util.Locale.Category#FORMAT FORMAT} 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
* {@linkplain ##patterns class description}.
*
* @param pattern the pattern for this message format
* @throws IllegalArgumentException if the pattern is invalid
* @throws NullPointerException if {@code pattern} is
* {@code null}
*/
public MessageFormat(String pattern) {
this.locale = Locale.getDefault(Locale.Category.FORMAT);
applyPatternImpl(pattern);
}
/**
* 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
* {@linkplain ##patterns class description}.
*
* @implSpec The default implementation throws a
* {@code NullPointerException} if {@code locale} is {@code null}
* either during the creation of the {@code MessageFormat} object or later
* when {@code format()} is called by a {@code MessageFormat}
* instance with a null locale and the implementation utilizes a
* locale-dependent subformat.
*
* @param pattern the pattern for this message format
* @param locale the locale for this message format
* @throws IllegalArgumentException if the pattern is invalid
* @throws NullPointerException if {@code pattern} is
* {@code null} or {@code locale} is {@code null} and the
* implementation uses a locale-dependent subformat.
* @since 1.4
*/
public MessageFormat(String pattern, Locale locale) {
this.locale = locale;
applyPatternImpl(pattern);
}
/**
* Sets the locale to be used when creating or comparing subformats.
* This affects subsequent calls
*
* 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 {@code newFormats.length} are replaced.
*
* @param newFormats the new formats to use
* @throws NullPointerException if {@code newFormats} is null
* @since 1.4
*/
public void setFormatsByArgumentIndex(Format[] newFormats) {
for (int i = 0; i <= maxOffset; i++) {
int j = argumentNumbers[i];
if (j < newFormats.length) {
formats[i] = newFormats[j];
}
}
}
/**
* Sets the formats to use for the format elements in the
* previously set pattern string.
* The order of formats in {@code 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 {@code 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
* {@link #setFormatsByArgumentIndex setFormatsByArgumentIndex}
* method, which assumes an order of formats corresponding to the
* order of elements in the {@code arguments} array passed to
* the {@code format} methods or the result array returned by
* the {@code parse} methods.
*
* @param newFormats the new formats to use
* @throws NullPointerException if {@code newFormats} is null
*/
public void setFormats(Format[] newFormats) {
int runsToCopy = newFormats.length;
if (runsToCopy > maxOffset + 1) {
runsToCopy = maxOffset + 1;
}
for (int i = 0; i < runsToCopy; i++) {
formats[i] = newFormats[i];
}
}
/**
* 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 {@code arguments} array passed
* to the {@code format} methods or the result array returned
* by the {@code 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.
*
* @param argumentIndex the argument index for which to use the new format
* @param newFormat the new format to use
* @since 1.4
*/
public void setFormatByArgumentIndex(int argumentIndex, Format newFormat) {
for (int j = 0; j <= maxOffset; j++) {
if (argumentNumbers[j] == argumentIndex) {
formats[j] = 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
* {@link #setFormatByArgumentIndex setFormatByArgumentIndex}
* method, which accesses format elements based on the argument
* index they specify.
*
* @param formatElementIndex the index of a format element within the pattern
* @param newFormat the format to use for the specified format element
* @throws ArrayIndexOutOfBoundsException if {@code formatElementIndex} is equal to or
* larger than the number of format elements in the pattern string
*/
public void setFormat(int formatElementIndex, Format newFormat) {
if (formatElementIndex > maxOffset) {
throw new ArrayIndexOutOfBoundsException(formatElementIndex);
}
formats[formatElementIndex] = newFormat;
}
/**
* Gets the formats used for the values passed into
* {@code format} methods or returned from {@code 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 {@code arguments} array passed
* to the {@code format} methods or the result array returned
* by the {@code 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.
*
* @return the formats used for the arguments within the pattern
* @since 1.4
*/
public Format[] getFormatsByArgumentIndex() {
int maximumArgumentNumber = -1;
for (int i = 0; i <= maxOffset; i++) {
if (argumentNumbers[i] > maximumArgumentNumber) {
maximumArgumentNumber = argumentNumbers[i];
}
}
Format[] resultArray = new Format[maximumArgumentNumber + 1];
for (int i = 0; i <= maxOffset; i++) {
resultArray[argumentNumbers[i]] = formats[i];
}
return resultArray;
}
/**
* Gets 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
* {@link #getFormatsByArgumentIndex getFormatsByArgumentIndex}
* method, which assumes an order of formats corresponding to the
* order of elements in the {@code arguments} array passed to
* the {@code format} methods or the result array returned by
* the {@code parse} methods.
*
* @return the formats used for the format elements in the pattern
*/
public Format[] getFormats() {
Format[] resultArray = new Format[maxOffset + 1];
System.arraycopy(formats, 0, resultArray, 0, maxOffset + 1);
return resultArray;
}
/**
* Formats an array of objects and appends the {@code MessageFormat}'s
* pattern, with format elements replaced by the formatted objects, to the
* provided {@code StringBuffer}.
*
* The text substituted for the individual format elements is derived from
* the current subformat of the format element and the
* {@code 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 {@code arguments} is
* {@code null} or has fewer than argumentIndex+1 elements.
*
*
* If {@code pos} is non-null, and refers to
* {@code Field.ARGUMENT}, the location of the first formatted
* string will be returned.
*
* @param arguments an array of objects to be formatted and substituted.
* @param result where text is appended.
* @param pos keeps track on the position of the first replaced argument
* in the output string.
* @return the string buffer passed in as {@code result}, with formatted
* text appended
* @throws IllegalArgumentException if an argument in the
* {@code arguments} array is not of the type
* expected by the format element(s) that use it.
* @throws NullPointerException if {@code result} is {@code null} or
* if the {@code MessageFormat} instance that calls this method
* has locale set to null, and the implementation
* uses a locale-dependent subformat.
*/
public final StringBuffer format(Object[] arguments, StringBuffer result,
FieldPosition pos)
{
return subformat(arguments, result, pos, null);
}
/**
* Creates a MessageFormat with the given pattern and uses it
* to format the given arguments. This is equivalent to
*
* The text of the returned {@code AttributedCharacterIterator} is
* the same that would be returned by
*
* In addition, the {@code AttributedCharacterIterator} contains at
* least attributes indicating where text was generated from an
* argument in the {@code arguments} array. The keys of these attributes are of
* type {@code MessageFormat.Field}, their values are
* {@code Integer} objects indicating the index in the {@code arguments}
* array of the argument from which the text was generated.
*
* The attributes/value from the underlying {@code Format}
* instances that {@code MessageFormat} uses will also be
* placed in the resulting {@code 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.
*
* @param arguments an array of objects to be formatted and substituted.
* @return AttributedCharacterIterator describing the formatted value.
* @throws NullPointerException if {@code arguments} is null.
* @throws IllegalArgumentException if an argument in the
* {@code arguments} array is not of the type
* expected by the format element(s) that use it.
* @since 1.4
*/
public AttributedCharacterIterator formatToCharacterIterator(Object arguments) {
Objects.requireNonNull(arguments, "arguments must not be null");
StringBuffer result = new StringBuffer();
ArrayList Caveats: The parse may fail in a number of circumstances.
* For example:
*
* See the {@link #parse(String, ParsePosition)} method for more information
* on message parsing.
*
* @param source A {@code String} whose beginning should be parsed.
* @return An {@code Object} array parsed from the string.
* @throws ParseException if the beginning of the specified string
* cannot be parsed.
*/
public Object[] parse(String source) throws ParseException {
ParsePosition pos = new ParsePosition(0);
Object[] result = parse(source, pos);
if (pos.index == 0) // unchanged, returned object is null
throw new ParseException("MessageFormat parse error!", pos.errorIndex);
return result;
}
/**
* Parses text from a string to produce an object array.
*
* The method attempts to parse text starting at the index given by
* {@code pos}.
* If parsing succeeds, then the index of {@code 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 {@code pos} can be used to
* indicate the starting point for the next call to this method.
* If an error occurs, then the index of {@code pos} is not
* changed, the error index of {@code pos} is set to the index of
* the character where the error occurred, and null is returned.
*
* See the {@link #parse(String, ParsePosition)} method for more information
* on message parsing.
*
* @param source A {@code String}, part of which should be parsed.
* @param pos A {@code ParsePosition} object with index and error
* index information as described above.
* @return An {@code Object} array parsed from the string. In case of
* error, returns null.
* @throws NullPointerException if {@code pos} is null.
*/
public Object parseObject(String source, ParsePosition pos) {
return parse(source, pos);
}
/**
* Creates and returns a copy of this object.
*
* @return a clone of this instance.
*/
public Object clone() {
MessageFormat other = (MessageFormat) super.clone();
// clone arrays. Can't do with utility because of bug in Cloneable
other.formats = formats.clone(); // shallow clone
for (int i = 0; i < formats.length; ++i) {
if (formats[i] != null)
other.formats[i] = (Format)formats[i].clone();
}
// for primitives or immutables, shallow clone is enough
other.offsets = offsets.clone();
other.argumentNumbers = argumentNumbers.clone();
return other;
}
/**
* Compares the specified object with this {@code MessageFormat} for equality.
* Returns true if the object is also a {@code MessageFormat} and the
* two formats would format any value the same.
*
* @implSpec This method performs an equality check with a notion of class
* identity based on {@code getClass()}, rather than {@code instanceof}.
* Therefore, in the equals methods in subclasses, no instance of this class
* should compare as equal to an instance of a subclass.
* @param obj object to be compared for equality
* @return {@code true} if the specified object is equal to this {@code MessageFormat}
* @see Object#equals(Object)
*/
@Override
public boolean equals(Object obj) {
if (this == obj) // quick check
return true;
if (obj == null || getClass() != obj.getClass())
return false;
MessageFormat other = (MessageFormat) obj;
return (maxOffset == other.maxOffset
&& pattern.equals(other.pattern)
&& Objects.equals(locale,other.locale)
&& Arrays.equals(offsets,other.offsets)
&& Arrays.equals(argumentNumbers,other.argumentNumbers)
&& Arrays.equals(formats,other.formats));
}
/**
* {@return the hash code value for this {@code MessageFormat}}
*
* @implSpec This method calculates the hash code value using the value returned by
* {@link #toPattern()}.
* @see Object#hashCode()
*/
@Override
public int hashCode() {
return pattern.hashCode(); // enough for reasonable distribution
}
/**
* {@return a string identifying this {@code MessageFormat}, for debugging}
*/
@Override
public String toString() {
return
"""
MessageFormat [locale: %s, pattern: "%s"]
""".formatted(locale == null ? null : '"' + locale.getDisplayName() + '"', toPattern());
}
/**
* Defines constants that are used as attribute keys in the
* {@code AttributedCharacterIterator} returned
* from {@code MessageFormat.formatToCharacterIterator}.
*
* @since 1.4
*/
public static class Field extends Format.Field {
// Proclaim serial compatibility with 1.4 FCS
@java.io.Serial
private static final long serialVersionUID = 7899943957617360810L;
/**
* Creates a Field with the specified name.
*
* @param name Name of the attribute
*/
protected Field(String name) {
super(name);
}
/**
* Resolves instances being deserialized to the predefined constants.
*
* @throws InvalidObjectException if the constant could not be
* resolved.
* @return resolved MessageFormat.Field constant
*/
@java.io.Serial
protected Object readResolve() throws InvalidObjectException {
if (this.getClass() != MessageFormat.Field.class) {
throw new InvalidObjectException("subclass didn't correctly implement readResolve");
}
return ARGUMENT;
}
//
// The constants
//
/**
* Constant identifying a portion of a message that was generated
* from an argument passed into {@code formatToCharacterIterator}.
* The value associated with the key will be an {@code Integer}
* indicating the index in the {@code arguments} array of the
* argument from which the text was generated.
*/
public static final Field ARGUMENT =
new Field("message argument field");
}
// ===========================privates============================
/**
* The locale to use for formatting numbers and dates.
* @serial
*/
private Locale locale;
/**
* The string that the formatted values are to be plugged into. In other words, this
* is the pattern supplied on construction with all of the {} expressions taken out.
* @serial
*/
private String pattern = "";
/** The initially expected number of subformats in the format */
private static final int INITIAL_FORMATS = 10;
/**
* An array of formatters, which are used to format the arguments.
* @serial
*/
private Format[] formats = new Format[INITIAL_FORMATS];
/**
* The positions where the results of formatting each argument are to be inserted
* into the pattern.
* @serial
*/
private int[] offsets = new int[INITIAL_FORMATS];
/**
* The argument numbers corresponding to each formatter. (The formatters are stored
* in the order they occur in the pattern, not in the order in which the arguments
* are specified.)
* @serial
*/
private int[] argumentNumbers = new int[INITIAL_FORMATS];
/**
* One less than the number of entries in {@code offsets}. Can also be thought of
* as the index of the highest-numbered element in {@code offsets} that is being used.
* All of these arrays should have the same number of elements being used as {@code offsets}
* does, and so this variable suffices to tell us how many entries are in all of them.
* @serial
*/
private int maxOffset = -1;
/**
* Internal routine used by format. If {@code characterIterators} is
* {@code non-null}, AttributedCharacterIterator will be created from the
* subformats as necessary. If {@code characterIterators} is {@code null}
* and {@code fp} is {@code non-null} and identifies
* {@code Field.ARGUMENT} as the field attribute, the location of
* the first replaced argument will be set in it.
*
* @throws IllegalArgumentException if an argument in the
* {@code arguments} array is not of the type
* expected by the format element(s) that use it.
*/
private StringBuffer subformat(Object[] arguments, StringBuffer result,
FieldPosition fp, ListSynchronization
*
*
*
* Subformats that have already been created are not affected.
*
* @param locale the locale to be used when creating or comparing subformats
*/
public void setLocale(Locale locale) {
this.locale = locale;
}
/**
* Gets the locale that's used when creating or comparing subformats.
*
* @return the locale used when creating or comparing subformats
*/
public Locale getLocale() {
return locale;
}
/**
* 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
* {@linkplain ##patterns class description}.
*
* @param pattern the pattern for this message format
* @throws IllegalArgumentException if the pattern is invalid
* @throws NullPointerException if {@code pattern} is
* {@code null}
*/
public void applyPattern(String pattern) {
applyPatternImpl(pattern);
}
/**
* Implementation of applying a pattern to this MessageFormat.
* This method processes a String pattern in accordance with the MessageFormat
* pattern syntax and sets the internal {@code pattern} variable as well as
* populating the {@code formats} array with the subformats defined in the
* pattern. See the {@linkplain ##patterns} section for further understanding
* of certain special characters: "{", "}", ",". See {@linkplain
* ##makeFormat(int, int, StringBuilder[])} for the implementation of setting
* a subformat.
*/
@SuppressWarnings("fallthrough") // fallthrough in switch is expected, suppress it
private void applyPatternImpl(String pattern) {
StringBuilder[] segments = new StringBuilder[4];
// Allocate only segments[SEG_RAW] here. The rest are
// allocated on demand.
segments[SEG_RAW] = new StringBuilder();
int part = SEG_RAW;
int formatNumber = 0;
boolean inQuote = false;
int braceStack = 0;
maxOffset = -1;
for (int i = 0; i < pattern.length(); ++i) {
char ch = pattern.charAt(i);
if (part == SEG_RAW) {
if (ch == '\'') {
if (i + 1 < pattern.length()
&& pattern.charAt(i+1) == '\'') {
segments[part].append(ch); // handle doubles
++i;
} else {
inQuote = !inQuote;
}
} else if (ch == '{' && !inQuote) {
part = SEG_INDEX;
if (segments[SEG_INDEX] == null) {
segments[SEG_INDEX] = new StringBuilder();
}
} else {
segments[part].append(ch);
}
} else {
if (inQuote) { // just copy quotes in parts
segments[part].append(ch);
if (ch == '\'') {
inQuote = false;
}
} else {
switch (ch) {
case ',':
if (part < SEG_MODIFIER) {
if (segments[++part] == null) {
segments[part] = new StringBuilder();
}
} else {
segments[part].append(ch);
}
break;
case '{':
++braceStack;
segments[part].append(ch);
break;
case '}':
if (braceStack == 0) {
part = SEG_RAW;
// Set the subformat
makeFormat(i, formatNumber, segments);
formatNumber++;
// throw away other segments
segments[SEG_INDEX] = null;
segments[SEG_TYPE] = null;
segments[SEG_MODIFIER] = null;
} else {
--braceStack;
segments[part].append(ch);
}
break;
case ' ':
// Skip any leading space chars for SEG_TYPE.
if (part != SEG_TYPE || segments[SEG_TYPE].length() > 0) {
segments[part].append(ch);
}
break;
case '\'':
inQuote = true;
// fall through, so we keep quotes in other parts
default:
segments[part].append(ch);
break;
}
}
}
}
if (braceStack == 0 && part != 0) {
maxOffset = -1;
throw new IllegalArgumentException("Unmatched braces in the pattern.");
}
this.pattern = segments[0].toString();
}
/**
* 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.
*
* @implSpec The implementation in {@link MessageFormat} returns a
* string that, when passed to a {@code MessageFormat()} constructor
* or {@link #applyPattern applyPattern()}, produces an instance that
* is semantically equivalent to this instance.
*
* @return a pattern representing the current state of the message format
*/
public String toPattern() {
// later, make this more extensible
int lastOffset = 0;
StringBuilder result = new StringBuilder();
for (int i = 0; i <= maxOffset; ++i) {
copyAndFixQuotes(pattern, lastOffset, offsets[i], result);
lastOffset = offsets[i];
result.append('{').append(argumentNumbers[i]);
Format fmt = formats[i];
String subformatPattern = null;
if (fmt == null) {
// do nothing, string format
} else if (fmt instanceof NumberFormat) {
if (fmt.equals(NumberFormat.getInstance(locale))) {
result.append(",number");
} else if (fmt.equals(NumberFormat.getCurrencyInstance(locale))) {
result.append(",number,currency");
} else if (fmt.equals(NumberFormat.getPercentInstance(locale))) {
result.append(",number,percent");
} else if (fmt.equals(NumberFormat.getIntegerInstance(locale))) {
result.append(",number,integer");
} else {
if (fmt instanceof DecimalFormat dfmt) {
result.append(",number");
subformatPattern = dfmt.toPattern();
} else if (fmt instanceof ChoiceFormat cfmt) {
result.append(",choice");
subformatPattern = cfmt.toPattern();
} else {
// UNKNOWN
}
}
} else if (fmt instanceof DateFormat) {
int index;
for (index = MODIFIER_DEFAULT; index < DATE_TIME_MODIFIERS.length; index++) {
DateFormat df = DateFormat.getDateInstance(DATE_TIME_MODIFIERS[index],
locale);
if (fmt.equals(df)) {
result.append(",date");
break;
}
df = DateFormat.getTimeInstance(DATE_TIME_MODIFIERS[index],
locale);
if (fmt.equals(df)) {
result.append(",time");
break;
}
}
if (index >= DATE_TIME_MODIFIERS.length) {
if (fmt instanceof SimpleDateFormat sdfmt) {
result.append(",date");
subformatPattern = sdfmt.toPattern();
} else {
// UNKNOWN
}
} else if (index != MODIFIER_DEFAULT) {
result.append(',').append(DATE_TIME_MODIFIER_KEYWORDS[index]);
}
} else {
//result.append(", unknown");
}
if (subformatPattern != null) {
result.append(',');
// The subformat pattern comes already quoted, but only for those characters that are
// special to the subformat. Therefore, we may need to quote additional characters.
// The ones we care about at the MessageFormat level are '{' and '}'.
copyAndQuoteBraces(subformatPattern, result);
}
result.append('}');
}
copyAndFixQuotes(pattern, lastOffset, pattern.length(), result);
return result.toString();
}
/**
* Sets the formats to use for the values passed into
* {@code format} methods or returned from {@code parse}
* methods. The indices of elements in {@code newFormats}
* correspond to the argument indices used in the previously set
* pattern string.
* The order of formats in {@code newFormats} thus corresponds to
* the order of elements in the {@code arguments} array passed
* to the {@code format} methods or the result array returned
* by the {@code parse} methods.
*
*
*
*
*
*
*
* Subformat
* Argument
* Formatted Text
*
* any
* unavailable
* "{" + argumentIndex + "}"
*
* {@code null}
* {@code "null"}
*
* {@code instanceof ChoiceFormat}
* any
* subformat.format(argument).indexOf('{') >= 0 ?
*
* (new MessageFormat(subformat.format(argument), getLocale())).format(argument) :
* subformat.format(argument)
* {@code != null}
* any
* {@code subformat.format(argument)}
*
* {@code null}
* {@code instanceof Number}
* {@code NumberFormat.getInstance(getLocale()).format(argument)}
*
* {@code instanceof Date}
* {@code DateFormat.getDateTimeInstance(DateFormat.SHORT, DateFormat.SHORT, getLocale()).format(argument)}
*
* {@code instanceof String}
* {@code argument}
*
*
* any
* {@code argument.toString()}
*
*
*
* @param pattern the pattern string
* @param arguments object(s) to format
* @return the formatted string
* @throws IllegalArgumentException if the pattern is invalid,
* or if an argument in the {@code arguments} array
* is not of the type expected by the format element(s)
* that use it.
* @throws NullPointerException if {@code pattern} is {@code null}
*/
public static String format(String pattern, Object ... arguments) {
MessageFormat temp = new MessageFormat(pattern);
return temp.format(arguments);
}
// Overrides
/**
* Formats an array of objects and appends the {@code MessageFormat}'s
* pattern, with format elements replaced by the formatted objects, to the
* provided {@code StringBuffer}.
* This is equivalent to
* (new {@link #MessageFormat(String) MessageFormat}(pattern)).{@link #format(java.lang.Object[], java.lang.StringBuffer, java.text.FieldPosition) format}(arguments, new StringBuffer(), null).toString()
*
*
*
* @param arguments an array of objects to be formatted and substituted.
* @param result where text is appended.
* @param pos keeps track on the position of the first replaced argument
* in the output string.
* @throws IllegalArgumentException if an argument in the
* {@code arguments} array is not of the type
* expected by the format element(s) that use it.
* @throws NullPointerException if {@code result} is {@code null} or
* if the {@code MessageFormat} instance that calls this method
* has locale set to null, and the implementation
* uses a locale-dependent subformat.
*/
public final StringBuffer format(Object arguments, StringBuffer result,
FieldPosition pos)
{
return subformat((Object[]) arguments, result, pos, null);
}
/**
* Formats an array of objects and inserts them into the
* {@code MessageFormat}'s pattern, producing an
* {@code AttributedCharacterIterator}.
* You can use the returned {@code AttributedCharacterIterator}
* to build the resulting String, as well as to determine information
* about the resulting String.
* {@link #format(java.lang.Object[], java.lang.StringBuffer, java.text.FieldPosition) format}((Object[]) arguments, result, pos)
*
*
* {@link #format(java.lang.Object[], java.lang.StringBuffer, java.text.FieldPosition) format}(arguments, new StringBuffer(), null).toString()
*
*
* When the parse fails, use ParsePosition.getErrorIndex() to find out
* where in the string 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.
*
* @param source the string to parse
* @param pos the parse position
* @return an array of parsed objects
* @throws NullPointerException if {@code pos} is {@code null}
* for a non-null {@code source} string.
*/
public Object[] parse(String source, ParsePosition pos) {
if (source == null) {
Object[] empty = {};
return empty;
}
int maximumArgumentNumber = -1;
for (int i = 0; i <= maxOffset; i++) {
if (argumentNumbers[i] > maximumArgumentNumber) {
maximumArgumentNumber = argumentNumbers[i];
}
}
Object[] resultArray = new Object[maximumArgumentNumber + 1];
int patternOffset = 0;
int sourceOffset = pos.index;
ParsePosition tempStatus = new ParsePosition(0);
for (int i = 0; i <= maxOffset; ++i) {
// match up to format
int len = offsets[i] - patternOffset;
if (len == 0 || pattern.regionMatches(patternOffset,
source, sourceOffset, len)) {
sourceOffset += len;
patternOffset += len;
} else {
pos.errorIndex = sourceOffset;
return null; // leave index as is to signal error
}
// now use format
if (formats[i] == null) { // string format
// if at end, use longest possible match
// otherwise uses first match to intervening string
// does NOT recursively try all possibilities
int tempLength = (i != maxOffset) ? offsets[i+1] : pattern.length();
int next;
if (patternOffset >= tempLength) {
next = source.length();
}else{
next = source.indexOf(pattern.substring(patternOffset, tempLength),
sourceOffset);
}
if (next < 0) {
pos.errorIndex = sourceOffset;
return null; // leave index as is to signal error
} else {
String strValue= source.substring(sourceOffset,next);
if (!strValue.equals("{"+argumentNumbers[i]+"}"))
resultArray[argumentNumbers[i]]
= source.substring(sourceOffset,next);
sourceOffset = next;
}
} else {
tempStatus.index = sourceOffset;
resultArray[argumentNumbers[i]]
= formats[i].parseObject(source,tempStatus);
if (tempStatus.index == sourceOffset) {
pos.errorIndex = sourceOffset;
return null; // leave index as is to signal error
}
sourceOffset = tempStatus.index; // update
}
}
int len = pattern.length() - patternOffset;
if (len == 0 || pattern.regionMatches(patternOffset,
source, sourceOffset, len)) {
pos.index = sourceOffset + len;
} else {
pos.errorIndex = sourceOffset;
return null; // leave index as is to signal error
}
return resultArray;
}
/**
* 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.
*