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MessageFormat.javaAPI DocJava SE 5 API63409Fri Aug 26 14:57:20 BST 2005java.text

MessageFormat

public class MessageFormat extends Format
MessageFormat provides a means to produce concatenated messages in language-neutral way. Use this to construct messages displayed for end users.

MessageFormat takes a set of objects, formats them, then inserts the formatted strings into the pattern at the appropriate places.

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 as well as the subformats used for inserted arguments.

Patterns and Their Interpretation

MessageFormat uses patterns of the following form:
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

String:
StringPartopt
String StringPart

StringPart:
''
' QuotedString '
UnquotedString

SubformatPattern:
SubformatPatternPartopt
SubformatPattern SubformatPatternPart

SubFormatPatternPart:
' QuotedPattern '
UnquotedPattern

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.

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) (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)

Usage Information

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 MessageFormat.format, which internally creates a MessageFormat for one-time use:

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 MessageFormat instance that can be used repeatedly:

int fileCount = 1273;
String diskName = "MyDisk";
Object[] testArgs = {new Long(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 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, you can use a ChoiceFormat to produce correct forms for singular and plural:

MessageFormat form = new MessageFormat("The disk \"{1}\" contains {0}.");
double[] filelimits = {0,1,2};
String[] filepart = {"no files","one file","{0,number} files"};
ChoiceFormat fileform = new ChoiceFormat(filelimits, filepart);
form.setFormatByArgumentIndex(0, fileform);

int fileCount = 1273;
String diskName = "MyDisk";
Object[] testArgs = {new Long(fileCount), diskName};

System.out.println(form.format(testArgs));
The output with different values for fileCount:
The disk "MyDisk" contains no files.
The disk "MyDisk" contains one file.
The disk "MyDisk" contains 1,273 files.

You can create the ChoiceFormat programmatically, as in the above example, or by using a pattern. See {@link ChoiceFormat} for more information.

form.applyPattern(
"There {0,choice,0#are no files|1#is one file|1<are {0,number,integer} files}.");

Note: As we see above, the string produced by a ChoiceFormat in MessageFormat is treated specially; occurences of '{' are used to indicated subformats, and cause recursion. If you create both a MessageFormat and ChoiceFormat programmatically (instead of using the string patterns), then be careful not to produce a format that recurses on itself, which will cause an infinite loop.

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,

MessageFormat mf = new MessageFormat("{0,number,#.##}, {0,number,#.#}");
Object[] objs = {new Double(3.1415)};
String result = mf.format( objs );
// result now equals "3.14, 3.1"
objs = null;
objs = mf.parse(result, new ParsePosition(0));
// objs now equals {new Double(3.1)}

Likewise, parsing with a MessageFormat object using patterns containing multiple occurences of the same argument would return the last match. For example,

MessageFormat mf = new MessageFormat("{0}, {0}, {0}");
String forParsing = "x, y, z";
Object[] objs = mf.parse(forParsing, new ParsePosition(0));
// result now equals {new String("z")}

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.

see
java.util.Locale
see
Format
see
NumberFormat
see
DecimalFormat
see
ChoiceFormat
version
1.56, 12/19/03
author
Mark Davis

Fields Summary
private static final long
serialVersionUID
private Locale
locale
The locale to use for formatting numbers and dates.
private String
pattern
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.
private static final int
INITIAL_FORMATS
The initially expected number of subformats in the format
private Format[]
formats
An array of formatters, which are used to format the arguments.
private int[]
offsets
The positions where the results of formatting each argument are to be inserted into the pattern.
private int[]
argumentNumbers
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.)
private int
maxOffset
One less than the number of entries in offsets. Can also be thought of as the index of the highest-numbered element in offsets that is being used. All of these arrays should have the same number of elements being used as offsets does, and so this variable suffices to tell us how many entries are in all of them.
private static final String[]
typeList
private static final String[]
modifierList
private static final String[]
dateModifierList
Constructors Summary
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.

param
pattern the pattern for this message format
exception
IllegalArgumentException if the pattern is invalid


                                                                     
       
        this.locale = Locale.getDefault();
        applyPattern(pattern);
    
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.

param
pattern the pattern for this message format
param
locale the locale for this message format
exception
IllegalArgumentException if the pattern is invalid
since
1.4

        this.locale = locale;
        applyPattern(pattern);
    
Methods Summary
private voidappend(java.lang.StringBuffer result, java.text.CharacterIterator iterator)
Convenience method to append all the characters in iterator to the StringBuffer result.

        if (iterator.first() != CharacterIterator.DONE) {
            char aChar;

            result.append(iterator.first());
            while ((aChar = iterator.next()) != CharacterIterator.DONE) {
                result.append(aChar);
            }
        }
    
public voidapplyPattern(java.lang.String pattern)
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.

param
pattern the pattern for this message format
exception
IllegalArgumentException if the pattern is invalid

            StringBuffer[] segments = new StringBuffer[4];
            for (int i = 0; i < segments.length; ++i) {
                segments[i] = new StringBuffer();
            }
            int part = 0;
            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 == 0) {
                    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 = 1;
                    } 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 < 3)
                            part += 1;
                        else
                            segments[part].append(ch);
                        break;
                    case '{":
                        ++braceStack;
                        segments[part].append(ch);
                        break;
                    case '}":
                        if (braceStack == 0) {
                            part = 0;
                            makeFormat(i, formatNumber, segments);
                            formatNumber++;
                        } else {
                            --braceStack;
                            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();
    
public java.lang.Objectclone()
Creates and returns a copy of this object.

return
a clone of this instance.

        MessageFormat other = (MessageFormat) super.clone();

        // clone arrays. Can't do with utility because of bug in Cloneable
        other.formats = (Format[]) 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 = (int[]) offsets.clone();
        other.argumentNumbers = (int[]) argumentNumbers.clone();

        return other;
    
private static final voidcopyAndFixQuotes(java.lang.String source, int start, int end, java.lang.StringBuffer target)

        for (int i = start; i < end; ++i) {
            char ch = source.charAt(i);
            if (ch == '{") {
                target.append("'{'");
            } else if (ch == '}") {
                target.append("'}'");
            } else if (ch == '\'") {
                target.append("''");
            } else {
                target.append(ch);
            }
        }
    
public booleanequals(java.lang.Object obj)
Equality comparison between two message format objects

        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)
            && Utility.objectEquals(locale, other.locale)   // does null check
                && Utility.arrayEquals(offsets,other.offsets)
            && Utility.arrayEquals(argumentNumbers,other.argumentNumbers)
            && Utility.arrayEquals(formats,other.formats));
    
private static final intfindKeyword(java.lang.String s, java.lang.String[] list)

        s = s.trim().toLowerCase();
        for (int i = 0; i < list.length; ++i) {
            if (s.equals(list[i]))
                return i;
        }
        return -1;
    
public final java.lang.StringBufferformat(java.lang.Object[] arguments, java.lang.StringBuffer result, java.text.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.

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.

param
arguments an array of objects to be formatted and substituted.
param
result where text is appended.
param
pos On input: an alignment field, if desired. On output: the offsets of the alignment field.
exception
IllegalArgumentException if an argument in the arguments array is not of the type expected by the format element(s) that use it.

        return subformat(arguments, result, pos, null);
    
public static java.lang.Stringformat(java.lang.String pattern, java.lang.Object arguments)
Creates a MessageFormat with the given pattern and uses it to format the given arguments. 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()

exception
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.

        MessageFormat temp = new MessageFormat(pattern);
        return temp.format(arguments);
    
public final java.lang.StringBufferformat(java.lang.Object arguments, java.lang.StringBuffer result, java.text.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. This is equivalent to
{@link #format(java.lang.Object[], java.lang.StringBuffer, java.text.FieldPosition) format}((Object[]) arguments, result, pos)

param
arguments an array of objects to be formatted and substituted.
param
result where text is appended.
param
pos On input: an alignment field, if desired. On output: the offsets of the alignment field.
exception
IllegalArgumentException if an argument in the arguments array is not of the type expected by the format element(s) that use it.

        return subformat((Object[]) arguments, result, pos, null);
    
public java.text.AttributedCharacterIteratorformatToCharacterIterator(java.lang.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

{@link #format(java.lang.Object[], java.lang.StringBuffer, java.text.FieldPosition) 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.

param
arguments an array of objects to be formatted and substituted.
return
AttributedCharacterIterator describing the formatted value.
exception
NullPointerException if arguments is null.
exception
IllegalArgumentException if an argument in the arguments array is not of the type expected by the format element(s) that use it.
since
1.4

        StringBuffer result = new StringBuffer();
        ArrayList iterators = new ArrayList();

        if (arguments == null) {
            throw new NullPointerException(
                   "formatToCharacterIterator must be passed non-null object");
        }
        subformat((Object[]) arguments, result, null, iterators);
        if (iterators.size() == 0) {
            return createAttributedCharacterIterator("");
        }
        return createAttributedCharacterIterator(
                     (AttributedCharacterIterator[])iterators.toArray(
                     new AttributedCharacterIterator[iterators.size()]));
    
public java.text.Format[]getFormats()
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 arguments array passed to the format methods or the result array returned by the parse methods.

return
the formats used for the format elements in the pattern

        Format[] resultArray = new Format[maxOffset + 1];
        System.arraycopy(formats, 0, resultArray, 0, maxOffset + 1);
        return resultArray;
    
public java.text.Format[]getFormatsByArgumentIndex()
Gets 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.

return
the formats used for the arguments within the pattern
since
1.4

        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;
    
public java.util.LocalegetLocale()
Gets the locale that's used when creating or comparing subformats.

return
the locale used when creating or comparing subformats

        return locale;
    
public inthashCode()
Generates a hash code for the message format object.

        return pattern.hashCode(); // enough for reasonable distribution
    
private voidmakeFormat(int position, int offsetNumber, java.lang.StringBuffer[] segments)


         
                             
    
        // get the argument number
        int argumentNumber;
        try {
            argumentNumber = Integer.parseInt(segments[1].toString()); // always unlocalized!
        } catch (NumberFormatException e) {
            throw new IllegalArgumentException("can't parse argument number " + segments[1]);
        }
        if (argumentNumber < 0) {
            throw new IllegalArgumentException("negative argument number " + argumentNumber);
        }

        // resize format information arrays if necessary
        if (offsetNumber >= formats.length) {
            int newLength = formats.length * 2;
            Format[] newFormats = new Format[newLength];
            int[] newOffsets = new int[newLength];
            int[] newArgumentNumbers = new int[newLength];
            System.arraycopy(formats, 0, newFormats, 0, maxOffset + 1);
            System.arraycopy(offsets, 0, newOffsets, 0, maxOffset + 1);
            System.arraycopy(argumentNumbers, 0, newArgumentNumbers, 0, maxOffset + 1);
            formats = newFormats;
            offsets = newOffsets;
            argumentNumbers = newArgumentNumbers;
        }
        int oldMaxOffset = maxOffset;
        maxOffset = offsetNumber;
        offsets[offsetNumber] = segments[0].length();
        argumentNumbers[offsetNumber] = argumentNumber;

        // now get the format
        Format newFormat = null;
        switch (findKeyword(segments[2].toString(), typeList)) {
        case 0:
            break;
        case 1: case 2:// number
            switch (findKeyword(segments[3].toString(), modifierList)) {
            case 0: // default;
                newFormat = NumberFormat.getInstance(locale);
                break;
            case 1: case 2:// currency
                newFormat = NumberFormat.getCurrencyInstance(locale);
                break;
            case 3: case 4:// percent
                newFormat = NumberFormat.getPercentInstance(locale);
                break;
            case 5: case 6:// integer
                newFormat = NumberFormat.getIntegerInstance(locale);
                break;
            default: // pattern
                newFormat = new DecimalFormat(segments[3].toString(), new DecimalFormatSymbols(locale));
                break;
            }
            break;
        case 3: case 4: // date
            switch (findKeyword(segments[3].toString(), dateModifierList)) {
            case 0: // default
                newFormat = DateFormat.getDateInstance(DateFormat.DEFAULT, locale);
                break;
            case 1: case 2: // short
                newFormat = DateFormat.getDateInstance(DateFormat.SHORT, locale);
                break;
            case 3: case 4: // medium
                newFormat = DateFormat.getDateInstance(DateFormat.DEFAULT, locale);
                break;
            case 5: case 6: // long
                newFormat = DateFormat.getDateInstance(DateFormat.LONG, locale);
                break;
            case 7: case 8: // full
                newFormat = DateFormat.getDateInstance(DateFormat.FULL, locale);
                break;
            default:
                newFormat = new SimpleDateFormat(segments[3].toString(), locale);
                break;
            }
            break;
        case 5: case 6:// time
            switch (findKeyword(segments[3].toString(), dateModifierList)) {
            case 0: // default
                newFormat = DateFormat.getTimeInstance(DateFormat.DEFAULT, locale);
                break;
            case 1: case 2: // short
                newFormat = DateFormat.getTimeInstance(DateFormat.SHORT, locale);
                break;
            case 3: case 4: // medium
                newFormat = DateFormat.getTimeInstance(DateFormat.DEFAULT, locale);
                break;
            case 5: case 6: // long
                newFormat = DateFormat.getTimeInstance(DateFormat.LONG, locale);
                break;
            case 7: case 8: // full
                newFormat = DateFormat.getTimeInstance(DateFormat.FULL, locale);
                break;
            default:
                newFormat = new SimpleDateFormat(segments[3].toString(), locale);
                break;
            }
            break;
        case 7: case 8:// choice
            try {
                newFormat = new ChoiceFormat(segments[3].toString());
            } catch (Exception e) {
                maxOffset = oldMaxOffset;
                throw new IllegalArgumentException(
                                         "Choice Pattern incorrect");
            }
            break;
        default:
            maxOffset = oldMaxOffset;
            throw new IllegalArgumentException("unknown format type at ");
        }
        formats[offsetNumber] = newFormat;
        segments[1].setLength(0);   // throw away other segments
        segments[2].setLength(0);
        segments[3].setLength(0);
    
public java.lang.Object[]parse(java.lang.String source, java.text.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.

        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;
    
public java.lang.Object[]parse(java.lang.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 {@link #parse(String, ParsePosition)} method for more information on message parsing.

param
source A String whose beginning should be parsed.
return
An Object array parsed from the string.
exception
ParseException if the beginning of the specified string cannot be parsed.

        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;
    
public java.lang.ObjectparseObject(java.lang.String source, java.text.ParsePosition pos)
Parses text from a string to produce an object array.

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 {@link #parse(String, ParsePosition)} method for more information on message parsing.

param
source A String, part of which should be parsed.
param
pos A ParsePosition object with index and error index information as described above.
return
An Object array parsed from the string. In case of error, returns null.
exception
NullPointerException if pos is null.

        return parse(source, pos);
    
private voidreadObject(java.io.ObjectInputStream in)
After reading an object from the input stream, do a simple verification to maintain class invariants.

throws
InvalidObjectException if the objects read from the stream is invalid.

        in.defaultReadObject();
        boolean isValid = maxOffset >= -1
                && formats.length > maxOffset
                && offsets.length > maxOffset
                && argumentNumbers.length > maxOffset;
        if (isValid) {
            int lastOffset = pattern.length() + 1;
            for (int i = maxOffset; i >= 0; --i) {
                if ((offsets[i] < 0) || (offsets[i] > lastOffset)) {
                    isValid = false;
                    break;
                } else {
                    lastOffset = offsets[i];
                }
            }
        }
        if (!isValid) {
            throw new InvalidObjectException("Could not reconstruct MessageFormat from corrupt stream.");
        }
    
public voidsetFormat(int formatElementIndex, java.text.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 {@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
exception
ArrayIndexOutOfBoundsException if formatElementIndex is equal to or larger than the number of format elements in the pattern string

        formats[formatElementIndex] = newFormat;
    
public voidsetFormatByArgumentIndex(int argumentIndex, java.text.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.

param
argumentIndex the argument index for which to use the new format
param
newFormat the new format to use
since
1.4

        for (int j = 0; j <= maxOffset; j++) {
            if (argumentNumbers[j] == argumentIndex) {
                formats[j] = newFormat;
            }
        }
    
public voidsetFormats(java.text.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 {@link #setFormatsByArgumentIndex 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.

param
newFormats the new formats to use
exception
NullPointerException if newFormats is null

        int runsToCopy = newFormats.length;
        if (runsToCopy > maxOffset + 1) {
            runsToCopy = maxOffset + 1;
        }
        for (int i = 0; i < runsToCopy; i++) {
            formats[i] = newFormats[i];
        }
    
public voidsetFormatsByArgumentIndex(java.text.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.

param
newFormats the new formats to use
exception
NullPointerException if newFormats is null
since
1.4

        for (int i = 0; i <= maxOffset; i++) {
            int j = argumentNumbers[i];
            if (j < newFormats.length) {
                formats[i] = newFormats[j];
            }
        }
    
public voidsetLocale(java.util.Locale locale)
Sets the locale to be used when creating or comparing subformats. This affects subsequent calls to the {@link #applyPattern applyPattern} and {@link #toPattern toPattern} methods as well as to the format and {@link #formatToCharacterIterator formatToCharacterIterator} methods.

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

        this.locale = locale;
    
private java.lang.StringBuffersubformat(java.lang.Object[] arguments, java.lang.StringBuffer result, java.text.FieldPosition fp, java.util.List characterIterators)
Internal routine used by format. If characterIterators is non-null, AttributedCharacterIterator will be created from the subformats as necessary. If characterIterators is null and fp is non-null and identifies Field.MESSAGE_ARGUMENT, the location of the first replaced argument will be set in it.

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


                                                                                              
         
                                       
        // note: this implementation assumes a fast substring & index.
        // if this is not true, would be better to append chars one by one.
        int lastOffset = 0;
        int last = result.length();
        for (int i = 0; i <= maxOffset; ++i) {
            result.append(pattern.substring(lastOffset, offsets[i]));
            lastOffset = offsets[i];
            int argumentNumber = argumentNumbers[i];
            if (arguments == null || argumentNumber >= arguments.length) {
                result.append("{" + argumentNumber + "}");
                continue;
            }
            // int argRecursion = ((recursionProtection >> (argumentNumber*2)) & 0x3);
            if (false) { // if (argRecursion == 3){
                // prevent loop!!!
                result.append('\uFFFD");
            } else {
                Object obj = arguments[argumentNumber];
                String arg = null;
                Format subFormatter = null;
                if (obj == null) {
                    arg = "null";
                } else if (formats[i] != null) {
                    subFormatter = formats[i];
                    if (subFormatter instanceof ChoiceFormat) {
                        arg = formats[i].format(obj);
                        if (arg.indexOf('{") >= 0) {
                            subFormatter = new MessageFormat(arg, locale);
                            obj = arguments;
                            arg = null;
                        }
                    }
                } else if (obj instanceof Number) {
                    // format number if can
                    subFormatter = NumberFormat.getInstance(locale);
                } else if (obj instanceof Date) {
                    // format a Date if can
                    subFormatter = DateFormat.getDateTimeInstance(
                             DateFormat.SHORT, DateFormat.SHORT, locale);//fix
                } else if (obj instanceof String) {
                    arg = (String) obj;

                } else {
                    arg = obj.toString();
                    if (arg == null) arg = "null";
                }

                // At this point we are in two states, either subFormatter
                // is non-null indicating we should format obj using it,
                // or arg is non-null and we should use it as the value.

                if (characterIterators != null) {
                    // If characterIterators is non-null, it indicates we need
                    // to get the CharacterIterator from the child formatter.
                    if (last != result.length()) {
                        characterIterators.add(
                            createAttributedCharacterIterator(result.substring
                                                              (last)));
                        last = result.length();
                    }
                    if (subFormatter != null) {
                        AttributedCharacterIterator subIterator =
                                   subFormatter.formatToCharacterIterator(obj);

                        append(result, subIterator);
                        if (last != result.length()) {
                            characterIterators.add(
                                         createAttributedCharacterIterator(
                                         subIterator, Field.ARGUMENT,
                                         new Integer(argumentNumber)));
                            last = result.length();
                        }
                        arg = null;
                    }
                    if (arg != null && arg.length() > 0) {
                        result.append(arg);
                        characterIterators.add(
                                 createAttributedCharacterIterator(
                                 arg, Field.ARGUMENT,
                                 new Integer(argumentNumber)));
                        last = result.length();
                    }
                }
                else {
                    if (subFormatter != null) {
                        arg = subFormatter.format(obj);
                    }
                    last = result.length();
                    result.append(arg);
                    if (i == 0 && fp != null && Field.ARGUMENT.equals(
                                  fp.getFieldAttribute())) {
                        fp.setBeginIndex(last);
                        fp.setEndIndex(result.length());
                    }
                    last = result.length();
                }
            }
        }
        result.append(pattern.substring(lastOffset, pattern.length()));
        if (characterIterators != null && last != result.length()) {
            characterIterators.add(createAttributedCharacterIterator(
                                   result.substring(last)));
        }
        return result;
    
public java.lang.StringtoPattern()
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.

return
a pattern representing the current state of the message format

        // later, make this more extensible
        int lastOffset = 0;
        StringBuffer result = new StringBuffer();
        for (int i = 0; i <= maxOffset; ++i) {
            copyAndFixQuotes(pattern, lastOffset, offsets[i],result);
            lastOffset = offsets[i];
            result.append('{");
            result.append(argumentNumbers[i]);
            if (formats[i] == null) {
                // do nothing, string format
            } else if (formats[i] instanceof DecimalFormat) {
                if (formats[i].equals(NumberFormat.getInstance(locale))) {
                    result.append(",number");
                } else if (formats[i].equals(NumberFormat.getCurrencyInstance(locale))) {
                    result.append(",number,currency");
                } else if (formats[i].equals(NumberFormat.getPercentInstance(locale))) {
                    result.append(",number,percent");
                } else if (formats[i].equals(NumberFormat.getIntegerInstance(locale))) {
                    result.append(",number,integer");
                } else {
                    result.append(",number," +
                                  ((DecimalFormat)formats[i]).toPattern());
                }
            } else if (formats[i] instanceof SimpleDateFormat) {
                if (formats[i].equals(DateFormat.getDateInstance(
                                                               DateFormat.DEFAULT,locale))) {
                    result.append(",date");
                } else if (formats[i].equals(DateFormat.getDateInstance(
                                                                      DateFormat.SHORT,locale))) {
                    result.append(",date,short");
                } else if (formats[i].equals(DateFormat.getDateInstance(
                                                                      DateFormat.DEFAULT,locale))) {
                    result.append(",date,medium");
                } else if (formats[i].equals(DateFormat.getDateInstance(
                                                                      DateFormat.LONG,locale))) {
                    result.append(",date,long");
                } else if (formats[i].equals(DateFormat.getDateInstance(
                                                                      DateFormat.FULL,locale))) {
                    result.append(",date,full");
                } else if (formats[i].equals(DateFormat.getTimeInstance(
                                                                      DateFormat.DEFAULT,locale))) {
                    result.append(",time");
                } else if (formats[i].equals(DateFormat.getTimeInstance(
                                                                      DateFormat.SHORT,locale))) {
                    result.append(",time,short");
                } else if (formats[i].equals(DateFormat.getTimeInstance(
                                                                      DateFormat.DEFAULT,locale))) {
                    result.append(",time,medium");
                } else if (formats[i].equals(DateFormat.getTimeInstance(
                                                                      DateFormat.LONG,locale))) {
                    result.append(",time,long");
                } else if (formats[i].equals(DateFormat.getTimeInstance(
                                                                      DateFormat.FULL,locale))) {
                    result.append(",time,full");
                } else {
                    result.append(",date,"
                                  + ((SimpleDateFormat)formats[i]).toPattern());
                }
            } else if (formats[i] instanceof ChoiceFormat) {
                result.append(",choice,"
                              + ((ChoiceFormat)formats[i]).toPattern());
            } else {
                //result.append(", unknown");
            }
            result.append('}");
        }
        copyAndFixQuotes(pattern, lastOffset, pattern.length(), result);
        return result.toString();