JDK8/Java8源码在线阅读
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/*
* (C) Copyright Taligent, Inc. 1996, 1997 - All Rights Reserved
* (C) Copyright IBM Corp. 1996 - 1998 - All Rights Reserved
*
* The original version of this source code and documentation is copyrighted
* and owned by Taligent, Inc., a wholly-owned subsidiary of IBM. These
* materials are provided under terms of a License Agreement between Taligent
* and Sun. This technology is protected by multiple US and International
* patents. This notice and attribution to Taligent may not be removed.
* Taligent is a registered trademark of Taligent, Inc.
*
*/
package java.text;
import java.io.InvalidObjectException;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.text.DecimalFormat;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Date;
import java.util.List;
import java.util.Locale;
/**
* <code>MessageFormat</code> provides a means to produce concatenated
* messages in a language-neutral way. Use this to construct messages
* displayed for end users.
*
* <p>
* <code>MessageFormat</code> takes a set of objects, formats them, then
* inserts the formatted strings into the pattern at the appropriate places.
*
* <p>
* <strong>Note:</strong>
* <code>MessageFormat</code> differs from the other <code>Format</code>
* classes in that you create a <code>MessageFormat</code> object with one
* of its constructors (not with a <code>getInstance</code> style factory
* method). The factory methods aren't necessary because <code>MessageFormat</code>
* 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.
*
* <h3><a name="patterns">Patterns and Their Interpretation</a></h3>
*
* <code>MessageFormat</code> uses patterns of the following form:
* <blockquote><pre>
* <i>MessageFormatPattern:</i>
* <i>String</i>
* <i>MessageFormatPattern</i> <i>FormatElement</i> <i>String</i>
*
* <i>FormatElement:</i>
* { <i>ArgumentIndex</i> }
* { <i>ArgumentIndex</i> , <i>FormatType</i> }
* { <i>ArgumentIndex</i> , <i>FormatType</i> , <i>FormatStyle</i> }
*
* <i>FormatType: one of </i>
* number date time choice
*
* <i>FormatStyle:</i>
* short
* medium
* long
* full
* integer
* currency
* percent
* <i>SubformatPattern</i>
* </pre></blockquote>
*
* <p>Within a <i>String</i>, a pair of single quotes can be used to
* quote any arbitrary characters except single quotes. For example,
* pattern string <code>"'{0}'"</code> represents string
* <code>"{0}"</code>, not a <i>FormatElement</i>. A single quote itself
* must be represented by doubled single quotes {@code ''} throughout a
* <i>String</i>. For example, pattern string <code>"'{''}'"</code> is
* interpreted as a sequence of <code>'{</code> (start of quoting and a
* left curly brace), <code>''</code> (a single quote), and
* <code>}'</code> (a right curly brace and end of quoting),
* <em>not</em> <code>'{'</code> and <code>'}'</code> (quoted left and
* right curly braces): representing string <code>"{'}"</code>,
* <em>not</em> <code>"{}"</code>.
*
* <p>A <i>SubformatPattern</i> is interpreted by its corresponding
* subformat, and subformat-dependent pattern rules apply. For example,
* pattern string <code>"{1,number,<u>$'#',##</u>}"</code>
* (<i>SubformatPattern</i> with underline) will produce a number format
* with the pound-sign quoted, with a result such as: {@code
* "$#31,45"}. Refer to each {@code Format} subclass documentation for
* details.
*
* <p>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}'"}.
*
* <p>Any curly braces within an unquoted pattern must be balanced. For
* example, <code>"ab {0} de"</code> and <code>"ab '}' de"</code> are
* valid patterns, but <code>"ab {0'}' de"</code>, <code>"ab } de"</code>
* and <code>"''{''"</code> are not.
*
* <dl><dt><b>Warning:</b><dd>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 {@code MessageFormat}.
* Note that localizers may need to use single quotes in translated
* strings where the original version doesn't have them.
* </dl>
* <p>
* The <i>ArgumentIndex</i> 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.
* <p>
* The <i>FormatType</i> and <i>FormatStyle</i> 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 <i>SubformatPattern</i> must
* be a valid pattern string for the {@code Format} subclass used.
*
* <table border=1 summary="Shows how FormatType and FormatStyle values map to Format instances">
* <tr>
* <th id="ft" class="TableHeadingColor">FormatType
* <th id="fs" class="TableHeadingColor">FormatStyle
* <th id="sc" class="TableHeadingColor">Subformat Created
* <tr>
* <td headers="ft"><i>(none)</i>
* <td headers="fs"><i>(none)</i>
* <td headers="sc"><code>null</code>
* <tr>
* <td headers="ft" rowspan=5><code>number</code>
* <td headers="fs"><i>(none)</i>
* <td headers="sc">{@link NumberFormat#getInstance(Locale) NumberFormat.getInstance}{@code (getLocale())}
* <tr>
* <td headers="fs"><code>integer</code>
* <td headers="sc">{@link NumberFormat#getIntegerInstance(Locale) NumberFormat.getIntegerInstance}{@code (getLocale())}
* <tr>
* <td headers="fs"><code>currency</code>
* <td headers="sc">{@link NumberFormat#getCurrencyInstance(Locale) NumberFormat.getCurrencyInstance}{@code (getLocale())}
* <tr>
* <td headers="fs"><code>percent</code>
* <td headers="sc">{@link NumberFormat#getPercentInstance(Locale) NumberFormat.getPercentInstance}{@code (getLocale())}
* <tr>
* <td headers="fs"><i>SubformatPattern</i>
* <td headers="sc">{@code new} {@link DecimalFormat#DecimalFormat(String,DecimalFormatSymbols) DecimalFormat}{@code (subformatPattern,} {@link DecimalFormatSymbols#getInstance(Locale) DecimalFormatSymbols.getInstance}{@code (getLocale()))}
* <tr>
* <td headers="ft" rowspan=6><code>date</code>
* <td headers="fs"><i>(none)</i>
* <td headers="sc">{@link DateFormat#getDateInstance(int,Locale) DateFormat.getDateInstance}{@code (}{@link DateFormat#DEFAULT}{@code , getLocale())}
* <tr>
* <td headers="fs"><code>short</code>
* <td headers="sc">{@link DateFormat#getDateInstance(int,Locale) DateFormat.getDateInstance}{@code (}{@link DateFormat#SHORT}{@code , getLocale())}
* <tr>
* <td headers="fs"><code>medium</code>
* <td headers="sc">{@link DateFormat#getDateInstance(int,Locale) DateFormat.getDateInstance}{@code (}{@link DateFormat#DEFAULT}{@code , getLocale())}
* <tr>
* <td headers="fs"><code>long</code>
* <td headers="sc">{@link DateFormat#getDateInstance(int,Locale) DateFormat.getDateInstance}{@code (}{@link DateFormat#LONG}{@code , getLocale())}
* <tr>
* <td headers="fs"><code>full</code>
* <td headers="sc">{@link DateFormat#getDateInstance(int,Locale) DateFormat.getDateInstance}{@code (}{@link DateFormat#FULL}{@code , getLocale())}
* <tr>
* <td headers="fs"><i>SubformatPattern</i>
* <td headers="sc">{@code new} {@link SimpleDateFormat#SimpleDateFormat(String,Locale) SimpleDateFormat}{@code (subformatPattern, getLocale())}
* <tr>
* <td headers="ft" rowspan=6><code>time</code>
* <td headers="fs"><i>(none)</i>
* <td headers="sc">{@link DateFormat#getTimeInstance(int,Locale) DateFormat.getTimeInstance}{@code (}{@link DateFormat#DEFAULT}{@code , getLocale())}
* <tr>
* <td headers="fs"><code>short</code>
* <td headers="sc">{@link DateFormat#getTimeInstance(int,Locale) DateFormat.getTimeInstance}{@code (}{@link DateFormat#SHORT}{@code , getLocale())}
* <tr>
* <td headers="fs"><code>medium</code>
* <td headers="sc">{@link DateFormat#getTimeInstance(int,Locale) DateFormat.getTimeInstance}{@code (}{@link DateFormat#DEFAULT}{@code , getLocale())}
* <tr>
* <td headers="fs"><code>long</code>
* <td headers="sc">{@link DateFormat#getTimeInstance(int,Locale) DateFormat.getTimeInstance}{@code (}{@link DateFormat#LONG}{@code , getLocale())}
* <tr>
* <td headers="fs"><code>full</code>
* <td headers="sc">{@link DateFormat#getTimeInstance(int,Locale) DateFormat.getTimeInstance}{@code (}{@link DateFormat#FULL}{@code , getLocale())}
* <tr>
* <td headers="fs"><i>SubformatPattern</i>
* <td headers="sc">{@code new} {@link SimpleDateFormat#SimpleDateFormat(String,Locale) SimpleDateFormat}{@code (subformatPattern, getLocale())}
* <tr>
* <td headers="ft"><code>choice</code>
* <td headers="fs"><i>SubformatPattern</i>
* <td headers="sc">{@code new} {@link ChoiceFormat#ChoiceFormat(String) ChoiceFormat}{@code (subformatPattern)}
* </table>
*
* <h4>Usage Information</h4>
*
* <p>
* 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.
* <p>
* The first example uses the static method <code>MessageFormat.format</code>,
* which internally creates a <code>MessageFormat</code> for one-time use:
* <blockquote><pre>
* 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);
* </pre></blockquote>
* The output is:
* <blockquote><pre>
* At 12:30 PM on Jul 3, 2053, there was a disturbance in the Force on planet 7.
* </pre></blockquote>
*
* <p>
* The following example creates a <code>MessageFormat</code> instance that
* can be used repeatedly:
* <blockquote><pre>
* 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));
* </pre></blockquote>
* The output with different values for <code>fileCount</code>:
* <blockquote><pre>
* The disk "MyDisk" contains 0 file(s).
* The disk "MyDisk" contains 1 file(s).
* The disk "MyDisk" contains 1,273 file(s).
* </pre></blockquote>
*
* <p>
* For more sophisticated patterns, you can use a <code>ChoiceFormat</code>
* to produce correct forms for singular and plural:
* <blockquote><pre>
* 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));
* </pre></blockquote>
* The output with different values for <code>fileCount</code>:
* <blockquote><pre>
* The disk "MyDisk" contains no files.
* The disk "MyDisk" contains one file.
* The disk "MyDisk" contains 1,273 files.
* </pre></blockquote>
*
* <p>
* You can create the <code>ChoiceFormat</code> programmatically, as in the
* above example, or by using a pattern. See {@link ChoiceFormat}
* for more information.
* <blockquote><pre>{@code
* form.applyPattern(
* "There {0,choice,0#are no files|1#is one file|1<are {0,number,integer} files}.");
* }</pre></blockquote>
*
* <p>
* <strong>Note:</strong> As we see above, the string produced
* by a <code>ChoiceFormat</code> in <code>MessageFormat</code> is treated as special;
* occurrences of '{' are used to indicate subformats, and cause recursion.
* If you create both a <code>MessageFormat</code> and <code>ChoiceFormat</code>
* 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.
* <p>
* 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,
* <blockquote><pre>
* 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)}
* </pre></blockquote>
*
* <p>
* Likewise, parsing with a {@code MessageFormat} object using patterns containing
* multiple occurrences of the same argument would return the last match. For
* example,
* <blockquote><pre>
* 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")}
* </pre></blockquote>
*
* <h4><a name="synchronization">Synchronization</a></h4>
*
* <p>
* 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
*/
public class MessageFormat extends Format {
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
* <a href="#patterns">class description</a>.
*
* @param pattern the pattern for this message format
* @exception IllegalArgumentException if the pattern is invalid
*/
public MessageFormat(String pattern) {
this.locale = Locale.getDefault(Locale.Category.FORMAT);
applyPattern(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
* <a href="#patterns">class description</a>.
*
* @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
*/
public MessageFormat(String pattern, Locale locale) {
this.locale = locale;
applyPattern(pattern);
}
/**
* Sets the locale to be used when creating or comparing subformats.
* This affects subsequent calls
* <ul>
* <li>to the {@link #applyPattern applyPattern}
* and {@link #toPattern toPattern} methods if format elements specify
* a format type and therefore have the subformats created in the
* <code>applyPattern</code> method, as well as
* <li>to the <code>format</code> and
* {@link #formatToCharacterIterator formatToCharacterIterator} methods
* if format elements do not specify a format type and therefore have
* the subformats created in the formatting methods.
* </ul>
* 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
* <a href="#patterns">class description</a>.
*
* @param pattern the pattern for this message format
* @exception IllegalArgumentException if the pattern is invalid
*/
@SuppressWarnings("fallthrough") // fallthrough in switch is expected, suppress it
public void applyPattern(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;
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.
*
* @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];
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) {
result.append(",number,").append(((DecimalFormat)fmt).toPattern());
} else if (fmt instanceof ChoiceFormat) {
result.append(",choice,").append(((ChoiceFormat)fmt).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) {
result.append(",date,").append(((SimpleDateFormat)fmt).toPattern());
} else {
// UNKNOWN
}
} else if (index != MODIFIER_DEFAULT) {
result.append(',').append(DATE_TIME_MODIFIER_KEYWORDS[index]);
}
} else {
//result.append(", unknown");
}
result.append('}');
}
copyAndFixQuotes(pattern, lastOffset, pattern.length(), result);
return result.toString();
}
/**
* Sets the formats to use for the values passed into
* <code>format</code> methods or returned from <code>parse</code>
* methods. The indices of elements in <code>newFormats</code>
* correspond to the argument indices used in the previously set
* pattern string.
* The order of formats in <code>newFormats</code> thus corresponds to
* the order of elements in the <code>arguments</code> array passed
* to the <code>format</code> methods or the result array returned
* by the <code>parse</code> methods.
* <p>
* 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</code> are replaced.
*
* @param newFormats the new formats to use
* @exception NullPointerException if <code>newFormats</code> 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</code> corresponds to
* the order of format elements in the pattern string.
* <p>
* 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</code>
* formats are replaced.
* <p>
* 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</code> array passed to
* the <code>format</code> methods or the result array returned by
* the <code>parse</code> methods.
*
* @param newFormats the new formats to use
* @exception NullPointerException if <code>newFormats</code> 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</code> array passed
* to the <code>format</code> methods or the result array returned
* by the <code>parse</code> methods.
* <p>
* 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.
* <p>
* 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 {@code formatElementIndex} is equal to or
* larger than the number of format elements in the pattern string
*/
public void setFormat(int formatElementIndex, Format newFormat) {
formats[formatElementIndex] = newFormat;
}
/**
* Gets the formats used for the values passed into
* <code>format</code> methods or returned from <code>parse</code>
* 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</code> array passed
* to the <code>format</code> methods or the result array returned
* by the <code>parse</code> methods.
* <p>
* 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.
* <p>
* 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</code> array passed to
* the <code>format</code> methods or the result array returned by
* the <code>parse</code> 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</code>'s
* pattern, with format elements replaced by the formatted objects, to the
* provided <code>StringBuffer</code>.
* <p>
* The text substituted for the individual format elements is derived from
* the current subformat of the format element and the
* <code>arguments</code> element at the format element's argument index
* as indicated by the first matching line of the following table. An
* argument is <i>unavailable</i> if <code>arguments</code> is
* <code>null</code> or has fewer than argumentIndex+1 elements.
*
* <table border=1 summary="Examples of subformat,argument,and formatted text">
* <tr>
* <th>Subformat
* <th>Argument
* <th>Formatted Text
* <tr>
* <td><i>any</i>
* <td><i>unavailable</i>
* <td><code>"{" + argumentIndex + "}"</code>
* <tr>
* <td><i>any</i>
* <td><code>null</code>
* <td><code>"null"</code>
* <tr>
* <td><code>instanceof ChoiceFormat</code>
* <td><i>any</i>
* <td><code>subformat.format(argument).indexOf('{') >= 0 ?<br>
* (new MessageFormat(subformat.format(argument), getLocale())).format(argument) :
* subformat.format(argument)</code>
* <tr>
* <td><code>!= null</code>
* <td><i>any</i>
* <td><code>subformat.format(argument)</code>
* <tr>
* <td><code>null</code>
* <td><code>instanceof Number</code>
* <td><code>NumberFormat.getInstance(getLocale()).format(argument)</code>
* <tr>
* <td><code>null</code>
* <td><code>instanceof Date</code>
* <td><code>DateFormat.getDateTimeInstance(DateFormat.SHORT, DateFormat.SHORT, getLocale()).format(argument)</code>
* <tr>
* <td><code>null</code>
* <td><code>instanceof String</code>
* <td><code>argument</code>
* <tr>
* <td><code>null</code>
* <td><i>any</i>
* <td><code>argument.toString()</code>
* </table>
* <p>
* If <code>pos</code> is non-null, and refers to
* <code>Field.ARGUMENT</code>, 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.
* @return the string buffer passed in as {@code result}, with formatted
* text appended
* @exception IllegalArgumentException if an argument in the
* <code>arguments</code> array is not of the type
* expected by the format element(s) that use it.
*/
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
* <blockquote>
* <code>(new {@link #MessageFormat(String) MessageFormat}(pattern)).{@link #format(java.lang.Object[], java.lang.StringBuffer, java.text.FieldPosition) format}(arguments, new StringBuffer(), null).toString()</code>
* </blockquote>
*
* @param pattern the pattern string
* @param arguments object(s) to format
* @return the formatted string
* @exception IllegalArgumentException if the pattern is invalid,
* or if an argument in the <code>arguments</code> array
* is not of the type expected by the format element(s)
* that use it.
*/
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</code>'s
* pattern, with format elements replaced by the formatted objects, to the
* provided <code>StringBuffer</code>.
* This is equivalent to
* <blockquote>
* <code>{@link #format(java.lang.Object[], java.lang.StringBuffer, java.text.FieldPosition) format}((Object[]) arguments, result, pos)</code>
* </blockquote>
*
* @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
* <code>arguments</code> array is not of the type
* expected by the format element(s) that use it.
*/
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</code>'s pattern, producing an
* <code>AttributedCharacterIterator</code>.
* You can use the returned <code>AttributedCharacterIterator</code>
* to build the resulting String, as well as to determine information
* about the resulting String.
* <p>
* The text of the returned <code>AttributedCharacterIterator</code> is
* the same that would be returned by
* <blockquote>
* <code>{@link #format(java.lang.Object[], java.lang.StringBuffer, java.text.FieldPosition) format}(arguments, new StringBuffer(), null).toString()</code>
* </blockquote>
* <p>
* In addition, the <code>AttributedCharacterIterator</code> contains at
* least attributes indicating where text was generated from an
* argument in the <code>arguments</code> array. The keys of these attributes are of
* type <code>MessageFormat.Field</code>, their values are
* <code>Integer</code> objects indicating the index in the <code>arguments</code>
* array of the argument from which the text was generated.
* <p>
* The attributes/value from the underlying <code>Format</code>
* instances that <code>MessageFormat</code> uses will also be
* placed in the resulting <code>AttributedCharacterIterator</code>.
* 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 <code>arguments</code> is null.
* @exception IllegalArgumentException if an argument in the
* <code>arguments</code> array is not of the type
* expected by the format element(s) that use it.
* @since 1.4
*/
public AttributedCharacterIterator formatToCharacterIterator(Object arguments) {
StringBuffer result = new StringBuffer();
ArrayList<AttributedCharacterIterator> 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(
iterators.toArray(
new AttributedCharacterIterator[iterators.size()]));
}
/**
* Parses the string.
*
* <p>Caveats: The parse may fail in a number of circumstances.
* For example:
* <ul>
* <li>If one of the arguments does not occur in the pattern.
* <li>If the format of an argument loses information, such as
* with a choice format where a large number formats to "many".
* <li>Does not yet handle recursion (where
* the substituted strings contain {n} references.)
* <li>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"}.
* <li>If a single argument is parsed more than once in the string,
* then the later parse wins.
* </ul>
* 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
*/
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.
* <p>
* See the {@link #parse(String, ParsePosition)} method for more information
* on message parsing.
*
* @param source A <code>String</code> whose beginning should be parsed.
* @return An <code>Object</code> array parsed from the string.
* @exception 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.
* <p>
* The method attempts to parse text starting at the index given by
* <code>pos</code>.
* If parsing succeeds, then the index of <code>pos</code> 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</code> 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</code> is not
* changed, the error index of <code>pos</code> is set to the index of
* the character where the error occurred, and null is returned.
* <p>
* See the {@link #parse(String, ParsePosition)} method for more information
* on message parsing.
*
* @param source A <code>String</code>, part of which should be parsed.
* @param pos A <code>ParsePosition</code> object with index and error
* index information as described above.
* @return An <code>Object</code> array parsed from the string. In case of
* error, returns null.
* @exception NullPointerException if <code>pos</code> 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;
}
/**
* Equality comparison between two message format objects
*/
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)
&& ((locale != null && locale.equals(other.locale))
|| (locale == null && other.locale == null))
&& Arrays.equals(offsets,other.offsets)
&& Arrays.equals(argumentNumbers,other.argumentNumbers)
&& Arrays.equals(formats,other.formats));
}
/**
* Generates a hash code for the message format object.
*/
public int hashCode() {
return pattern.hashCode(); // enough for reasonable distribution
}
/**
* Defines constants that are used as attribute keys in the
* <code>AttributedCharacterIterator</code> returned
* from <code>MessageFormat.formatToCharacterIterator</code>.
*
* @since 1.4
*/
public static class Field extends Format.Field {
// Proclaim serial compatibility with 1.4 FCS
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
*/
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</code>.
* The value associated with the key will be an <code>Integer</code>
* indicating the index in the <code>arguments</code> array of the
* argument from which the text was generated.
*/
public final static 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</code>. Can also be thought of
* as the index of the highest-numbered element in <code>offsets</code> that is being used.
* All of these arrays should have the same number of elements being used as <code>offsets</code>
* 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</code> is
* non-null, AttributedCharacterIterator will be created from the
* subformats as necessary. If <code>characterIterators</code> is null
* and <code>fp</code> is non-null and identifies
* <code>Field.MESSAGE_ARGUMENT</code>, the location of
* the first replaced argument will be set in it.
*
* @exception IllegalArgumentException if an argument in the
* <code>arguments</code> array is not of the type
* expected by the format element(s) that use it.
*/
private StringBuffer subformat(Object[] arguments, StringBuffer result,
FieldPosition fp, List<AttributedCharacterIterator> characterIterators) {
// 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('{').append(argumentNumber).append('}');
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,
Integer.valueOf(argumentNumber)));
last = result.length();
}
arg = null;
}
if (arg != null && arg.length() > 0) {
result.append(arg);
characterIterators.add(
createAttributedCharacterIterator(
arg, Field.ARGUMENT,
Integer.valueOf(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;
}
/**
* Convenience method to append all the characters in
* <code>iterator</code> to the StringBuffer <code>result</code>.
*/
private void append(StringBuffer result, CharacterIterator iterator) {
if (iterator.first() != CharacterIterator.DONE) {
char aChar;
result.append(iterator.first());
while ((aChar = iterator.next()) != CharacterIterator.DONE) {
result.append(aChar);
}
}
}
// Indices for segments
private static final int SEG_RAW = 0;
private static final int SEG_INDEX = 1;
private static final int SEG_TYPE = 2;
private static final int SEG_MODIFIER = 3; // modifier or subformat
// Indices for type keywords
private static final int TYPE_NULL = 0;
private static final int TYPE_NUMBER = 1;
private static final int TYPE_DATE = 2;
private static final int TYPE_TIME = 3;
private static final int TYPE_CHOICE = 4;
private static final String[] TYPE_KEYWORDS = {
"",
"number",
"date",
"time",
"choice"
};
// Indices for number modifiers
private static final int MODIFIER_DEFAULT = 0; // common in number and date-time
private static final int MODIFIER_CURRENCY = 1;
private static final int MODIFIER_PERCENT = 2;
private static final int MODIFIER_INTEGER = 3;
private static final String[] NUMBER_MODIFIER_KEYWORDS = {
"",
"currency",
"percent",
"integer"
};
// Indices for date-time modifiers
private static final int MODIFIER_SHORT = 1;
private static final int MODIFIER_MEDIUM = 2;
private static final int MODIFIER_LONG = 3;
private static final int MODIFIER_FULL = 4;
private static final String[] DATE_TIME_MODIFIER_KEYWORDS = {
"",
"short",
"medium",
"long",
"full"
};
// Date-time style values corresponding to the date-time modifiers.
private static final int[] DATE_TIME_MODIFIERS = {
DateFormat.DEFAULT,
DateFormat.SHORT,
DateFormat.MEDIUM,
DateFormat.LONG,
DateFormat.FULL,
};
private void makeFormat(int position, int offsetNumber,
StringBuilder[] textSegments)
{
String[] segments = new String[textSegments.length];
for (int i = 0; i < textSegments.length; i++) {
StringBuilder oneseg = textSegments[i];
segments[i] = (oneseg != null) ? oneseg.toString() : "";
}
// get the argument number
int argumentNumber;
try {
argumentNumber = Integer.parseInt(segments[SEG_INDEX]); // always unlocalized!
} catch (NumberFormatException e) {
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