/* * Copyright (c) 2003, 2011, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package java.util; import java.io.BufferedWriter; import java.io.Closeable; import java.io.IOException; import java.io.File; import java.io.FileOutputStream; import java.io.FileNotFoundException; import java.io.Flushable; import java.io.OutputStream; import java.io.OutputStreamWriter; import java.io.PrintStream; import java.io.UnsupportedEncodingException; import java.math.BigDecimal; import java.math.BigInteger; import java.math.MathContext; import java.math.RoundingMode; import java.nio.charset.Charset; import java.nio.charset.IllegalCharsetNameException; import java.nio.charset.UnsupportedCharsetException; import java.text.DateFormatSymbols; import java.text.DecimalFormat; import java.text.DecimalFormatSymbols; import java.text.NumberFormat; import java.util.regex.Matcher; import java.util.regex.Pattern; import sun.misc.FpUtils; import sun.misc.DoubleConsts; import sun.misc.FormattedFloatingDecimal; /** * An interpreter for printf-style format strings. This class provides support * for layout justification and alignment, common formats for numeric, string, * and date/time data, and locale-specific output. Common Java types such as * {@code byte}, {@link java.math.BigDecimal BigDecimal}, and {@link Calendar} * are supported. Limited formatting customization for arbitrary user types is * provided through the {@link Formattable} interface. * *
Formatters are not necessarily safe for multithreaded access. Thread * safety is optional and is the responsibility of users of methods in this * class. * *
Formatted printing for the Java language is heavily inspired by C's * {@code printf}. Although the format strings are similar to C, some * customizations have been made to accommodate the Java language and exploit * some of its features. Also, Java formatting is more strict than C's; for * example, if a conversion is incompatible with a flag, an exception will be * thrown. In C inapplicable flags are silently ignored. The format strings * are thus intended to be recognizable to C programmers but not necessarily * completely compatible with those in C. * *
Examples of expected usage: * *
* ** StringBuilder sb = new StringBuilder(); * // Send all output to the Appendable object sb * Formatter formatter = new Formatter(sb, Locale.US); * * // Explicit argument indices may be used to re-order output. * formatter.format("%4$2s %3$2s %2$2s %1$2s", "a", "b", "c", "d") * // -> " d c b a" * * // Optional locale as the first argument can be used to get * // locale-specific formatting of numbers. The precision and width can be * // given to round and align the value. * formatter.format(Locale.FRANCE, "e = %+10.4f", Math.E); * // -> "e = +2,7183" * * // The '(' numeric flag may be used to format negative numbers with * // parentheses rather than a minus sign. Group separators are * // automatically inserted. * formatter.format("Amount gained or lost since last statement: $ %(,.2f", * balanceDelta); * // -> "Amount gained or lost since last statement: $ (6,217.58)" *
Convenience methods for common formatting requests exist as illustrated * by the following invocations: * *
* ** // Writes a formatted string to System.out. * System.out.format("Local time: %tT", Calendar.getInstance()); * // -> "Local time: 13:34:18" * * // Writes formatted output to System.err. * System.err.printf("Unable to open file '%1$s': %2$s", * fileName, exception.getMessage()); * // -> "Unable to open file 'food': No such file or directory" *
Like C's {@code sprintf(3)}, Strings may be formatted using the static * method {@link String#format(String,Object...) String.format}: * *
* ** // Format a string containing a date. * import java.util.Calendar; * import java.util.GregorianCalendar; * import static java.util.Calendar.*; * * Calendar c = new GregorianCalendar(1995, MAY, 23); * String s = String.format("Duke's Birthday: %1$tm %1$te,%1$tY", c); * // -> s == "Duke's Birthday: May 23, 1995" *
This specification is divided into two sections. The first section, Summary, covers the basic formatting concepts. This * section is intended for users who want to get started quickly and are * familiar with formatted printing in other programming languages. The second * section, Details, covers the specific implementation * details. It is intended for users who want more precise specification of * formatting behavior. * *
This section is intended to provide a brief overview of formatting * concepts. For precise behavioral details, refer to the Details section. * *
Every method which produces formatted output requires a format * string and an argument list. The format string is a {@link * String} which may contain fixed text and one or more embedded format * specifiers. Consider the following example: * *
* * This format string is the first argument to the {@code format} method. It * contains three format specifiers "{@code %1$tm}", "{@code %1$te}", and * "{@code %1$tY}" which indicate how the arguments should be processed and * where they should be inserted in the text. The remaining portions of the * format string are fixed text including {@code "Dukes Birthday: "} and any * other spaces or punctuation. * * The argument list consists of all arguments passed to the method after the * format string. In the above example, the argument list is of size one and * consists of the {@link java.util.Calendar Calendar} object {@code c}. * ** Calendar c = ...; * String s = String.format("Duke's Birthday: %1$tm %1$te,%1$tY", c); *
* ** %[argument_index$][flags][width][.precision]conversion *
The optional argument_index is a decimal integer indicating the * position of the argument in the argument list. The first argument is * referenced by "{@code 1$}", the second by "{@code 2$}", etc. * *
The optional flags is a set of characters that modify the output * format. The set of valid flags depends on the conversion. * *
The optional width is a non-negative decimal integer indicating * the minimum number of characters to be written to the output. * *
The optional precision is a non-negative decimal integer usually * used to restrict the number of characters. The specific behavior depends on * the conversion. * *
The required conversion is a character indicating how the * argument should be formatted. The set of valid conversions for a given * argument depends on the argument's data type. * *
* ** %[argument_index$][flags][width]conversion *
The optional argument_index, flags and width are * defined as above. * *
The required conversion is a two character sequence. The first * character is {@code 't'} or {@code 'T'}. The second character indicates * the format to be used. These characters are similar to but not completely * identical to those defined by GNU {@code date} and POSIX * {@code strftime(3c)}. * *
* ** %[flags][width]conversion *
The optional flags and width is defined as above. * *
The required conversion is a character indicating content to be * inserted in the output. * *
Conversions are divided into the following categories: * *
The following table summarizes the supported conversions. Conversions * denoted by an upper-case character (i.e. {@code 'B'}, {@code 'H'}, * {@code 'S'}, {@code 'C'}, {@code 'X'}, {@code 'E'}, {@code 'G'}, * {@code 'A'}, and {@code 'T'}) are the same as those for the corresponding * lower-case conversion characters except that the result is converted to * upper case according to the rules of the prevailing {@link java.util.Locale * Locale}. The result is equivalent to the following invocation of {@link * String#toUpperCase()} * *
* out.toUpperCase()* *
Conversion * | Argument Category * | Description * * |
---|---|---|
{@code 'b'}, {@code 'B'} * | general * | If the argument arg is {@code null}, then the result is * "{@code false}". If arg is a {@code boolean} or {@link * Boolean}, then the result is the string returned by {@link * String#valueOf(boolean) String.valueOf(arg)}. Otherwise, the result is * "true". * * |
{@code 'h'}, {@code 'H'} * | general * | If the argument arg is {@code null}, then the result is * "{@code null}". Otherwise, the result is obtained by invoking * {@code Integer.toHexString(arg.hashCode())}. * * |
{@code 's'}, {@code 'S'} * | general * | If the argument arg is {@code null}, then the result is * "{@code null}". If arg implements {@link Formattable}, then * {@link Formattable#formatTo arg.formatTo} is invoked. Otherwise, the * result is obtained by invoking {@code arg.toString()}. * * |
{@code 'c'}, {@code 'C'} * | character * | The result is a Unicode character * * |
{@code 'd'} * | integral * | The result is formatted as a decimal integer * * |
{@code 'o'} * | integral * | The result is formatted as an octal integer * * |
{@code 'x'}, {@code 'X'} * | integral * | The result is formatted as a hexadecimal integer * * |
{@code 'e'}, {@code 'E'} * | floating point * | The result is formatted as a decimal number in computerized * scientific notation * * |
{@code 'f'} * | floating point * | The result is formatted as a decimal number * * |
{@code 'g'}, {@code 'G'} * | floating point * | The result is formatted using computerized scientific notation or * decimal format, depending on the precision and the value after rounding. * * |
{@code 'a'}, {@code 'A'} * | floating point * | The result is formatted as a hexadecimal floating-point number with * a significand and an exponent * * |
{@code 't'}, {@code 'T'} * | date/time * | Prefix for date and time conversion characters. See Date/Time Conversions. * * |
{@code '%'} * | percent * | The result is a literal {@code '%'} ('\u0025') * * |
{@code 'n'} * | line separator * | The result is the platform-specific line separator * * |
Any characters not explicitly defined as conversions are illegal and are * reserved for future extensions. * *
The following date and time conversion suffix characters are defined for * the {@code 't'} and {@code 'T'} conversions. The types are similar to but * not completely identical to those defined by GNU {@code date} and POSIX * {@code strftime(3c)}. Additional conversion types are provided to access * Java-specific functionality (e.g. {@code 'L'} for milliseconds within the * second). * *
The following conversion characters are used for formatting times: * *
{@code 'H'} * | Hour of the day for the 24-hour clock, formatted as two digits with * a leading zero as necessary i.e. {@code 00 - 23}. * * |
{@code 'I'} * | Hour for the 12-hour clock, formatted as two digits with a leading * zero as necessary, i.e. {@code 01 - 12}. * * |
{@code 'k'} * | Hour of the day for the 24-hour clock, i.e. {@code 0 - 23}. * * |
{@code 'l'} * | Hour for the 12-hour clock, i.e. {@code 1 - 12}. * * |
{@code 'M'} * | Minute within the hour formatted as two digits with a leading zero * as necessary, i.e. {@code 00 - 59}. * * |
{@code 'S'} * | Seconds within the minute, formatted as two digits with a leading * zero as necessary, i.e. {@code 00 - 60} ("{@code 60}" is a special * value required to support leap seconds). * * |
{@code 'L'} * | Millisecond within the second formatted as three digits with * leading zeros as necessary, i.e. {@code 000 - 999}. * * |
{@code 'N'} * | Nanosecond within the second, formatted as nine digits with leading * zeros as necessary, i.e. {@code 000000000 - 999999999}. * * |
{@code 'p'} * | Locale-specific {@linkplain * java.text.DateFormatSymbols#getAmPmStrings morning or afternoon} marker * in lower case, e.g."{@code am}" or "{@code pm}". Use of the conversion * prefix {@code 'T'} forces this output to upper case. * * |
{@code 'z'} * | RFC 822 * style numeric time zone offset from GMT, e.g. {@code -0800}. This * value will be adjusted as necessary for Daylight Saving Time. For * {@code long}, {@link Long}, and {@link Date} the time zone used is * the {@linkplain TimeZone#getDefault() default time zone} for this * instance of the Java virtual machine. * * |
{@code 'Z'} * | A string representing the abbreviation for the time zone. This * value will be adjusted as necessary for Daylight Saving Time. For * {@code long}, {@link Long}, and {@link Date} the time zone used is * the {@linkplain TimeZone#getDefault() default time zone} for this * instance of the Java virtual machine. The Formatter's locale will * supersede the locale of the argument (if any). * * |
{@code 's'} * | Seconds since the beginning of the epoch starting at 1 January 1970 * {@code 00:00:00} UTC, i.e. {@code Long.MIN_VALUE/1000} to * {@code Long.MAX_VALUE/1000}. * * |
{@code 'Q'} * | Milliseconds since the beginning of the epoch starting at 1 January * 1970 {@code 00:00:00} UTC, i.e. {@code Long.MIN_VALUE} to * {@code Long.MAX_VALUE}. * * |
The following conversion characters are used for formatting dates: * *
{@code 'B'} * | Locale-specific {@linkplain java.text.DateFormatSymbols#getMonths * full month name}, e.g. {@code "January"}, {@code "February"}. * * |
{@code 'b'} * | Locale-specific {@linkplain * java.text.DateFormatSymbols#getShortMonths abbreviated month name}, * e.g. {@code "Jan"}, {@code "Feb"}. * * |
{@code 'h'} * | Same as {@code 'b'}. * * |
{@code 'A'} * | Locale-specific full name of the {@linkplain * java.text.DateFormatSymbols#getWeekdays day of the week}, * e.g. {@code "Sunday"}, {@code "Monday"} * * |
{@code 'a'} * | Locale-specific short name of the {@linkplain * java.text.DateFormatSymbols#getShortWeekdays day of the week}, * e.g. {@code "Sun"}, {@code "Mon"} * * |
{@code 'C'} * | Four-digit year divided by {@code 100}, formatted as two digits * with leading zero as necessary, i.e. {@code 00 - 99} * * |
{@code 'Y'} * | Year, formatted as at least four digits with leading zeros as * necessary, e.g. {@code 0092} equals {@code 92} CE for the Gregorian * calendar. * * |
{@code 'y'} * | Last two digits of the year, formatted with leading zeros as * necessary, i.e. {@code 00 - 99}. * * |
{@code 'j'} * | Day of year, formatted as three digits with leading zeros as * necessary, e.g. {@code 001 - 366} for the Gregorian calendar. * * |
{@code 'm'} * | Month, formatted as two digits with leading zeros as necessary, * i.e. {@code 01 - 13}. * * |
{@code 'd'} * | Day of month, formatted as two digits with leading zeros as * necessary, i.e. {@code 01 - 31} * * |
{@code 'e'} * | Day of month, formatted as two digits, i.e. {@code 1 - 31}. * * |
The following conversion characters are used for formatting common * date/time compositions. * *
{@code 'R'} * | Time formatted for the 24-hour clock as {@code "%tH:%tM"} * * |
{@code 'T'} * | Time formatted for the 24-hour clock as {@code "%tH:%tM:%tS"}. * * |
{@code 'r'} * | Time formatted for the 12-hour clock as {@code "%tI:%tM:%tS %Tp"}. * The location of the morning or afternoon marker ({@code '%Tp'}) may be * locale-dependent. * * |
{@code 'D'} * | Date formatted as {@code "%tm/%td/%ty"}. * * |
{@code 'F'} * | ISO 8601 * complete date formatted as {@code "%tY-%tm-%td"}. * * |
{@code 'c'} * | Date and time formatted as {@code "%ta %tb %td %tT %tZ %tY"}, * e.g. {@code "Sun Jul 20 16:17:00 EDT 1969"}. * * |
Any characters not explicitly defined as date/time conversion suffixes * are illegal and are reserved for future extensions. * *
The following table summarizes the supported flags. y means the * flag is supported for the indicated argument types. * *
Flag | General * | Character | Integral * | Floating Point * | Date/Time * | Description * * |
---|---|---|---|---|---|---|
'-' | y * | y * | y * | y * | y * | The result will be left-justified. * * |
'#' | y1 * | - * | y3 * | y * | - * | The result should use a conversion-dependent alternate form * * |
'+' | - * | - * | y4 * | y * | - * | The result will always include a sign * * |
' ' | - * | - * | y4 * | y * | - * | The result will include a leading space for positive values * * |
'0' | - * | - * | y * | y * | - * | The result will be zero-padded * * |
',' | - * | - * | y2 * | y5 * | - * | The result will include locale-specific {@linkplain * java.text.DecimalFormatSymbols#getGroupingSeparator grouping separators} * * |
'(' | - * | - * | y4 * | y5 * | - * | The result will enclose negative numbers in parentheses * * |
1 Depends on the definition of {@link Formattable}. * *
2 For {@code 'd'} conversion only. * *
3 For {@code 'o'}, {@code 'x'}, and {@code 'X'} * conversions only. * *
4 For {@code 'd'}, {@code 'o'}, {@code 'x'}, and * {@code 'X'} conversions applied to {@link java.math.BigInteger BigInteger} * or {@code 'd'} applied to {@code byte}, {@link Byte}, {@code short}, {@link * Short}, {@code int} and {@link Integer}, {@code long}, and {@link Long}. * *
5 For {@code 'e'}, {@code 'E'}, {@code 'f'}, * {@code 'g'}, and {@code 'G'} conversions only. * *
Any characters not explicitly defined as flags are illegal and are * reserved for future extensions. * *
The width is the minimum number of characters to be written to the * output. For the line separator conversion, width is not applicable; if it * is provided, an exception will be thrown. * *
For general argument types, the precision is the maximum number of * characters to be written to the output. * *
For the floating-point conversions {@code 'e'}, {@code 'E'}, and * {@code 'f'} the precision is the number of digits after the decimal * separator. If the conversion is {@code 'g'} or {@code 'G'}, then the * precision is the total number of digits in the resulting magnitude after * rounding. If the conversion is {@code 'a'} or {@code 'A'}, then the * precision must not be specified. * *
For character, integral, and date/time argument types and the percent * and line separator conversions, the precision is not applicable; if a * precision is provided, an exception will be thrown. * *
The argument index is a decimal integer indicating the position of the * argument in the argument list. The first argument is referenced by * "{@code 1$}", the second by "{@code 2$}", etc. * *
Another way to reference arguments by position is to use the * {@code '<'} ('\u003c') flag, which causes the argument for * the previous format specifier to be re-used. For example, the following two * statements would produce identical strings: * *
* ** Calendar c = ...; * String s1 = String.format("Duke's Birthday: %1$tm %1$te,%1$tY", c); * * String s2 = String.format("Duke's Birthday: %1$tm %<te,%<tY", c); *
This section is intended to provide behavioral details for formatting, * including conditions and exceptions, supported data types, localization, and * interactions between flags, conversions, and data types. For an overview of * formatting concepts, refer to the Summary * *
Any characters not explicitly defined as conversions, date/time * conversion suffixes, or flags are illegal and are reserved for * future extensions. Use of such a character in a format string will * cause an {@link UnknownFormatConversionException} or {@link * UnknownFormatFlagsException} to be thrown. * *
If the format specifier contains a width or precision with an invalid * value or which is otherwise unsupported, then a {@link * IllegalFormatWidthException} or {@link IllegalFormatPrecisionException} * respectively will be thrown. * *
If a format specifier contains a conversion character that is not * applicable to the corresponding argument, then an {@link * IllegalFormatConversionException} will be thrown. * *
All specified exceptions may be thrown by any of the {@code format} * methods of {@code Formatter} as well as by any {@code format} convenience * methods such as {@link String#format(String,Object...) String.format} and * {@link java.io.PrintStream#printf(String,Object...) PrintStream.printf}. * *
Conversions denoted by an upper-case character (i.e. {@code 'B'}, * {@code 'H'}, {@code 'S'}, {@code 'C'}, {@code 'X'}, {@code 'E'}, * {@code 'G'}, {@code 'A'}, and {@code 'T'}) are the same as those for the * corresponding lower-case conversion characters except that the result is * converted to upper case according to the rules of the prevailing {@link * java.util.Locale Locale}. The result is equivalent to the following * invocation of {@link String#toUpperCase()} * *
* out.toUpperCase()* *
The following general conversions may be applied to any argument type: * *
{@code 'b'} * | '\u0062' * | Produces either "{@code true}" or "{@code false}" as returned by
* {@link Boolean#toString(boolean)}.
*
* If the argument is {@code null}, then the result is * "{@code false}". If the argument is a {@code boolean} or {@link * Boolean}, then the result is the string returned by {@link * String#valueOf(boolean) String.valueOf()}. Otherwise, the result is * "{@code true}". * * If the {@code '#'} flag is given, then a {@link * FormatFlagsConversionMismatchException} will be thrown. * * |
{@code 'B'} * | '\u0042' * | The upper-case variant of {@code 'b'}. * * |
{@code 'h'} * | '\u0068' * | Produces a string representing the hash code value of the object.
*
* If the argument, arg is {@code null}, then the * result is "{@code null}". Otherwise, the result is obtained * by invoking {@code Integer.toHexString(arg.hashCode())}. * * If the {@code '#'} flag is given, then a {@link * FormatFlagsConversionMismatchException} will be thrown. * * |
{@code 'H'} * | '\u0048' * | The upper-case variant of {@code 'h'}. * * |
{@code 's'} * | '\u0073' * | Produces a string.
*
* If the argument is {@code null}, then the result is * "{@code null}". If the argument implements {@link Formattable}, then * its {@link Formattable#formatTo formatTo} method is invoked. * Otherwise, the result is obtained by invoking the argument's * {@code toString()} method. * * If the {@code '#'} flag is given and the argument is not a {@link * Formattable} , then a {@link FormatFlagsConversionMismatchException} * will be thrown. * * |
{@code 'S'} * | '\u0053' * | The upper-case variant of {@code 's'}. * * |
The following flags apply to general conversions: * *
{@code '-'} * | '\u002d' * | Left justifies the output. Spaces ('\u0020') will be * added at the end of the converted value as required to fill the minimum * width of the field. If the width is not provided, then a {@link * MissingFormatWidthException} will be thrown. If this flag is not given * then the output will be right-justified. * * |
{@code '#'} * | '\u0023' * | Requires the output use an alternate form. The definition of the * form is specified by the conversion. * * |
The width is the minimum number of characters to * be written to the * output. If the length of the converted value is less than the width then * the output will be padded by ' ' ('\u0020') * until the total number of characters equals the width. The padding is on * the left by default. If the {@code '-'} flag is given, then the padding * will be on the right. If the width is not specified then there is no * minimum. * *
The precision is the maximum number of characters to be written to the * output. The precision is applied before the width, thus the output will be * truncated to {@code precision} characters even if the width is greater than * the precision. If the precision is not specified then there is no explicit * limit on the number of characters. * *
{@code 'c'} * | '\u0063' * | Formats the argument as a Unicode character as described in Unicode Character
* Representation. This may be more than one 16-bit {@code char} in
* the case where the argument represents a supplementary character.
*
* If the {@code '#'} flag is given, then a {@link * FormatFlagsConversionMismatchException} will be thrown. * * |
{@code 'C'} * | '\u0043' * | The upper-case variant of {@code 'c'}. * * |
The {@code '-'} flag defined for General * conversions applies. If the {@code '#'} flag is given, then a {@link * FormatFlagsConversionMismatchException} will be thrown. * *
The width is defined as for General conversions. * *
The precision is not applicable. If the precision is specified then an * {@link IllegalFormatPrecisionException} will be thrown. * *
Numeric conversions are divided into the following categories: * *
Numeric types will be formatted according to the following algorithm: * *
Number Localization Algorithm * *
After digits are obtained for the integer part, fractional part, and * exponent (as appropriate for the data type), the following transformation * is applied: * *
If the value is NaN or positive infinity the literal strings "NaN" or * "Infinity" respectively, will be output. If the value is negative infinity, * then the output will be "(Infinity)" if the {@code '('} flag is given * otherwise the output will be "-Infinity". These values are not localized. * *
Byte, Short, Integer, and Long * *
The following conversions may be applied to {@code byte}, {@link Byte}, * {@code short}, {@link Short}, {@code int} and {@link Integer}, * {@code long}, and {@link Long}. * *
{@code 'd'} * | '\u0054' * | Formats the argument as a decimal integer. The localization algorithm is applied.
*
* If the {@code '0'} flag is given and the value is negative, then * the zero padding will occur after the sign. * * If the {@code '#'} flag is given then a {@link * FormatFlagsConversionMismatchException} will be thrown. * * |
{@code 'o'} * | '\u006f' * | Formats the argument as an integer in base eight. No localization
* is applied.
*
* If x is negative then the result will be an unsigned value * generated by adding 2n to the value where {@code n} is the * number of bits in the type as returned by the static {@code SIZE} field * in the {@linkplain Byte#SIZE Byte}, {@linkplain Short#SIZE Short}, * {@linkplain Integer#SIZE Integer}, or {@linkplain Long#SIZE Long} * classes as appropriate. * * If the {@code '#'} flag is given then the output will always begin * with the radix indicator {@code '0'}. * * If the {@code '0'} flag is given then the output will be padded * with leading zeros to the field width following any indication of sign. * * If {@code '('}, {@code '+'}, '  ', or {@code ','} flags * are given then a {@link FormatFlagsConversionMismatchException} will be * thrown. * * |
{@code 'x'} * | '\u0078' * | Formats the argument as an integer in base sixteen. No
* localization is applied.
*
* If x is negative then the result will be an unsigned value * generated by adding 2n to the value where {@code n} is the * number of bits in the type as returned by the static {@code SIZE} field * in the {@linkplain Byte#SIZE Byte}, {@linkplain Short#SIZE Short}, * {@linkplain Integer#SIZE Integer}, or {@linkplain Long#SIZE Long} * classes as appropriate. * * If the {@code '#'} flag is given then the output will always begin * with the radix indicator {@code "0x"}. * * If the {@code '0'} flag is given then the output will be padded to * the field width with leading zeros after the radix indicator or sign (if * present). * * If {@code '('}, ' ', {@code '+'}, or * {@code ','} flags are given then a {@link * FormatFlagsConversionMismatchException} will be thrown. * * |
{@code 'X'} * | '\u0058' * | The upper-case variant of {@code 'x'}. The entire string * representing the number will be converted to {@linkplain * String#toUpperCase upper case} including the {@code 'x'} (if any) and * all hexadecimal digits {@code 'a'} - {@code 'f'} * ('\u0061' - '\u0066'). * * |
If the conversion is {@code 'o'}, {@code 'x'}, or {@code 'X'} and * both the {@code '#'} and the {@code '0'} flags are given, then result will * contain the radix indicator ({@code '0'} for octal and {@code "0x"} or * {@code "0X"} for hexadecimal), some number of zeros (based on the width), * and the value. * *
If the {@code '-'} flag is not given, then the space padding will occur * before the sign. * *
The following flags apply to numeric integral * conversions: * *
{@code '+'} * | '\u002b' * | Requires the output to include a positive sign for all positive
* numbers. If this flag is not given then only negative values will
* include a sign.
*
* If both the {@code '+'} and ' ' flags are given * then an {@link IllegalFormatFlagsException} will be thrown. * * |
' ' * | '\u0020' * | Requires the output to include a single extra space
* ('\u0020') for non-negative values.
*
* If both the {@code '+'} and ' ' flags are given * then an {@link IllegalFormatFlagsException} will be thrown. * * |
{@code '0'} * | '\u0030' * | Requires the output to be padded with leading {@linkplain
* java.text.DecimalFormatSymbols#getZeroDigit zeros} to the minimum field
* width following any sign or radix indicator except when converting NaN
* or infinity. If the width is not provided, then a {@link
* MissingFormatWidthException} will be thrown.
*
* If both the {@code '-'} and {@code '0'} flags are given then an * {@link IllegalFormatFlagsException} will be thrown. * * |
{@code ','} * | '\u002c' * | Requires the output to include the locale-specific {@linkplain * java.text.DecimalFormatSymbols#getGroupingSeparator group separators} as * described in the "group" section of the * localization algorithm. * * |
{@code '('} * | '\u0028' * | Requires the output to prepend a {@code '('} * ('\u0028') and append a {@code ')'} * ('\u0029') to negative values. * * |
If no flags are given the default formatting is * as follows: * *
The width is the minimum number of characters to * be written to the output. This includes any signs, digits, grouping * separators, radix indicator, and parentheses. If the length of the * converted value is less than the width then the output will be padded by * spaces ('\u0020') until the total number of characters equals * width. The padding is on the left by default. If {@code '-'} flag is * given then the padding will be on the right. If width is not specified then * there is no minimum. * *
The precision is not applicable. If precision is specified then an * {@link IllegalFormatPrecisionException} will be thrown. * *
BigInteger * *
The following conversions may be applied to {@link * java.math.BigInteger}. * *
{@code 'd'} * | '\u0054' * | Requires the output to be formatted as a decimal integer. The localization algorithm is applied.
*
* If the {@code '#'} flag is given {@link * FormatFlagsConversionMismatchException} will be thrown. * * |
{@code 'o'} * | '\u006f' * | Requires the output to be formatted as an integer in base eight.
* No localization is applied.
*
* If x is negative then the result will be a signed value * beginning with {@code '-'} ('\u002d'). Signed output is * allowed for this type because unlike the primitive types it is not * possible to create an unsigned equivalent without assuming an explicit * data-type size. * * If x is positive or zero and the {@code '+'} flag is given * then the result will begin with {@code '+'} ('\u002b'). * * If the {@code '#'} flag is given then the output will always begin * with {@code '0'} prefix. * * If the {@code '0'} flag is given then the output will be padded * with leading zeros to the field width following any indication of sign. * * If the {@code ','} flag is given then a {@link * FormatFlagsConversionMismatchException} will be thrown. * * |
{@code 'x'} * | '\u0078' * | Requires the output to be formatted as an integer in base
* sixteen. No localization is applied.
*
* If x is negative then the result will be a signed value * beginning with {@code '-'} ('\u002d'). Signed output is * allowed for this type because unlike the primitive types it is not * possible to create an unsigned equivalent without assuming an explicit * data-type size. * * If x is positive or zero and the {@code '+'} flag is given * then the result will begin with {@code '+'} ('\u002b'). * * If the {@code '#'} flag is given then the output will always begin * with the radix indicator {@code "0x"}. * * If the {@code '0'} flag is given then the output will be padded to * the field width with leading zeros after the radix indicator or sign (if * present). * * If the {@code ','} flag is given then a {@link * FormatFlagsConversionMismatchException} will be thrown. * * |
{@code 'X'} * | '\u0058' * | The upper-case variant of {@code 'x'}. The entire string * representing the number will be converted to {@linkplain * String#toUpperCase upper case} including the {@code 'x'} (if any) and * all hexadecimal digits {@code 'a'} - {@code 'f'} * ('\u0061' - '\u0066'). * * |
If the conversion is {@code 'o'}, {@code 'x'}, or {@code 'X'} and * both the {@code '#'} and the {@code '0'} flags are given, then result will * contain the base indicator ({@code '0'} for octal and {@code "0x"} or * {@code "0X"} for hexadecimal), some number of zeros (based on the width), * and the value. * *
If the {@code '0'} flag is given and the value is negative, then the * zero padding will occur after the sign. * *
If the {@code '-'} flag is not given, then the space padding will occur * before the sign. * *
All flags defined for Byte, Short, Integer, and * Long apply. The default behavior when no flags are * given is the same as for Byte, Short, Integer, and Long. * *
The specification of width is the same as * defined for Byte, Short, Integer, and Long. * *
The precision is not applicable. If precision is specified then an * {@link IllegalFormatPrecisionException} will be thrown. * *
Float and Double * *
The following conversions may be applied to {@code float}, {@link * Float}, {@code double} and {@link Double}. * *
{@code 'e'} * | '\u0065' * | Requires the output to be formatted using computerized scientific notation. The localization algorithm is applied.
*
* The formatting of the magnitude m depends upon its value. * * If m is NaN or infinite, the literal strings "NaN" or * "Infinity", respectively, will be output. These values are not * localized. * * If m is positive-zero or negative-zero, then the exponent * will be {@code "+00"}. * * Otherwise, the result is a string that represents the sign and * magnitude (absolute value) of the argument. The formatting of the sign * is described in the localization * algorithm. The formatting of the magnitude m depends upon its * value. * * Let n be the unique integer such that 10n * <= m < 10n+1; then let a be the * mathematically exact quotient of m and 10n so * that 1 <= a < 10. The magnitude is then represented as the * integer part of a, as a single decimal digit, followed by the * decimal separator followed by decimal digits representing the fractional * part of a, followed by the exponent symbol {@code 'e'} * ('\u0065'), followed by the sign of the exponent, followed * by a representation of n as a decimal integer, as produced by the * method {@link Long#toString(long, int)}, and zero-padded to include at * least two digits. * * The number of digits in the result for the fractional part of * m or a is equal to the precision. If the precision is not * specified then the default value is {@code 6}. If the precision is less * than the number of digits which would appear after the decimal point in * the string returned by {@link Float#toString(float)} or {@link * Double#toString(double)} respectively, then the value will be rounded * using the {@linkplain java.math.BigDecimal#ROUND_HALF_UP round half up * algorithm}. Otherwise, zeros may be appended to reach the precision. * For a canonical representation of the value, use {@link * Float#toString(float)} or {@link Double#toString(double)} as * appropriate. * * If the {@code ','} flag is given, then an {@link * FormatFlagsConversionMismatchException} will be thrown. * * |
{@code 'E'} * | '\u0045' * | The upper-case variant of {@code 'e'}. The exponent symbol * will be {@code 'E'} ('\u0045'). * * |
{@code 'g'} * | '\u0067' * | Requires the output to be formatted in general scientific notation
* as described below. The localization
* algorithm is applied.
*
* After rounding for the precision, the formatting of the resulting * magnitude m depends on its value. * * If m is greater than or equal to 10-4 but less * than 10precision then it is represented in decimal format. * * If m is less than 10-4 or greater than or equal to * 10precision, then it is represented in computerized scientific notation. * * The total number of significant digits in m is equal to the * precision. If the precision is not specified, then the default value is * {@code 6}. If the precision is {@code 0}, then it is taken to be * {@code 1}. * * If the {@code '#'} flag is given then an {@link * FormatFlagsConversionMismatchException} will be thrown. * * |
{@code 'G'} * | '\u0047' * | The upper-case variant of {@code 'g'}. * * |
{@code 'f'} * | '\u0066' * | Requires the output to be formatted using decimal
* format. The localization algorithm is
* applied.
*
* The result is a string that represents the sign and magnitude * (absolute value) of the argument. The formatting of the sign is * described in the localization * algorithm. The formatting of the magnitude m depends upon its * value. * * If m NaN or infinite, the literal strings "NaN" or * "Infinity", respectively, will be output. These values are not * localized. * * The magnitude is formatted as the integer part of m, with no * leading zeroes, followed by the decimal separator followed by one or * more decimal digits representing the fractional part of m. * * The number of digits in the result for the fractional part of * m or a is equal to the precision. If the precision is not * specified then the default value is {@code 6}. If the precision is less * than the number of digits which would appear after the decimal point in * the string returned by {@link Float#toString(float)} or {@link * Double#toString(double)} respectively, then the value will be rounded * using the {@linkplain java.math.BigDecimal#ROUND_HALF_UP round half up * algorithm}. Otherwise, zeros may be appended to reach the precision. * For a canonical representation of the value, use {@link * Float#toString(float)} or {@link Double#toString(double)} as * appropriate. * * |
{@code 'a'} * | '\u0061' * | Requires the output to be formatted in hexadecimal exponential
* form. No localization is applied.
*
* The result is a string that represents the sign and magnitude * (absolute value) of the argument x. * * If x is negative or a negative-zero value then the result * will begin with {@code '-'} ('\u002d'). * * If x is positive or a positive-zero value and the * {@code '+'} flag is given then the result will begin with {@code '+'} * ('\u002b'). * * The formatting of the magnitude m depends upon its value. * *
If the {@code '('} or {@code ','} flags are given, then a {@link * FormatFlagsConversionMismatchException} will be thrown. * * |
{@code 'A'} * | '\u0041' * | The upper-case variant of {@code 'a'}. The entire string * representing the number will be converted to upper case including the * {@code 'x'} ('\u0078') and {@code 'p'} * ('\u0070' and all hexadecimal digits {@code 'a'} - * {@code 'f'} ('\u0061' - '\u0066'). * * |
All flags defined for Byte, Short, Integer, and * Long apply. * *
If the {@code '#'} flag is given, then the decimal separator will * always be present. * *
If no flags are given the default formatting * is as follows: * *
The width is the minimum number of characters * to be written to the output. This includes any signs, digits, grouping * separators, decimal separators, exponential symbol, radix indicator, * parentheses, and strings representing infinity and NaN as applicable. If * the length of the converted value is less than the width then the output * will be padded by spaces ('\u0020') until the total number of * characters equals width. The padding is on the left by default. If the * {@code '-'} flag is given then the padding will be on the right. If width * is not specified then there is no minimum. * *
If the conversion is {@code 'e'}, * {@code 'E'} or {@code 'f'}, then the precision is the number of digits * after the decimal separator. If the precision is not specified, then it is * assumed to be {@code 6}. * *
If the conversion is {@code 'g'} or {@code 'G'}, then the precision is * the total number of significant digits in the resulting magnitude after * rounding. If the precision is not specified, then the default value is * {@code 6}. If the precision is {@code 0}, then it is taken to be * {@code 1}. * *
If the conversion is {@code 'a'} or {@code 'A'}, then the precision * is the number of hexadecimal digits after the decimal separator. If the * precision is not provided, then all of the digits as returned by {@link * Double#toHexString(double)} will be output. * *
BigDecimal * *
The following conversions may be applied {@link java.math.BigDecimal * BigDecimal}. * *
{@code 'e'} * | '\u0065' * | Requires the output to be formatted using computerized scientific notation. The localization algorithm is applied.
*
* The formatting of the magnitude m depends upon its value. * * If m is positive-zero or negative-zero, then the exponent * will be {@code "+00"}. * * Otherwise, the result is a string that represents the sign and * magnitude (absolute value) of the argument. The formatting of the sign * is described in the localization * algorithm. The formatting of the magnitude m depends upon its * value. * * Let n be the unique integer such that 10n * <= m < 10n+1; then let a be the * mathematically exact quotient of m and 10n so * that 1 <= a < 10. The magnitude is then represented as the * integer part of a, as a single decimal digit, followed by the * decimal separator followed by decimal digits representing the fractional * part of a, followed by the exponent symbol {@code 'e'} * ('\u0065'), followed by the sign of the exponent, followed * by a representation of n as a decimal integer, as produced by the * method {@link Long#toString(long, int)}, and zero-padded to include at * least two digits. * * The number of digits in the result for the fractional part of * m or a is equal to the precision. If the precision is not * specified then the default value is {@code 6}. If the precision is * less than the number of digits to the right of the decimal point then * the value will be rounded using the * {@linkplain java.math.BigDecimal#ROUND_HALF_UP round half up * algorithm}. Otherwise, zeros may be appended to reach the precision. * For a canonical representation of the value, use {@link * BigDecimal#toString()}. * * If the {@code ','} flag is given, then an {@link * FormatFlagsConversionMismatchException} will be thrown. * * |
{@code 'E'} * | '\u0045' * | The upper-case variant of {@code 'e'}. The exponent symbol * will be {@code 'E'} ('\u0045'). * * |
{@code 'g'} * | '\u0067' * | Requires the output to be formatted in general scientific notation
* as described below. The localization
* algorithm is applied.
*
* After rounding for the precision, the formatting of the resulting * magnitude m depends on its value. * * If m is greater than or equal to 10-4 but less * than 10precision then it is represented in decimal format. * * If m is less than 10-4 or greater than or equal to * 10precision, then it is represented in computerized scientific notation. * * The total number of significant digits in m is equal to the * precision. If the precision is not specified, then the default value is * {@code 6}. If the precision is {@code 0}, then it is taken to be * {@code 1}. * * If the {@code '#'} flag is given then an {@link * FormatFlagsConversionMismatchException} will be thrown. * * |
{@code 'G'} * | '\u0047' * | The upper-case variant of {@code 'g'}. * * |
{@code 'f'} * | '\u0066' * | Requires the output to be formatted using decimal
* format. The localization algorithm is
* applied.
*
* The result is a string that represents the sign and magnitude * (absolute value) of the argument. The formatting of the sign is * described in the localization * algorithm. The formatting of the magnitude m depends upon its * value. * * The magnitude is formatted as the integer part of m, with no * leading zeroes, followed by the decimal separator followed by one or * more decimal digits representing the fractional part of m. * * The number of digits in the result for the fractional part of * m or a is equal to the precision. If the precision is not * specified then the default value is {@code 6}. If the precision is * less than the number of digits to the right of the decimal point * then the value will be rounded using the * {@linkplain java.math.BigDecimal#ROUND_HALF_UP round half up * algorithm}. Otherwise, zeros may be appended to reach the precision. * For a canonical representation of the value, use {@link * BigDecimal#toString()}. * * |
All flags defined for Byte, Short, Integer, and * Long apply. * *
If the {@code '#'} flag is given, then the decimal separator will * always be present. * *
The default behavior when no flags are * given is the same as for Float and Double. * *
The specification of width and precision is the same as defined for Float and * Double. * *
This conversion may be applied to {@code long}, {@link Long}, {@link * Calendar}, and {@link Date}. * *
{@code 't'} * | '\u0074' * | Prefix for date and time conversion characters. * |
{@code 'T'} * | '\u0054' * | The upper-case variant of {@code 't'}. * * |
The following date and time conversion character suffixes are defined * for the {@code 't'} and {@code 'T'} conversions. The types are similar to * but not completely identical to those defined by GNU {@code date} and * POSIX {@code strftime(3c)}. Additional conversion types are provided to * access Java-specific functionality (e.g. {@code 'L'} for milliseconds * within the second). * *
The following conversion characters are used for formatting times: * *
{@code 'H'} * | '\u0048' * | Hour of the day for the 24-hour clock, formatted as two digits with * a leading zero as necessary i.e. {@code 00 - 23}. {@code 00} * corresponds to midnight. * * |
{@code 'I'} * | '\u0049' * | Hour for the 12-hour clock, formatted as two digits with a leading * zero as necessary, i.e. {@code 01 - 12}. {@code 01} corresponds to * one o'clock (either morning or afternoon). * * |
{@code 'k'} * | '\u006b' * | Hour of the day for the 24-hour clock, i.e. {@code 0 - 23}. * {@code 0} corresponds to midnight. * * |
{@code 'l'} * | '\u006c' * | Hour for the 12-hour clock, i.e. {@code 1 - 12}. {@code 1} * corresponds to one o'clock (either morning or afternoon). * * |
{@code 'M'} * | '\u004d' * | Minute within the hour formatted as two digits with a leading zero * as necessary, i.e. {@code 00 - 59}. * * |
{@code 'S'} * | '\u0053' * | Seconds within the minute, formatted as two digits with a leading * zero as necessary, i.e. {@code 00 - 60} ("{@code 60}" is a special * value required to support leap seconds). * * |
{@code 'L'} * | '\u004c' * | Millisecond within the second formatted as three digits with * leading zeros as necessary, i.e. {@code 000 - 999}. * * |
{@code 'N'} * | '\u004e' * | Nanosecond within the second, formatted as nine digits with leading * zeros as necessary, i.e. {@code 000000000 - 999999999}. The precision * of this value is limited by the resolution of the underlying operating * system or hardware. * * |
{@code 'p'} * | '\u0070' * | Locale-specific {@linkplain * java.text.DateFormatSymbols#getAmPmStrings morning or afternoon} marker * in lower case, e.g."{@code am}" or "{@code pm}". Use of the * conversion prefix {@code 'T'} forces this output to upper case. (Note * that {@code 'p'} produces lower-case output. This is different from * GNU {@code date} and POSIX {@code strftime(3c)} which produce * upper-case output.) * * |
{@code 'z'} * | '\u007a' * | RFC 822 * style numeric time zone offset from GMT, e.g. {@code -0800}. This * value will be adjusted as necessary for Daylight Saving Time. For * {@code long}, {@link Long}, and {@link Date} the time zone used is * the {@linkplain TimeZone#getDefault() default time zone} for this * instance of the Java virtual machine. * * |
{@code 'Z'} * | '\u005a' * | A string representing the abbreviation for the time zone. This * value will be adjusted as necessary for Daylight Saving Time. For * {@code long}, {@link Long}, and {@link Date} the time zone used is * the {@linkplain TimeZone#getDefault() default time zone} for this * instance of the Java virtual machine. The Formatter's locale will * supersede the locale of the argument (if any). * * |
{@code 's'} * | '\u0073' * | Seconds since the beginning of the epoch starting at 1 January 1970 * {@code 00:00:00} UTC, i.e. {@code Long.MIN_VALUE/1000} to * {@code Long.MAX_VALUE/1000}. * * |
{@code 'Q'} * | '\u004f' * | Milliseconds since the beginning of the epoch starting at 1 January * 1970 {@code 00:00:00} UTC, i.e. {@code Long.MIN_VALUE} to * {@code Long.MAX_VALUE}. The precision of this value is limited by * the resolution of the underlying operating system or hardware. * * |
The following conversion characters are used for formatting dates: * *
{@code 'B'} * | '\u0042' * | Locale-specific {@linkplain java.text.DateFormatSymbols#getMonths * full month name}, e.g. {@code "January"}, {@code "February"}. * * |
{@code 'b'} * | '\u0062' * | Locale-specific {@linkplain * java.text.DateFormatSymbols#getShortMonths abbreviated month name}, * e.g. {@code "Jan"}, {@code "Feb"}. * * |
{@code 'h'} * | '\u0068' * | Same as {@code 'b'}. * * |
{@code 'A'} * | '\u0041' * | Locale-specific full name of the {@linkplain * java.text.DateFormatSymbols#getWeekdays day of the week}, * e.g. {@code "Sunday"}, {@code "Monday"} * * |
{@code 'a'} * | '\u0061' * | Locale-specific short name of the {@linkplain * java.text.DateFormatSymbols#getShortWeekdays day of the week}, * e.g. {@code "Sun"}, {@code "Mon"} * * |
{@code 'C'} * | '\u0043' * | Four-digit year divided by {@code 100}, formatted as two digits * with leading zero as necessary, i.e. {@code 00 - 99} * * |
{@code 'Y'} * | '\u0059' | Year, formatted to at least * four digits with leading zeros as necessary, e.g. {@code 0092} equals * {@code 92} CE for the Gregorian calendar. * * |
{@code 'y'} * | '\u0079' * | Last two digits of the year, formatted with leading zeros as * necessary, i.e. {@code 00 - 99}. * * |
{@code 'j'} * | '\u006a' * | Day of year, formatted as three digits with leading zeros as * necessary, e.g. {@code 001 - 366} for the Gregorian calendar. * {@code 001} corresponds to the first day of the year. * * |
{@code 'm'} * | '\u006d' * | Month, formatted as two digits with leading zeros as necessary, * i.e. {@code 01 - 13}, where "{@code 01}" is the first month of the * year and ("{@code 13}" is a special value required to support lunar * calendars). * * |
{@code 'd'} * | '\u0064' * | Day of month, formatted as two digits with leading zeros as * necessary, i.e. {@code 01 - 31}, where "{@code 01}" is the first day * of the month. * * |
{@code 'e'} * | '\u0065' * | Day of month, formatted as two digits, i.e. {@code 1 - 31} where * "{@code 1}" is the first day of the month. * * |
The following conversion characters are used for formatting common * date/time compositions. * *
{@code 'R'} * | '\u0052' * | Time formatted for the 24-hour clock as {@code "%tH:%tM"} * * |
{@code 'T'} * | '\u0054' * | Time formatted for the 24-hour clock as {@code "%tH:%tM:%tS"}. * * |
{@code 'r'} * | '\u0072' * | Time formatted for the 12-hour clock as {@code "%tI:%tM:%tS * %Tp"}. The location of the morning or afternoon marker * ({@code '%Tp'}) may be locale-dependent. * * |
{@code 'D'} * | '\u0044' * | Date formatted as {@code "%tm/%td/%ty"}. * * |
{@code 'F'} * | '\u0046' * | ISO 8601 * complete date formatted as {@code "%tY-%tm-%td"}. * * |
{@code 'c'} * | '\u0063' * | Date and time formatted as {@code "%ta %tb %td %tT %tZ %tY"}, * e.g. {@code "Sun Jul 20 16:17:00 EDT 1969"}. * * |
The {@code '-'} flag defined for General * conversions applies. If the {@code '#'} flag is given, then a {@link * FormatFlagsConversionMismatchException} will be thrown. * *
The width is the minimum number of characters to * be written to the output. If the length of the converted value is less than * the {@code width} then the output will be padded by spaces * ('\u0020') until the total number of characters equals width. * The padding is on the left by default. If the {@code '-'} flag is given * then the padding will be on the right. If width is not specified then there * is no minimum. * *
The precision is not applicable. If the precision is specified then an * {@link IllegalFormatPrecisionException} will be thrown. * *
The conversion does not correspond to any argument. * *
{@code '%'} * | The result is a literal {@code '%'} ('\u0025')
*
* The width is the minimum number of characters to * be written to the output including the {@code '%'}. If the length of the * converted value is less than the {@code width} then the output will be * padded by spaces ('\u0020') until the total number of * characters equals width. The padding is on the left. If width is not * specified then just the {@code '%'} is output. * * The {@code '-'} flag defined for General * conversions applies. If any other flags are provided, then a * {@link FormatFlagsConversionMismatchException} will be thrown. * * The precision is not applicable. If the precision is specified an * {@link IllegalFormatPrecisionException} will be thrown. * * |
The conversion does not correspond to any argument. * *
{@code 'n'} * | the platform-specific line separator as returned by {@link * System#getProperty System.getProperty("line.separator")}. * * |
Flags, width, and precision are not applicable. If any are provided an * {@link IllegalFormatFlagsException}, {@link IllegalFormatWidthException}, * and {@link IllegalFormatPrecisionException}, respectively will be thrown. * *
Format specifiers can reference arguments in three ways: * *
For example: * *
* ** formatter.format("%4$s %3$s %2$s %1$s %4$s %3$s %2$s %1$s", * "a", "b", "c", "d") * // -> "d c b a d c b a" *
* ** formatter.format("%s %s %<s %<s", "a", "b", "c", "d") * // -> "a b b b" * // "c" and "d" are ignored because they are not referenced *
* ** formatter.format("%s %s %s %s", "a", "b", "c", "d") * // -> "a b c d" *
It is possible to have a format string which uses all forms of indexing, * for example: * *
* ** formatter.format("%2$s %s %<s %s", "a", "b", "c", "d") * // -> "b a a b" * // "c" and "d" are ignored because they are not referenced *
The maximum number of arguments is limited by the maximum dimension of a * Java array as defined by * The Java™ Virtual Machine Specification. * If the argument index is does not correspond to an * available argument, then a {@link MissingFormatArgumentException} is thrown. * *
If there are more arguments than format specifiers, the extra arguments * are ignored. * *
Unless otherwise specified, passing a {@code null} argument to any * method or constructor in this class will cause a {@link * NullPointerException} to be thrown. * * @author Iris Clark * @since 1.5 */ public final class Formatter implements Closeable, Flushable { private Appendable a; private final Locale l; private IOException lastException; private final char zero; private static double scaleUp; // 1 (sign) + 19 (max # sig digits) + 1 ('.') + 1 ('e') + 1 (sign) // + 3 (max # exp digits) + 4 (error) = 30 private static final int MAX_FD_CHARS = 30; /** * Returns a charset object for the given charset name. * @throws NullPointerException is csn is null * @throws UnsupportedEncodingException if the charset is not supported */ private static Charset toCharset(String csn) throws UnsupportedEncodingException { Objects.requireNonNull(csn, "charsetName"); try { return Charset.forName(csn); } catch (IllegalCharsetNameException|UnsupportedCharsetException unused) { // UnsupportedEncodingException should be thrown throw new UnsupportedEncodingException(csn); } } private static final Appendable nonNullAppendable(Appendable a) { if (a == null) return new StringBuilder(); return a; } /* Private constructors */ private Formatter(Locale l, Appendable a) { this.a = a; this.l = l; this.zero = getZero(l); } private Formatter(Charset charset, Locale l, File file) throws FileNotFoundException { this(l, new BufferedWriter(new OutputStreamWriter(new FileOutputStream(file), charset))); } /** * Constructs a new formatter. * *
The destination of the formatted output is a {@link StringBuilder} * which may be retrieved by invoking {@link #out out()} and whose * current content may be converted into a string by invoking {@link * #toString toString()}. The locale used is the {@linkplain * Locale#getDefault() default locale} for this instance of the Java * virtual machine. */ public Formatter() { this(Locale.getDefault(Locale.Category.FORMAT), new StringBuilder()); } /** * Constructs a new formatter with the specified destination. * *
The locale used is the {@linkplain Locale#getDefault() default * locale} for this instance of the Java virtual machine. * * @param a * Destination for the formatted output. If {@code a} is * {@code null} then a {@link StringBuilder} will be created. */ public Formatter(Appendable a) { this(Locale.getDefault(Locale.Category.FORMAT), nonNullAppendable(a)); } /** * Constructs a new formatter with the specified locale. * *
The destination of the formatted output is a {@link StringBuilder} * which may be retrieved by invoking {@link #out out()} and whose current * content may be converted into a string by invoking {@link #toString * toString()}. * * @param l * The {@linkplain java.util.Locale locale} to apply during * formatting. If {@code l} is {@code null} then no localization * is applied. */ public Formatter(Locale l) { this(l, new StringBuilder()); } /** * Constructs a new formatter with the specified destination and locale. * * @param a * Destination for the formatted output. If {@code a} is * {@code null} then a {@link StringBuilder} will be created. * * @param l * The {@linkplain java.util.Locale locale} to apply during * formatting. If {@code l} is {@code null} then no localization * is applied. */ public Formatter(Appendable a, Locale l) { this(l, nonNullAppendable(a)); } /** * Constructs a new formatter with the specified file name. * *
The charset used is the {@linkplain * java.nio.charset.Charset#defaultCharset() default charset} for this * instance of the Java virtual machine. * *
The locale used is the {@linkplain Locale#getDefault() default * locale} for this instance of the Java virtual machine. * * @param fileName * The name of the file to use as the destination of this * formatter. If the file exists then it will be truncated to * zero size; otherwise, a new file will be created. The output * will be written to the file and is buffered. * * @throws SecurityException * If a security manager is present and {@link * SecurityManager#checkWrite checkWrite(fileName)} denies write * access to the file * * @throws FileNotFoundException * If the given file name does not denote an existing, writable * regular file and a new regular file of that name cannot be * created, or if some other error occurs while opening or * creating the file */ public Formatter(String fileName) throws FileNotFoundException { this(Locale.getDefault(Locale.Category.FORMAT), new BufferedWriter(new OutputStreamWriter(new FileOutputStream(fileName)))); } /** * Constructs a new formatter with the specified file name and charset. * *
The locale used is the {@linkplain Locale#getDefault default * locale} for this instance of the Java virtual machine. * * @param fileName * The name of the file to use as the destination of this * formatter. If the file exists then it will be truncated to * zero size; otherwise, a new file will be created. The output * will be written to the file and is buffered. * * @param csn * The name of a supported {@linkplain java.nio.charset.Charset * charset} * * @throws FileNotFoundException * If the given file name does not denote an existing, writable * regular file and a new regular file of that name cannot be * created, or if some other error occurs while opening or * creating the file * * @throws SecurityException * If a security manager is present and {@link * SecurityManager#checkWrite checkWrite(fileName)} denies write * access to the file * * @throws UnsupportedEncodingException * If the named charset is not supported */ public Formatter(String fileName, String csn) throws FileNotFoundException, UnsupportedEncodingException { this(fileName, csn, Locale.getDefault(Locale.Category.FORMAT)); } /** * Constructs a new formatter with the specified file name, charset, and * locale. * * @param fileName * The name of the file to use as the destination of this * formatter. If the file exists then it will be truncated to * zero size; otherwise, a new file will be created. The output * will be written to the file and is buffered. * * @param csn * The name of a supported {@linkplain java.nio.charset.Charset * charset} * * @param l * The {@linkplain java.util.Locale locale} to apply during * formatting. If {@code l} is {@code null} then no localization * is applied. * * @throws FileNotFoundException * If the given file name does not denote an existing, writable * regular file and a new regular file of that name cannot be * created, or if some other error occurs while opening or * creating the file * * @throws SecurityException * If a security manager is present and {@link * SecurityManager#checkWrite checkWrite(fileName)} denies write * access to the file * * @throws UnsupportedEncodingException * If the named charset is not supported */ public Formatter(String fileName, String csn, Locale l) throws FileNotFoundException, UnsupportedEncodingException { this(toCharset(csn), l, new File(fileName)); } /** * Constructs a new formatter with the specified file. * *
The charset used is the {@linkplain * java.nio.charset.Charset#defaultCharset() default charset} for this * instance of the Java virtual machine. * *
The locale used is the {@linkplain Locale#getDefault() default * locale} for this instance of the Java virtual machine. * * @param file * The file to use as the destination of this formatter. If the * file exists then it will be truncated to zero size; otherwise, * a new file will be created. The output will be written to the * file and is buffered. * * @throws SecurityException * If a security manager is present and {@link * SecurityManager#checkWrite checkWrite(file.getPath())} denies * write access to the file * * @throws FileNotFoundException * If the given file object does not denote an existing, writable * regular file and a new regular file of that name cannot be * created, or if some other error occurs while opening or * creating the file */ public Formatter(File file) throws FileNotFoundException { this(Locale.getDefault(Locale.Category.FORMAT), new BufferedWriter(new OutputStreamWriter(new FileOutputStream(file)))); } /** * Constructs a new formatter with the specified file and charset. * *
The locale used is the {@linkplain Locale#getDefault default * locale} for this instance of the Java virtual machine. * * @param file * The file to use as the destination of this formatter. If the * file exists then it will be truncated to zero size; otherwise, * a new file will be created. The output will be written to the * file and is buffered. * * @param csn * The name of a supported {@linkplain java.nio.charset.Charset * charset} * * @throws FileNotFoundException * If the given file object does not denote an existing, writable * regular file and a new regular file of that name cannot be * created, or if some other error occurs while opening or * creating the file * * @throws SecurityException * If a security manager is present and {@link * SecurityManager#checkWrite checkWrite(file.getPath())} denies * write access to the file * * @throws UnsupportedEncodingException * If the named charset is not supported */ public Formatter(File file, String csn) throws FileNotFoundException, UnsupportedEncodingException { this(file, csn, Locale.getDefault(Locale.Category.FORMAT)); } /** * Constructs a new formatter with the specified file, charset, and * locale. * * @param file * The file to use as the destination of this formatter. If the * file exists then it will be truncated to zero size; otherwise, * a new file will be created. The output will be written to the * file and is buffered. * * @param csn * The name of a supported {@linkplain java.nio.charset.Charset * charset} * * @param l * The {@linkplain java.util.Locale locale} to apply during * formatting. If {@code l} is {@code null} then no localization * is applied. * * @throws FileNotFoundException * If the given file object does not denote an existing, writable * regular file and a new regular file of that name cannot be * created, or if some other error occurs while opening or * creating the file * * @throws SecurityException * If a security manager is present and {@link * SecurityManager#checkWrite checkWrite(file.getPath())} denies * write access to the file * * @throws UnsupportedEncodingException * If the named charset is not supported */ public Formatter(File file, String csn, Locale l) throws FileNotFoundException, UnsupportedEncodingException { this(toCharset(csn), l, file); } /** * Constructs a new formatter with the specified print stream. * *
The locale used is the {@linkplain Locale#getDefault() default * locale} for this instance of the Java virtual machine. * *
Characters are written to the given {@link java.io.PrintStream * PrintStream} object and are therefore encoded using that object's * charset. * * @param ps * The stream to use as the destination of this formatter. */ public Formatter(PrintStream ps) { this(Locale.getDefault(Locale.Category.FORMAT), (Appendable)Objects.requireNonNull(ps)); } /** * Constructs a new formatter with the specified output stream. * *
The charset used is the {@linkplain * java.nio.charset.Charset#defaultCharset() default charset} for this * instance of the Java virtual machine. * *
The locale used is the {@linkplain Locale#getDefault() default * locale} for this instance of the Java virtual machine. * * @param os * The output stream to use as the destination of this formatter. * The output will be buffered. */ public Formatter(OutputStream os) { this(Locale.getDefault(Locale.Category.FORMAT), new BufferedWriter(new OutputStreamWriter(os))); } /** * Constructs a new formatter with the specified output stream and * charset. * *
The locale used is the {@linkplain Locale#getDefault default * locale} for this instance of the Java virtual machine. * * @param os * The output stream to use as the destination of this formatter. * The output will be buffered. * * @param csn * The name of a supported {@linkplain java.nio.charset.Charset * charset} * * @throws UnsupportedEncodingException * If the named charset is not supported */ public Formatter(OutputStream os, String csn) throws UnsupportedEncodingException { this(os, csn, Locale.getDefault(Locale.Category.FORMAT)); } /** * Constructs a new formatter with the specified output stream, charset, * and locale. * * @param os * The output stream to use as the destination of this formatter. * The output will be buffered. * * @param csn * The name of a supported {@linkplain java.nio.charset.Charset * charset} * * @param l * The {@linkplain java.util.Locale locale} to apply during * formatting. If {@code l} is {@code null} then no localization * is applied. * * @throws UnsupportedEncodingException * If the named charset is not supported */ public Formatter(OutputStream os, String csn, Locale l) throws UnsupportedEncodingException { this(l, new BufferedWriter(new OutputStreamWriter(os, csn))); } private static char getZero(Locale l) { if ((l != null) && !l.equals(Locale.US)) { DecimalFormatSymbols dfs = DecimalFormatSymbols.getInstance(l); return dfs.getZeroDigit(); } else { return '0'; } } /** * Returns the locale set by the construction of this formatter. * *
The {@link #format(java.util.Locale,String,Object...) format} method * for this object which has a locale argument does not change this value. * * @return {@code null} if no localization is applied, otherwise a * locale * * @throws FormatterClosedException * If this formatter has been closed by invoking its {@link * #close()} method */ public Locale locale() { ensureOpen(); return l; } /** * Returns the destination for the output. * * @return The destination for the output * * @throws FormatterClosedException * If this formatter has been closed by invoking its {@link * #close()} method */ public Appendable out() { ensureOpen(); return a; } /** * Returns the result of invoking {@code toString()} on the destination * for the output. For example, the following code formats text into a * {@link StringBuilder} then retrieves the resultant string: * *
* ** Formatter f = new Formatter(); * f.format("Last reboot at %tc", lastRebootDate); * String s = f.toString(); * // -> s == "Last reboot at Sat Jan 01 00:00:00 PST 2000" *
An invocation of this method behaves in exactly the same way as the * invocation * *
* out().toString()* *
Depending on the specification of {@code toString} for the {@link * Appendable}, the returned string may or may not contain the characters * written to the destination. For instance, buffers typically return * their contents in {@code toString()}, but streams cannot since the * data is discarded. * * @return The result of invoking {@code toString()} on the destination * for the output * * @throws FormatterClosedException * If this formatter has been closed by invoking its {@link * #close()} method */ public String toString() { ensureOpen(); return a.toString(); } /** * Flushes this formatter. If the destination implements the {@link * java.io.Flushable} interface, its {@code flush} method will be invoked. * *
Flushing a formatter writes any buffered output in the destination * to the underlying stream. * * @throws FormatterClosedException * If this formatter has been closed by invoking its {@link * #close()} method */ public void flush() { ensureOpen(); if (a instanceof Flushable) { try { ((Flushable)a).flush(); } catch (IOException ioe) { lastException = ioe; } } } /** * Closes this formatter. If the destination implements the {@link * java.io.Closeable} interface, its {@code close} method will be invoked. * *
Closing a formatter allows it to release resources it may be holding * (such as open files). If the formatter is already closed, then invoking * this method has no effect. * *
Attempting to invoke any methods except {@link #ioException()} in * this formatter after it has been closed will result in a {@link * FormatterClosedException}. */ public void close() { if (a == null) return; try { if (a instanceof Closeable) ((Closeable)a).close(); } catch (IOException ioe) { lastException = ioe; } finally { a = null; } } private void ensureOpen() { if (a == null) throw new FormatterClosedException(); } /** * Returns the {@code IOException} last thrown by this formatter's {@link * Appendable}. * *
If the destination's {@code append()} method never throws
* {@code IOException}, then this method will always return {@code null}.
*
* @return The last exception thrown by the Appendable or {@code null} if
* no such exception exists.
*/
public IOException ioException() {
return lastException;
}
/**
* Writes a formatted string to this object's destination using the
* specified format string and arguments. The locale used is the one
* defined during the construction of this formatter.
*
* @param format
* A format string as described in Format string
* syntax.
*
* @param args
* Arguments referenced by the format specifiers in the format
* string. If there are more arguments than format specifiers, the
* extra arguments are ignored. The maximum number of arguments is
* limited by the maximum dimension of a Java array as defined by
* The Java™ Virtual Machine Specification.
*
* @throws IllegalFormatException
* If a format string contains an illegal syntax, a format
* specifier that is incompatible with the given arguments,
* insufficient arguments given the format string, or other
* illegal conditions. For specification of all possible
* formatting errors, see the Details
* section of the formatter class specification.
*
* @throws FormatterClosedException
* If this formatter has been closed by invoking its {@link
* #close()} method
*
* @return This formatter
*/
public Formatter format(String format, Object ... args) {
return format(l, format, args);
}
/**
* Writes a formatted string to this object's destination using the
* specified locale, format string, and arguments.
*
* @param l
* The {@linkplain java.util.Locale locale} to apply during
* formatting. If {@code l} is {@code null} then no localization
* is applied. This does not change this object's locale that was
* set during construction.
*
* @param format
* A format string as described in Format string
* syntax
*
* @param args
* Arguments referenced by the format specifiers in the format
* string. If there are more arguments than format specifiers, the
* extra arguments are ignored. The maximum number of arguments is
* limited by the maximum dimension of a Java array as defined by
* The Java™ Virtual Machine Specification.
*
* @throws IllegalFormatException
* If a format string contains an illegal syntax, a format
* specifier that is incompatible with the given arguments,
* insufficient arguments given the format string, or other
* illegal conditions. For specification of all possible
* formatting errors, see the Details
* section of the formatter class specification.
*
* @throws FormatterClosedException
* If this formatter has been closed by invoking its {@link
* #close()} method
*
* @return This formatter
*/
public Formatter format(Locale l, String format, Object ... args) {
ensureOpen();
// index of last argument referenced
int last = -1;
// last ordinary index
int lasto = -1;
FormatString[] fsa = parse(format);
for (int i = 0; i < fsa.length; i++) {
FormatString fs = fsa[i];
int index = fs.index();
try {
switch (index) {
case -2: // fixed string, "%n", or "%%"
fs.print(null, l);
break;
case -1: // relative index
if (last < 0 || (args != null && last > args.length - 1))
throw new MissingFormatArgumentException(fs.toString());
fs.print((args == null ? null : args[last]), l);
break;
case 0: // ordinary index
lasto++;
last = lasto;
if (args != null && lasto > args.length - 1)
throw new MissingFormatArgumentException(fs.toString());
fs.print((args == null ? null : args[lasto]), l);
break;
default: // explicit index
last = index - 1;
if (args != null && last > args.length - 1)
throw new MissingFormatArgumentException(fs.toString());
fs.print((args == null ? null : args[last]), l);
break;
}
} catch (IOException x) {
lastException = x;
}
}
return this;
}
// %[argument_index$][flags][width][.precision][t]conversion
private static final String formatSpecifier
= "%(\\d+\\$)?([-#+ 0,(\\<]*)?(\\d+)?(\\.\\d+)?([tT])?([a-zA-Z%])";
private static Pattern fsPattern = Pattern.compile(formatSpecifier);
/**
* Finds format specifiers in the format string.
*/
private FormatString[] parse(String s) {
ArrayList