de.lmu.ifi.dbs.elki.utilities.io

Class FormatUtil

java.lang.Object

de.lmu.ifi.dbs.elki.utilities.io.FormatUtil

public final class FormatUtil
extends java.lang.Object

Utility methods for output formatting of various number objects

FIXME: Handle formatting of infinity and NaN better.

Since:

0.2

Author:

Arthur Zimek, Erich Schubert

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	NEWLINE The system newline setting.
static java.text.NumberFormat	NF Dynamic number formatter, but with language constraint.
static java.text.NumberFormat	NF0 Number Formatter (0 digits) for output purposes.
static java.text.NumberFormat	NF16 Number Formatter (16 digits) for output purposes.
static java.text.NumberFormat	NF2 Number Formatter (2 digits) for output purposes.
static java.text.NumberFormat	NF3 Number Formatter (3 digits) for output purposes.
static java.text.NumberFormat	NF4 Number Formatter (4 digits) for output purposes.
static java.text.NumberFormat	NF6 Number Formatter (6 digits) for output purposes.
static java.text.NumberFormat	NF8 Number Formatter (8 digits) for output purposes.
static char	NONBREAKING_SPACE Non-breaking unicode space character.
private static char[]	SPACEPADDING Buffer for whitespace padding.
private static int[]	TIME_UNIT_DIGITS The number of digits used for formatting
private static java.lang.String[]	TIME_UNIT_NAMES The strings used in serialization
private static long[]	TIME_UNIT_SIZES The time unit sizes: ms, s, m, h, d; all in ms.
private static java.lang.String	WHITESPACE_BUFFER Whitespace.
private static int	WHITESPACE_BUFFER_LENGTH Length of the whitespace buffer.
private static int	width Terminal width cache.
private static char[]	ZEROPADDING Buffer for zero padding.

Constructor Summary

Constructors

Modifier	Constructor and Description
private	FormatUtil() Private constructor.

Method Summary

Modifier and Type	Method and Description
static java.lang.StringBuilder	appendSpace(java.lang.StringBuilder buf, int spaces) Append whitespace to a buffer.
static java.lang.StringBuilder	appendZeros(java.lang.StringBuilder buf, int zeros) Append zeros to a buffer.
static boolean	endsWith(java.lang.CharSequence buf, java.lang.CharSequence end) Similar to String.endsWith(String) but for buffers.
static int	findSplitpoint(java.lang.String s, int width) Find the first space before position w or if there is none after w.
static java.lang.String	format(boolean b) Formats the boolean b.
static java.lang.String	format(boolean[] b, java.lang.String sep) Formats the boolean array b with ',' as separator.
static java.lang.String	format(byte[] a) Formats the byte array a for printing purposes.
static java.lang.String	format(java.util.Collection<java.lang.String> d, java.lang.String sep) Formats the String collection with the specified separator.
static java.lang.String	format(double[] d) Formats the double array d with ', ' as separator and default precision.
static java.lang.String	format(double[][] d) Formats the double array d with ',' as separator and 2 fraction digits.
static java.lang.String	format(double[][] m, int w, int d, java.lang.String pre, java.lang.String pos, java.lang.String csep) Returns a string representation of this matrix.
static java.lang.String	format(double[][] m, java.text.NumberFormat nf) returns String-representation of Matrix.
static java.lang.String	format(double[][] m, java.lang.String pre) Returns a string representation of this matrix.
static java.lang.String	format(double[][] d, java.lang.String pre, java.lang.String pos, java.lang.String csep, java.text.NumberFormat nf) Formats the array of double arrays d with 'the specified separators and fraction digits.
static java.lang.String	format(double[] v, int w, int d) Returns a string representation of this vector.
static java.lang.String	format(double[] d, java.text.NumberFormat nf) Formats the double array d with the specified number format.
static java.lang.String	format(double[] d, java.lang.String sep) Formats the double array d with the specified separator.
static java.lang.String	format(double[] d, java.lang.String sep, java.text.NumberFormat nf) Formats the double array d with the specified number format.
static java.lang.String	format(float[] f) Formats the float array f with ',' as separator and default precision.
static java.lang.String	format(float[] d, java.lang.String sep) Formats the float array d with the specified number format.
static java.lang.String	format(float[] d, java.lang.String sep, java.text.NumberFormat nf) Formats the float array d with the specified number format.
static java.lang.String	format(int[] a) Formats the int array a for printing purposes.
static java.lang.String	format(int[] a, java.lang.String sep) Formats the int array a for printing purposes.
static java.lang.String	format(long[] a) Formats the long array a for printing purposes.
static java.lang.String	format(java.lang.String[] d, java.lang.String sep) Formats the string array d with the specified separator.
static java.lang.StringBuilder	formatBit(java.lang.StringBuilder buf, boolean b) Format a boolean value as string "1" or "0".
static java.lang.String	formatTimeDelta(long time, java.lang.CharSequence sep) Formats a time delta in human readable format.
static java.lang.StringBuilder	formatTo(java.lang.StringBuilder buf, boolean b) Format a boolean value as string "true" or "false".
static java.lang.StringBuilder	formatTo(java.lang.StringBuilder buf, boolean[] d, java.lang.String sep) Formats the boolean array d.
static java.lang.StringBuilder	formatTo(java.lang.StringBuilder buf, byte[] d, java.lang.String sep) Formats the byte array d.
static java.lang.StringBuilder	formatTo(java.lang.StringBuilder buf, double[][] d, java.lang.String pre, java.lang.String pos, java.lang.String csep, java.text.NumberFormat nf) Formats the array of double arrays d with the specified separators and fraction digits.
static java.lang.StringBuilder	formatTo(java.lang.StringBuilder buf, double[] d, java.lang.String sep) Formats the double array d with the default number format.
static java.lang.StringBuilder	formatTo(java.lang.StringBuilder buf, double[] d, java.lang.String sep, java.text.NumberFormat nf) Formats the double array d with the specified number format.
static java.lang.StringBuilder	formatTo(java.lang.StringBuilder buf, float[] d, java.lang.String sep) Formats the float array d with the default number format.
static java.lang.StringBuilder	formatTo(java.lang.StringBuilder buf, float[] d, java.lang.String sep, java.text.NumberFormat nf) Formats the float array d with the specified number format.
static java.lang.StringBuilder	formatTo(java.lang.StringBuilder buf, int[] d, java.lang.String sep) Formats the int array d.
static java.lang.StringBuilder	formatTo(java.lang.StringBuilder buf, long[] d, java.lang.String sep) Formats the long array d.
static java.lang.StringBuilder	formatTo(java.lang.StringBuilder buf, short[] d, java.lang.String sep) Formats the short array d.
static int	getConsoleWidth() Get the width of the terminal window (on Unix xterms), with a default of 78 characters.
static java.text.NumberFormat	makeNumberFormat(int digits) Initialize a number format with ELKI standard options (US locale, no grouping).
private static int	nextPosition(int a, int b) Helper that is similar to Math.min(a,b), except that negative values are considered "invalid".
static java.lang.String	pad(java.lang.String o, int len) Pad a string to a given length by adding whitespace to the right.
static java.lang.String	padRightAligned(java.lang.String o, int len) Pad a string to a given length by adding whitespace to the left.
static java.util.List<java.lang.String>	splitAtLastBlank(java.lang.String s, int width) Splits the specified string at the last blank before width.
static int	stringSize(int x) Compute the number of characters needed to represent the integer x.
static int	stringSize(long x) Compute the number of characters needed to represent the integer x.
static java.lang.String	whitespace(int n) Returns a string with the specified number of whitespace.
static java.lang.StringBuilder	whitespace(java.lang.StringBuilder buf, int n) Returns a string with the specified number of whitespace.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

NF

public static final java.text.NumberFormat NF

Dynamic number formatter, but with language constraint.

NF0

public static final java.text.NumberFormat NF0

Number Formatter (0 digits) for output purposes.

NF2

public static final java.text.NumberFormat NF2

Number Formatter (2 digits) for output purposes.

NF3

public static final java.text.NumberFormat NF3

Number Formatter (3 digits) for output purposes.

NF4

public static final java.text.NumberFormat NF4

Number Formatter (4 digits) for output purposes.

NF6

public static final java.text.NumberFormat NF6

Number Formatter (6 digits) for output purposes.

NF8

public static final java.text.NumberFormat NF8

Number Formatter (8 digits) for output purposes.

NF16

public static final java.text.NumberFormat NF16

Number Formatter (16 digits) for output purposes.

WHITESPACE_BUFFER

private static final java.lang.String WHITESPACE_BUFFER

Whitespace. The string should cover the commonly used length.

See Also:

Constant Field Values

WHITESPACE_BUFFER_LENGTH

private static final int WHITESPACE_BUFFER_LENGTH

Length of the whitespace buffer.

NEWLINE

public static final java.lang.String NEWLINE

The system newline setting.

NONBREAKING_SPACE

public static final char NONBREAKING_SPACE

Non-breaking unicode space character.

TIME_UNIT_SIZES

private static final long[] TIME_UNIT_SIZES

The time unit sizes: ms, s, m, h, d; all in ms.

TIME_UNIT_NAMES

private static final java.lang.String[] TIME_UNIT_NAMES

The strings used in serialization

TIME_UNIT_DIGITS

private static final int[] TIME_UNIT_DIGITS

The number of digits used for formatting

width

private static int width

Terminal width cache.

ZEROPADDING

private static final char[] ZEROPADDING

Buffer for zero padding.

SPACEPADDING

private static final char[] SPACEPADDING

Buffer for whitespace padding.

Constructor Detail

FormatUtil

private FormatUtil()

Private constructor. Static methods only.

Method Detail

makeNumberFormat

public static java.text.NumberFormat makeNumberFormat(int digits)

Initialize a number format with ELKI standard options (US locale, no grouping).

Parameters:

digits - Number of digits to use

Returns:

Number format

format

public static java.lang.String format(double[] d)

Formats the double array d with ', ' as separator and default precision.

Parameters:

d - the double array to be formatted

Returns:

a String representing the double array d

format

public static java.lang.String format(double[] d,
                                      java.lang.String sep)

Formats the double array d with the specified separator.

Parameters:

d - the double array to be formatted

sep - separator between the single values of the array, e.g. ','

Returns:

a String representing the double array d

format

public static java.lang.String format(double[] d,
                                      java.text.NumberFormat nf)

Formats the double array d with the specified number format.

Parameters:

d - the double array to be formatted

nf - the number format to be used for formatting

Returns:

a String representing the double array d

format

public static java.lang.String format(double[] d,
                                      java.lang.String sep,
                                      java.text.NumberFormat nf)

Formats the double array d with the specified number format.

Parameters:

d - the double array to be formatted

sep - separator between the single values of the array, e.g. ','

nf - the number format to be used for formatting

Returns:

a String representing the double array d

format

public static java.lang.String format(double[] v,
                                      int w,
                                      int d)

Returns a string representation of this vector.

Parameters:

w - column width

d - number of digits after the decimal

Returns:

a string representation of this matrix

formatTo

public static java.lang.StringBuilder formatTo(java.lang.StringBuilder buf,
                                               double[] d,
                                               java.lang.String sep)

Formats the double array d with the default number format.

Parameters:

buf - String builder to append to

d - the double array to be formatted

sep - separator between the single values of the array, e.g. ','

Returns:

Output buffer buf

formatTo

public static java.lang.StringBuilder formatTo(java.lang.StringBuilder buf,
                                               double[] d,
                                               java.lang.String sep,
                                               java.text.NumberFormat nf)

Formats the double array d with the specified number format.

Parameters:

buf - String builder to append to

d - the double array to be formatted

sep - separator between the single values of the array, e.g. ','

nf - the number format to be used for formatting

Returns:

Output buffer buf

formatTo

public static java.lang.StringBuilder formatTo(java.lang.StringBuilder buf,
                                               float[] d,
                                               java.lang.String sep)

Formats the float array d with the default number format.

Parameters:

buf - String builder to append to

d - the float array to be formatted

sep - separator between the single values of the array, e.g. ','

Returns:

Output buffer buf

formatTo

public static java.lang.StringBuilder formatTo(java.lang.StringBuilder buf,
                                               float[] d,
                                               java.lang.String sep,
                                               java.text.NumberFormat nf)

Formats the float array d with the specified number format.

Parameters:

buf - String builder to append to

d - the float array to be formatted

sep - separator between the single values of the array, e.g. ','

nf - the number format to be used for formatting

Returns:

Output buffer buf

formatTo

public static java.lang.StringBuilder formatTo(java.lang.StringBuilder buf,
                                               int[] d,
                                               java.lang.String sep)

Formats the int array d.

Parameters:

buf - String builder to append to

d - the int array to be formatted

sep - separator between the single values of the array, e.g. ','

Returns:

Output buffer buf

formatTo

public static java.lang.StringBuilder formatTo(java.lang.StringBuilder buf,
                                               long[] d,
                                               java.lang.String sep)

Formats the long array d.

Parameters:

buf - String builder to append to

d - the long array to be formatted

sep - separator between the single values of the long array, e.g. ','

Returns:

Output buffer buf

formatTo

public static java.lang.StringBuilder formatTo(java.lang.StringBuilder buf,
                                               short[] d,
                                               java.lang.String sep)

Formats the short array d.

Parameters:

buf - String builder to append to

d - the int array to be formatted

sep - separator between the single values of the array, e.g. ','

Returns:

Output buffer buf

formatTo

public static java.lang.StringBuilder formatTo(java.lang.StringBuilder buf,
                                               byte[] d,
                                               java.lang.String sep)

Formats the byte array d.

Parameters:

buf - String builder to append to

d - the byte array to be formatted

sep - separator between the single values of the array, e.g. ','

Returns:

Output buffer buf

formatTo

public static java.lang.StringBuilder formatTo(java.lang.StringBuilder buf,
                                               boolean[] d,
                                               java.lang.String sep)

Formats the boolean array d.

Parameters:

buf - String builder to append to

d - the boolean array to be formatted

sep - separator between the single values of the array, e.g. ','

Returns:

Output buffer buf

formatTo

public static java.lang.StringBuilder formatTo(java.lang.StringBuilder buf,
                                               boolean b)

Format a boolean value as string "true" or "false".

Parameters:

buf - Buffer to append to

b - Boolean to Format

Returns:

Same buffer

formatBit

public static java.lang.StringBuilder formatBit(java.lang.StringBuilder buf,
                                                boolean b)

Format a boolean value as string "1" or "0".

Parameters:

buf - Buffer to append to

b - Boolean to Format

Returns:

Same buffer

format

public static java.lang.String format(float[] d,
                                      java.lang.String sep,
                                      java.text.NumberFormat nf)

Formats the float array d with the specified number format.

Parameters:

d - the float array to be formatted

sep - separator between the single values of the array, e.g. ','

nf - the number format to be used for formatting

Returns:

a String representing the double array d

format

public static java.lang.String format(float[] d,
                                      java.lang.String sep)

Formats the float array d with the specified number format.

Parameters:

d - the float array to be formatted

sep - separator between the single values of the array, e.g. ','

Returns:

a String representing the double array d

format

public static java.lang.String format(float[] f)

Formats the float array f with ',' as separator and default precision.

Parameters:

f - the float array to be formatted

Returns:

a String representing the float array f

format

public static java.lang.String format(int[] a,
                                      java.lang.String sep)

Formats the int array a for printing purposes.

Parameters:

a - the int array to be formatted

sep - the separator between the single values of the array, e.g. ','

Returns:

a String representing the int array a

format

public static java.lang.String format(int[] a)

Formats the int array a for printing purposes.

Parameters:

a - the int array to be formatted

Returns:

a String representing the int array a

format

public static java.lang.String format(long[] a)

Formats the long array a for printing purposes.

Parameters:

a - the long array to be formatted

Returns:

a String representing the long array a

format

public static java.lang.String format(byte[] a)

Formats the byte array a for printing purposes.

Parameters:

a - the byte array to be formatted

Returns:

a String representing the byte array a

format

public static java.lang.String format(boolean[] b,
                                      java.lang.String sep)

Formats the boolean array b with ',' as separator.

Parameters:

b - the boolean array to be formatted

sep - separator between the single values of the array, e.g. ','

Returns:

a String representing the boolean array b

format

public static java.lang.String format(boolean b)

Formats the boolean b.

Parameters:

b - the boolean to be formatted

Returns:

a String representing of the boolean b

formatTo

public static java.lang.StringBuilder formatTo(java.lang.StringBuilder buf,
                                               double[][] d,
                                               java.lang.String pre,
                                               java.lang.String pos,
                                               java.lang.String csep,
                                               java.text.NumberFormat nf)

Formats the array of double arrays d with the specified separators and fraction digits.

Parameters:

buf - Output buffer

d - the double array to be formatted

pre - Row prefix (e.g. " [")

pos - Row postfix (e.g. "]\n")

csep - Separator for columns (e.g. ", ")

nf - the number format to use

Returns:

Output buffer buf

format

public static java.lang.String format(double[][] d)

Formats the double array d with ',' as separator and 2 fraction digits.

Parameters:

d - the double array to be formatted

Returns:

a String representing the double array d

format

public static java.lang.String format(double[][] d,
                                      java.lang.String pre,
                                      java.lang.String pos,
                                      java.lang.String csep,
                                      java.text.NumberFormat nf)

Formats the array of double arrays d with 'the specified separators and fraction digits.

Parameters:

d - the double matrix to be formatted

pre - Row prefix (e.g. " [")

pos - Row postfix (e.g. "]\n")

csep - Separator for columns (e.g. ", ")

nf - the number format to use

Returns:

a String representing the double array d

format

public static java.lang.String format(double[][] m,
                                      int w,
                                      int d,
                                      java.lang.String pre,
                                      java.lang.String pos,
                                      java.lang.String csep)

Returns a string representation of this matrix.

Parameters:

w - column width

d - number of digits after the decimal

pre - Row prefix (e.g. " [")

pos - Row postfix (e.g. "]\n")

csep - Column separator (e.g. ", ")

Returns:

a string representation of this matrix

format

public static java.lang.String format(double[][] m,
                                      java.lang.String pre)

Returns a string representation of this matrix. In each line the specified String pre is prefixed.

Parameters:

pre - the prefix of each line

Returns:

a string representation of this matrix

format

public static java.lang.String format(double[][] m,
                                      java.text.NumberFormat nf)

returns String-representation of Matrix.

Parameters:

nf - NumberFormat to specify output precision

Returns:

String representation of this Matrix in precision as specified by given NumberFormat

format

public static java.lang.String format(java.util.Collection<java.lang.String> d,
                                      java.lang.String sep)

Formats the String collection with the specified separator.

Parameters:

d - the String collection to format

sep - separator between the single values of the array, e.g. ' '

Returns:

a String representing the String Collection d

format

public static java.lang.String format(java.lang.String[] d,
                                      java.lang.String sep)

Formats the string array d with the specified separator.

Parameters:

d - the string array to be formatted

sep - separator between the single values of the array, e.g. ','

Returns:

a String representing the string array d

findSplitpoint

public static int findSplitpoint(java.lang.String s,
                                 int width)

Find the first space before position w or if there is none after w.

Parameters:

s - String

width - Width

Returns:

index of best whitespace or -1 if no whitespace was found.

nextPosition

private static int nextPosition(int a,
                                int b)

Helper that is similar to Math.min(a,b), except that negative values are considered "invalid".

Parameters:

a - String position

b - String position

Returns:

Math.min(a,b) if a >= 0 and b >= 0, otherwise whichever is not negative.

splitAtLastBlank

public static java.util.List<java.lang.String> splitAtLastBlank(java.lang.String s,
                                                                int width)

Splits the specified string at the last blank before width. If there is no blank before the given width, it is split at the next.

Parameters:

s - the string to be split

width - int

Returns:

string fragments

whitespace

public static java.lang.String whitespace(int n)

Returns a string with the specified number of whitespace.

Parameters:

n - the number of whitespace characters

Returns:

a string with the specified number of blanks

whitespace

public static java.lang.StringBuilder whitespace(java.lang.StringBuilder buf,
                                                 int n)

Returns a string with the specified number of whitespace.

Parameters:

n - the number of whitespace characters

Returns:

a string with the specified number of blanks

pad

public static java.lang.String pad(java.lang.String o,
                                   int len)

Pad a string to a given length by adding whitespace to the right.

Parameters:

o - original string

len - destination length

Returns:

padded string of at least length len (and o otherwise)

padRightAligned

public static java.lang.String padRightAligned(java.lang.String o,
                                               int len)

Pad a string to a given length by adding whitespace to the left.

Parameters:

o - original string

len - destination length

Returns:

padded string of at least length len (and o otherwise)

getConsoleWidth

public static int getConsoleWidth()

Get the width of the terminal window (on Unix xterms), with a default of 78 characters.

Returns:

Terminal width

formatTimeDelta

public static java.lang.String formatTimeDelta(long time,
                                               java.lang.CharSequence sep)

Formats a time delta in human readable format.

Parameters:

time - time delta in ms

Returns:

Formatted string

appendZeros

public static java.lang.StringBuilder appendZeros(java.lang.StringBuilder buf,
                                                  int zeros)

Append zeros to a buffer.

Parameters:

buf - Buffer to append to

zeros - Number of zeros to append.

Returns:

Buffer

appendSpace

public static java.lang.StringBuilder appendSpace(java.lang.StringBuilder buf,
                                                  int spaces)

Append whitespace to a buffer.

Parameters:

buf - Buffer to append to

spaces - Number of spaces to append.

Returns:

Buffer

stringSize

public static int stringSize(int x)

Compute the number of characters needed to represent the integer x. Reimplementation of Long.stringSize(long), but public and without loop.

Parameters:

x - Integer value

Returns:

Number of digits needed

stringSize

public static int stringSize(long x)

Compute the number of characters needed to represent the integer x. Reimplementation of Long.stringSize(long), but public and without loop.

Parameters:

x - Integer value

Returns:

Number of digits needed

endsWith

public static boolean endsWith(java.lang.CharSequence buf,
                               java.lang.CharSequence end)

Similar to String.endsWith(String) but for buffers.

Parameters:

buf - Buffer

end - End

Returns:

true if the buffer ends with the given sequence