Package elki.utilities.io

Class ParseUtil

java.lang.Object

elki.utilities.io.ParseUtil

public final class ParseUtil
extends java.lang.Object

Helper functionality for parsing.

This class is fairly optimized. Because exceptions frequently occur in parsing (e.g., when trying to parse a text as float), this implementation avoids allocating exceptions and stack traces in these cases, and uses static instances instead. By setting the logging level for the ParseUtil class to FINE, the backtraces can still be obtained for development. But usually you will want to catch this exception and instead throw your own with additional context information of the value that failed to parse.

Since:

0.7.5

Author:

Erich Schubert

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private static class	ParseUtil.PreallocatedException	Preallocated exception.

Field Summary

Fields

Modifier and Type	Field	Description
static java.lang.NumberFormatException	EMPTY_STRING	Preallocated exceptions.
static java.lang.NumberFormatException	EXPONENT_OVERFLOW	Preallocated exceptions.
private static int	INFINITY_LENGTH	Length of pattern
private static char[]	INFINITY_PATTERN	Infinity pattern, with any capitalization
static java.lang.NumberFormatException	INVALID_EXPONENT	Preallocated exceptions.
private static Logging	LOG	Logging helper.
static java.lang.NumberFormatException	NOT_A_NUMBER	Preallocated exceptions.
static java.lang.NumberFormatException	PRECISION_OVERFLOW	Preallocated exceptions.
static java.lang.NumberFormatException	TRAILING_CHARACTERS	Preallocated exceptions.

Constructor Summary

Constructors

Modifier	Constructor	Description
private	ParseUtil()	Private constructor.

Method Summary

Modifier and Type	Method	Description
private static boolean	matchInf(byte[] str, byte firstchar, int start, int end)	Match "inf", "infinity" in a number of different capitalizations.
private static boolean	matchInf(java.lang.CharSequence str, char firstchar, int start, int end)	Match "inf", "infinity" in a number of different capitalizations.
private static boolean	matchNaN(byte[] str, byte firstchar, int start, int end)	Match "NaN" in a number of different capitalizations.
private static boolean	matchNaN(java.lang.CharSequence str, char firstchar, int start, int end)	Match "NaN" in a number of different capitalizations.
static double	parseDouble(byte[] str, int start, int end)	Parse a double from a character sequence.
static double	parseDouble(java.lang.CharSequence str)	Parse a double from a character sequence.
static double	parseDouble(java.lang.CharSequence str, int start, int end)	Parse a double from a character sequence.
static int	parseIntBase10(java.lang.CharSequence str)	Parse an integer from a character sequence.
static int	parseIntBase10(java.lang.CharSequence str, int start, int end)	Parse an integer from a character sequence.
static long	parseLongBase10(java.lang.CharSequence str)	Parse a long integer from a character sequence.
static long	parseLongBase10(java.lang.CharSequence str, int start, int end)	Parse a long integer from a character sequence.

Methods inherited from class java.lang.Object

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

Field Detail

LOG

private static final Logging LOG

Logging helper.

EMPTY_STRING

public static final java.lang.NumberFormatException EMPTY_STRING

Preallocated exceptions.

EXPONENT_OVERFLOW

public static final java.lang.NumberFormatException EXPONENT_OVERFLOW

Preallocated exceptions.

INVALID_EXPONENT

public static final java.lang.NumberFormatException INVALID_EXPONENT

Preallocated exceptions.

TRAILING_CHARACTERS

public static final java.lang.NumberFormatException TRAILING_CHARACTERS

Preallocated exceptions.

PRECISION_OVERFLOW

public static final java.lang.NumberFormatException PRECISION_OVERFLOW

Preallocated exceptions.

NOT_A_NUMBER

public static final java.lang.NumberFormatException NOT_A_NUMBER

Preallocated exceptions.

INFINITY_PATTERN

private static final char[] INFINITY_PATTERN

Infinity pattern, with any capitalization

INFINITY_LENGTH

private static final int INFINITY_LENGTH

Length of pattern

Constructor Detail

ParseUtil

private ParseUtil()

Private constructor. Static methods only.

Method Detail

parseDouble

public static double parseDouble(byte[] str,
                                 int start,
                                 int end)

Parse a double from a character sequence.

In contrast to Javas Double.parseDouble(java.lang.String), this will not create an object and thus is expected to put less load on the garbage collector. It will accept some more spellings of NaN and infinity, thus removing the need for checking for these independently.

Parameters:

str - String

start - Begin

end - End

Returns:

Double value

parseDouble

public static double parseDouble(java.lang.CharSequence str)

Parse a double from a character sequence.

In contrast to Javas Double.parseDouble(java.lang.String), this will not create an object and thus is expected to put less load on the garbage collector. It will accept some more spellings of NaN and infinity, thus removing the need for checking for these independently.

Parameters:

str - String

Returns:

Double value

parseDouble

public static double parseDouble(java.lang.CharSequence str,
                                 int start,
                                 int end)

Parse a double from a character sequence.

In contrast to Javas Double.parseDouble(java.lang.String), this will not create an object and thus is expected to put less load on the garbage collector. It will accept some more spellings of NaN and infinity, thus removing the need for checking for these independently.

Parameters:

str - String

start - Begin

end - End

Returns:

Double value

parseLongBase10

public static long parseLongBase10(java.lang.CharSequence str)

Parse a long integer from a character sequence.

Parameters:

str - String

Returns:

Long value

parseLongBase10

public static long parseLongBase10(java.lang.CharSequence str,
                                   int start,
                                   int end)

Parse a long integer from a character sequence.

Parameters:

str - String

start - Begin

end - End

Returns:

Long value

parseIntBase10

public static int parseIntBase10(java.lang.CharSequence str)

Parse an integer from a character sequence.

Parameters:

str - String

Returns:

Int value

parseIntBase10

public static int parseIntBase10(java.lang.CharSequence str,
                                 int start,
                                 int end)

Parse an integer from a character sequence.

Parameters:

str - String

start - Begin

end - End

Returns:

int value

matchInf

private static boolean matchInf(byte[] str,
                                byte firstchar,
                                int start,
                                int end)

Match "inf", "infinity" in a number of different capitalizations.

Parameters:

str - String to match

firstchar - First character

start - Interval begin

end - Interval end

Returns:

true when infinity was recognized.

matchInf

private static boolean matchInf(java.lang.CharSequence str,
                                char firstchar,
                                int start,
                                int end)

Match "inf", "infinity" in a number of different capitalizations.

Parameters:

str - String to match

firstchar - First character

start - Interval begin

end - Interval end

Returns:

true when infinity was recognized.

matchNaN

private static boolean matchNaN(byte[] str,
                                byte firstchar,
                                int start,
                                int end)

Match "NaN" in a number of different capitalizations.

Parameters:

str - String to match

firstchar - First character

start - Interval begin

end - Interval end

Returns:

true when NaN was recognized.

matchNaN

private static boolean matchNaN(java.lang.CharSequence str,
                                char firstchar,
                                int start,
                                int end)

Match "NaN" in a number of different capitalizations.

Parameters:

str - String to match

firstchar - First character

start - Interval begin

end - Interval end

Returns:

true when NaN was recognized.