org.python.core.stringlib

Class FloatFormatter

java.lang.Object

org.python.core.stringlib.InternalFormat.Formatter

org.python.core.stringlib.FloatFormatter

All Implemented Interfaces:

java.lang.Appendable

public class FloatFormatter
extends InternalFormat.Formatter

A class that provides the implementation of floating-point formatting. In a limited way, it acts like a StringBuilder to which text and one or more numbers may be appended, formatted according to the format specifier supplied at construction. These are ephemeral objects that are not, on their own, thread safe.

Field Summary

Fields inherited from class org.python.core.stringlib.InternalFormat.Formatter

bytes, lenSign, lenWhole, mark, result, spec, start

Constructor Summary

Constructors

Constructor and Description
FloatFormatter(InternalFormat.Spec spec) Construct the formatter from a specification, allocating a buffer internally for the result.
FloatFormatter(java.lang.StringBuilder result, InternalFormat.Spec spec) Construct the formatter from a client-supplied buffer, to which the result will be appended, and a specification.

Method Summary

Modifier and Type	Method and Description
FloatFormatter	append(char c)
FloatFormatter	append(java.lang.CharSequence csq)
FloatFormatter	append(java.lang.CharSequence csq, int start, int end)
FloatFormatter	format(double value) Format a floating-point number according to the specification represented by this FloatFormatter.
FloatFormatter	format(double value, java.lang.String positivePrefix) Format a floating-point number according to the specification represented by this FloatFormatter.
protected void	reset() Clear the instance variables describing the latest object in InternalFormat.Formatter.result, ready to receive a new one.
protected int[]	sectionLengths() Supports InternalFormat.Formatter.toString() by returning the lengths of the successive sections in the result buffer, used for navigation relative to InternalFormat.Formatter.start.
void	setMinFracDigits(int minFracDigits) Override the default truncation behaviour for the specification originally supplied.
static int	size(InternalFormat.Spec spec) Recommend a buffer size for a given specification, assuming one float is converted.
protected void	uppercase() Convert just the letters in the representation of the current number (in InternalFormat.Formatter.result) to upper case.

Methods inherited from class org.python.core.stringlib.InternalFormat.Formatter

alignmentNotAllowed, alternateFormNotAllowed, alternateFormNotAllowed, getPyResult, getResult, groupDigits, isBytes, makeSpaceAt, notAllowed, notAllowed, pad, pad, precisionNotAllowed, precisionTooLarge, setBytes, setStart, signNotAllowed, toString, unknownFormat, zeroPadAfterSignWithGroupingFixup, zeroPaddingNotAllowed

Methods inherited from class java.lang.Object

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

Constructor Detail

FloatFormatter

public FloatFormatter(java.lang.StringBuilder result,
                      InternalFormat.Spec spec)

Construct the formatter from a client-supplied buffer, to which the result will be appended, and a specification. Sets InternalFormat.Formatter.mark to the end of the buffer.

Parameters:

result - destination buffer

spec - parsed conversion specification

FloatFormatter

public FloatFormatter(InternalFormat.Spec spec)

Construct the formatter from a specification, allocating a buffer internally for the result.

Parameters:

spec - parsed conversion specification

Method Detail

size

public static int size(InternalFormat.Spec spec)

Recommend a buffer size for a given specification, assuming one float is converted. This will be a "right" answer for e and g-format, and for f-format with values up to 9,999,999.

Parameters:

spec - parsed conversion specification

setMinFracDigits

public void setMinFracDigits(int minFracDigits)

Override the default truncation behaviour for the specification originally supplied. Some formats remove trailing zero digits, trimming to zero or one. Set member minFracDigits, to modify this behaviour.

Parameters:

minFracDigits - if <0 prevent truncation; if ≥0 the minimum number of fractional digits; when this is zero, and all fractional digits are zero, the decimal point will also be removed.

reset

protected void reset()

Description copied from class: InternalFormat.Formatter

Clear the instance variables describing the latest object in InternalFormat.Formatter.result, ready to receive a new one. This is called from InternalFormat.Formatter.setStart(). Subclasses override this method and call InternalFormat.Formatter.setStart() at the start of their format method.

Overrides:

reset in class InternalFormat.Formatter

sectionLengths

protected int[] sectionLengths()

Description copied from class: InternalFormat.Formatter

Supports InternalFormat.Formatter.toString() by returning the lengths of the successive sections in the result buffer, used for navigation relative to InternalFormat.Formatter.start. The toString method shows a '|' character between each section when it prints out the buffer. Override this when you define more lengths in the subclass.

Overrides:

sectionLengths in class InternalFormat.Formatter

Returns:

the lengths of the successive sections

append

public FloatFormatter append(char c)

Specified by:

append in interface java.lang.Appendable

Overrides:

append in class InternalFormat.Formatter

append

public FloatFormatter append(java.lang.CharSequence csq)

Specified by:

append in interface java.lang.Appendable

Overrides:

append in class InternalFormat.Formatter

append

public FloatFormatter append(java.lang.CharSequence csq,
                             int start,
                             int end)
                      throws java.lang.IndexOutOfBoundsException

Specified by:

append in interface java.lang.Appendable

Overrides:

append in class InternalFormat.Formatter

Throws:

java.lang.IndexOutOfBoundsException

format

public FloatFormatter format(double value)

Format a floating-point number according to the specification represented by this FloatFormatter.

Parameters:

value - to convert

Returns:

this object

format

public FloatFormatter format(double value,
                             java.lang.String positivePrefix)

Format a floating-point number according to the specification represented by this FloatFormatter. The conversion type, precision, and flags for grouping or percentage are dealt with here. At the point this is used, we know the InternalFormat.Formatter.spec is one of the floating-point types. This entry point allows explicit control of the prefix of positive numbers, overriding defaults for the format type.

Parameters:

value - to convert

positivePrefix - to use before positive values (e.g. "+") or null to default to ""

Returns:

this object

uppercase

protected void uppercase()

Convert just the letters in the representation of the current number (in InternalFormat.Formatter.result) to upper case. (That's the exponent marker or the "inf" or "nan".)

Overrides:

uppercase in class InternalFormat.Formatter