Package tech.units.indriya.format

Class EBNFUnitFormat

java.lang.Object

tech.units.indriya.format.AbstractUnitFormat

tech.units.indriya.format.EBNFUnitFormat

All Implemented Interfaces:

javax.measure.format.UnitFormat

public class EBNFUnitFormat
extends AbstractUnitFormat

This class represents the local neutral format.

Here is the grammar for Units in Extended Backus-Naur Form (EBNF)

Note that the grammar has been left-factored to be suitable for use by a top-down parser generator such as JavaCC

Lexical Entities:
<sign>	:=	"+" | "-"
<digit>	:=	"0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9"
<superscript_digit>	:=	"⁰" | "¹" | "²" | "³" | "⁴" | "⁵" | "⁶" | "⁷" | "⁸" | "⁹"
<integer>	:=	(<digit>)+
<number>	:=	(<sign>)? (<digit>)* (".")? (<digit>)+ (("e" | "E") (<sign>)? (<digit>)+)?
<exponent>	:=	( "^" ( <sign> )? <integer> ) | ( "^(" (<sign>)? <integer> ( "/" (<sign>)? <integer> )? ")" ) | ( <superscript_digit> )+
<initial_char>	:=	? Any Unicode character excluding the following: ASCII control & whitespace (\u0000 - \u0020), decimal digits '0'-'9', '(' (\u0028), ')' (\u0029), '*' (\u002A), '+' (\u002B), '-' (\u002D), '.' (\u002E), '/' (\u005C), ':' (\u003A), '^' (\u005E), '²' (\u00B2), '³' (\u00B3), '·' (\u00B7), '¹' (\u00B9), '⁰' (\u2070), '⁴' (\u2074), '⁵' (\u2075), '⁶' (\u2076), '⁷' (\u2077), '⁸' (\u2078), '⁹' (\u2079) ?
<unit_identifier>	:=	<initial_char> ( <initial_char> | <digit> )*
Non-Terminals:
<unit_expr>	:=	<mix_expr>
<mix_expr>	:=	<add_expr> ( ":" <add_expr> )*
<add_expr>	:=	( <number> <sign> )? <mul_expr> ( <sign> <number> )?
<mul_expr>	:=	<exponent_expr> ( ( ( "*" | "·" ) <exponent_expr> ) | ( "/" <exponent_expr> ) )*
<exponent_expr>	:=	( <atomic_expr> ( <exponent> )? ) | (<integer> "^" <atomic_expr>) | ( ( "log" ( <integer> )? ) | "ln" ) "(" <add_expr> ")" )
<atomic_expr>	:=	<number> | <unit_identifier> | ( "(" <add_expr> ")" )

Since:

1.0

Version:

1.5, $Date: 2020-03-02 $

Author:

Eric Russell, Werner Keil

Method Summary

Modifier and Type	Method	Description
Appendable	format(javax.measure.Unit<?> unit, Appendable appendable)	Formats the specified unit.
static EBNFUnitFormat	getInstance()	Returns the instance for the current default locale (non-ascii characters are allowed)
static EBNFUnitFormat	getInstance(SymbolMap symbols)	Returns an instance for the given symbol map.
protected SymbolMap	getSymbols()	Get the symbol map used by this instance to map between Units and Strings, etc...
javax.measure.Unit<?>	parse(CharSequence csq)
protected javax.measure.Unit<?>	parse(CharSequence csq, int index)	Parses a portion of the specified CharSequence from the specified position to produce a unit.
javax.measure.Unit<? extends javax.measure.Quantity<?>>	parse(CharSequence csq, ParsePosition cursor)	Parses a portion of the specified CharSequence from the specified position to produce a unit.
String	toString()

Methods inherited from class tech.units.indriya.format.AbstractUnitFormat

format, label

Methods inherited from class java.lang.Object

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

Methods inherited from interface javax.measure.format.UnitFormat

isLocaleSensitive

Method Detail

getInstance

public static EBNFUnitFormat getInstance()

Returns the instance for the current default locale (non-ascii characters are allowed)

getInstance

public static EBNFUnitFormat getInstance(SymbolMap symbols)

Returns an instance for the given symbol map.

getSymbols

protected SymbolMap getSymbols()

Get the symbol map used by this instance to map between Units and Strings, etc...

Returns:

SymbolMap the current symbol map

toString

public String toString()

Overrides:

toString in class Object

format

public Appendable format(javax.measure.Unit<?> unit,
                         Appendable appendable)
                  throws IOException

Description copied from class: AbstractUnitFormat

Formats the specified unit.

Specified by:

format in interface javax.measure.format.UnitFormat

Specified by:

format in class AbstractUnitFormat

Parameters:

unit - the unit to format.

appendable - the appendable destination.

Returns:

The appendable destination passed in as appendable, with formatted text appended.

Throws:

IOException - if an error occurs.

parse

public javax.measure.Unit<? extends javax.measure.Quantity<?>> parse(CharSequence csq,
                                                                     ParsePosition cursor)
                                                              throws javax.measure.format.MeasurementParseException

Description copied from class: AbstractUnitFormat

Parses a portion of the specified CharSequence from the specified position to produce a unit. If there is no unit to parse AbstractUnit.ONE is returned.

Specified by:

parse in interface javax.measure.format.UnitFormat

Specified by:

parse in class AbstractUnitFormat

Parameters:

csq - the CharSequence to parse.

cursor - the cursor holding the current parsing index.

Returns:

the unit parsed from the specified character sub-sequence.

Throws:

javax.measure.format.MeasurementParseException

parse

protected javax.measure.Unit<?> parse(CharSequence csq,
                                      int index)
                               throws IllegalArgumentException

Description copied from class: AbstractUnitFormat

Parses a portion of the specified CharSequence from the specified position to produce a unit. If there is no unit to parse AbstractUnit.ONE is returned.

Specified by:

parse in class AbstractUnitFormat

Parameters:

csq - the CharSequence to parse.

index - the current parsing index.

Returns:

the unit parsed from the specified character sub-sequence.

Throws:

IllegalArgumentException - if any problem occurs while parsing the specified character sequence (e.g. illegal syntax).

parse

public javax.measure.Unit<?> parse(CharSequence csq)
                            throws javax.measure.format.MeasurementParseException

Throws:

javax.measure.format.MeasurementParseException