mondrian.util

Class DigitList

java.lang.Object

mondrian.util.DigitList

final class DigitList
extends Object

DigitList handles the transcoding between numeric values and strings of characters. It only represents non-negative numbers. The division of labor between DigitList and DecimalFormat is that DigitList handles the radix 10 representation issues and numeric conversion, including rounding; DecimalFormat handles the locale-specific issues such as positive and negative representation, digit grouping, decimal point, currency, and so on.

A DigitList is a representation of a finite numeric value. DigitList objects do not represent NaN or infinite values. A DigitList value can be converted to a BigDecimal without loss of precision. Conversion to other numeric formats may involve loss of precision, depending on the specific value.

The DigitList representation consists of a string of characters, which are the digits radix 10, from '0' to '9'. It also has a base 10 exponent associated with it. The value represented by a DigitList object can be computed by mulitplying the fraction f, where 0 <= f < 1, derived by placing all the digits of the list to the right of the decimal point, by 10^exponent.

Version:

1.18 08/12/98

Author:

Mark Davis, Alan Liu

See Also:

Locale, Format, ChoiceFormat, MessageFormat

Field Summary

Fields

Modifier and Type	Field and Description
int	count
int	decimalAt These data members are intentionally public and can be set directly.
byte[]	digits
static int	MAX_LONG_DIGITS The maximum number of significant digits in an IEEE 754 double, that is, in a Java double.

Constructor Summary

Constructors

Constructor and Description
DigitList()

Method Summary

Methods

Modifier and Type	Method and Description
void	append(int digit) Appends digits to the list.
void	round(int maximumDigits) Round the representation to the given number of digits.
void	set(BigInteger source, int maximumDigits) Set the digit list to a representation of the given BigInteger value.
(package private) void	set(double source, int maximumDigits, boolean fixedPoint) Set the digit list to a representation of the given double value.
void	set(long source) Utility routine to set the value of the digit list from a long
void	set(long source, int maximumDigits) Set the digit list to a representation of the given long value.

Methods inherited from class java.lang.Object

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

Field Detail

MAX_LONG_DIGITS

public static final int MAX_LONG_DIGITS

The maximum number of significant digits in an IEEE 754 double, that is, in a Java double. This must not be increased, or garbage digits will be generated, and should not be decreased, or accuracy will be lost.

See Also:

Constant Field Values

decimalAt

public int decimalAt

These data members are intentionally public and can be set directly.

The value represented is given by placing the decimal point before digits[decimalAt]. If decimalAt is < 0, then leading zeros between the decimal point and the first nonzero digit are implied. If decimalAt is > count, then trailing zeros between the digits[count-1] and the decimal point are implied.

Equivalently, the represented value is given by f * 10^decimalAt. Here f is a value 0.1 ≤ f < 1 arrived at by placing the digits in Digits to the right of the decimal.

DigitList is normalized, so if it is non-zero, figits[0] is non-zero. We don't allow denormalized numbers because our exponent is effectively of unlimited magnitude. The count value contains the number of significant digits present in digits[].

Zero is represented by any DigitList with count == 0 or with each digits[i] for all i ≤ count == '0'.

count

public int count

digits

public byte[] digits

Constructor Detail

DigitList

DigitList()

Method Detail

append

public void append(int digit)

Appends digits to the list.

set

final void set(double source,
       int maximumDigits,
       boolean fixedPoint)

Set the digit list to a representation of the given double value. This method supports both fixed-point and exponential notation.

Parameters:

source - Value to be converted; must not be Inf, -Inf, Nan, or a value ≤ 0.

maximumDigits - The most fractional or total digits which should be converted.

fixedPoint - If true, then maximumDigits is the maximum fractional digits to be converted. If false, total digits.

round

public final void round(int maximumDigits)

Round the representation to the given number of digits.

Parameters:

maximumDigits - The maximum number of digits to be shown. Upon return, count will be less than or equal to maximumDigits. This now performs rounding when maximumDigits is 0, formerly it did not.

set

public final void set(long source)

Utility routine to set the value of the digit list from a long

set

public final void set(long source,
       int maximumDigits)

Set the digit list to a representation of the given long value.

Parameters:

source - Value to be converted; must be >= 0 or == Long.MIN_VALUE.

maximumDigits - The most digits which should be converted. If maximumDigits is lower than the number of significant digits in source, the representation will be rounded. Ignored if <= 0.

set

public final void set(BigInteger source,
       int maximumDigits)

Set the digit list to a representation of the given BigInteger value.

Parameters:

source - Value to be converted

maximumDigits - The most digits which should be converted. If maximumDigits is lower than the number of significant digits in source, the representation will be rounded. Ignored if <= 0.