Package org.apache.commons.imaging.common

Class RationalNumber

java.lang.Object

java.lang.Number

org.apache.commons.imaging.common.RationalNumber

All Implemented Interfaces:

java.io.Serializable

public class RationalNumber
extends java.lang.Number

Rational number, as used by the TIFF image format.

The TIFF format specifies two data types for rational numbers based on a pair of 32-bit integers. Rational is based on unsigned 32-bit integers and SRational is based on signed 32-bit integers. This treatment is problematic in Java because Java does not support unsigned types. To address this challenge, this class stores the numerator and divisor in long (64-bit) integers, applying masks as necessary for the unsigned type.

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private static class	RationalNumber.Option

Field Summary

Fields

Modifier and Type	Field	Description
long	divisor
long	numerator
private static long	serialVersionUID
static int	SHALLOW_SIZE
private static double	TOLERANCE
boolean	unsignedType

Constructor Summary

Constructors

Modifier	Constructor	Description
	RationalNumber(int numerator, int divisor)	Constructs an instance based on signed integers
	RationalNumber(int numerator, int divisor, boolean unsignedType)	Constructs an instance supports either signed or unsigned integers.
private	RationalNumber(long numerator, long divisor, boolean unsignedType)	A private constructor for methods such as negate() that create instances of this class using the content of the current instance.

Method Summary

Modifier and Type	Method	Description
double	doubleValue()
(package private) static RationalNumber	factoryMethod(long n, long d)
float	floatValue()
private static long	gcd(long a, long b)	Gets the greatest common divisor
int	intValue()
long	longValue()
RationalNumber	negate()	Negates the value of the RationalNumber.
java.lang.String	toDisplayString()
java.lang.String	toString()
static RationalNumber	valueOf(double value)	Calculate rational number using successive approximations.

Methods inherited from class java.lang.Number

byteValue, shortValue

Methods inherited from class java.lang.Object

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

Field Detail

serialVersionUID

private static final long serialVersionUID

See Also:

Constant Field Values

TOLERANCE

private static final double TOLERANCE

See Also:

Constant Field Values

SHALLOW_SIZE

public static final int SHALLOW_SIZE

See Also:

Constant Field Values

numerator

public final long numerator

divisor

public final long divisor

unsignedType

public final boolean unsignedType

Constructor Detail

RationalNumber

public RationalNumber(int numerator,
                      int divisor)

Constructs an instance based on signed integers

Parameters:

numerator - a 32-bit signed integer

divisor - a non-zero 32-bit signed integer

RationalNumber

public RationalNumber(int numerator,
                      int divisor,
                      boolean unsignedType)

Constructs an instance supports either signed or unsigned integers.

Parameters:

numerator - a numerator in the indicated form (signed or unsigned)

divisor - a non-zero divisor in the indicated form (signed or unsigned)

unsignedType - indicates whether the input values are to be treated as unsigned.

RationalNumber

private RationalNumber(long numerator,
                       long divisor,
                       boolean unsignedType)

A private constructor for methods such as negate() that create instances of this class using the content of the current instance.

Parameters:

numerator - a valid numerator

divisor - a valid denominator

unsignedType - indicates how numerator and divisor values are to be interpreted.

Method Detail

factoryMethod

static RationalNumber factoryMethod(long n,
                                    long d)

gcd

private static long gcd(long a,
                        long b)

Gets the greatest common divisor

valueOf

public static RationalNumber valueOf(double value)

Calculate rational number using successive approximations.

Parameters:

value - rational number double value

Returns:

the RationalNumber representation of the double value

doubleValue

public double doubleValue()

Specified by:

doubleValue in class java.lang.Number

floatValue

public float floatValue()

Specified by:

floatValue in class java.lang.Number

intValue

public int intValue()

Specified by:

intValue in class java.lang.Number

longValue

public long longValue()

Specified by:

longValue in class java.lang.Number

negate

public RationalNumber negate()

Negates the value of the RationalNumber. If the numerator of this instance has its high-order bit set, then its value is too large to be treated as a Java 32-bit signed integer. In such a case, the only way that a RationalNumber instance can be negated is to divide both terms by a common divisor, if a non-zero common divisor exists. However, if no such divisor exists, there is no numerically correct way to perform the negation. When a negation cannot be performed correctly, this method throws an unchecked exception.

Returns:

a valid instance with a negated value.

toDisplayString

public java.lang.String toDisplayString()

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object