net.sf.saxon.value

Class NumericValue

public abstract class NumericValue extends AtomicValue implements Comparable

NumericValue is an abstract superclass for IntegerValue, DecimalValue, FloatValue, and DoubleValue
Method Summary
abstract NumericValuearithmetic(int operator, NumericValue other, XPathContext context)
Perform a binary arithmetic operation
abstract NumericValueceiling()
Implement the XPath ceiling() function
intcompareTo(Object other)
Compare the value to another numeric value
booleanequals(Object other)
The equals() function compares numeric equality among integers, decimals, floats, doubles, and their subtypes
abstract NumericValuefloor()
Implement the XPath floor() function
doublegetDoubleValue()
Get the numeric value as a double
abstract inthashCode()
hashCode() must be the same for two values that are equal.
static booleanisInteger(AtomicValue value)
Test whether the value is an integer (an instance of a subtype of xs:integer)
booleanisNaN()
Test whether the value is the double/float value NaN
abstract booleanisWholeNumber()
Determine whether the value is a whole number, that is, whether it compares equal to some integer
longlongValue()
Return the numeric value as a Java long.
abstract NumericValuenegate()
Change the sign of the number
static NumericValueparseNumber(String in)
Get a numeric value by parsing a string; the type of numeric value depends on the lexical form of the string, following the rules for XPath numeric literals.
static ItemTypepromote(ItemType v1, ItemType v2, TypeHierarchy typeHierarchy)
Identify lowest common supertype of two numeric values for promotion purposes
abstract NumericValueround()
Implement the XPath round() function
abstract NumericValueroundToHalfEven(int scale)
Implement the XPath 2.0 round-to-half-even() function
abstract doublesignum()
Determine whether the value is negative, zero, or positive
StringtoString()
Produce a string representation of the value

Method Detail

arithmetic

public abstract NumericValue arithmetic(int operator, NumericValue other, XPathContext context)
Perform a binary arithmetic operation

Parameters: operator the binary arithmetic operation to be performed. Uses the constants defined in the Tokenizer class other the other operand

Returns: the result of the arithmetic operation

Throws: XPathException if an arithmetic error occurs

See Also: Tokenizer

ceiling

public abstract NumericValue ceiling()
Implement the XPath ceiling() function

Returns: a value, of the same type as that supplied, rounded towards plus infinity

compareTo

public int compareTo(Object other)
Compare the value to another numeric value

Parameters: other The other numeric value

Returns: -1 if this one is the lower, 0 if they are numerically equal, +1 if this one is the higher.

Throws: ClassCastException if the other value is not a NumericValue (the parameter is declared as Object to satisfy the Comparable interface)

equals

public final boolean equals(Object other)
The equals() function compares numeric equality among integers, decimals, floats, doubles, and their subtypes

Parameters: other the value to be compared with this one

Returns: true if the two values are numerically equal

floor

public abstract NumericValue floor()
Implement the XPath floor() function

Returns: a value, of the same type as that supplied, rounded towards minus infinity

getDoubleValue

public double getDoubleValue()
Get the numeric value as a double

Returns: A double representing this numeric value; NaN if it cannot be converted

hashCode

public abstract int hashCode()
hashCode() must be the same for two values that are equal. One way to ensure this is to convert the value to a double, and take the hashCode of the double. But this is expensive in the common case where we are comparing integers. So we adopt the rule: for values that are in the range of a Java Integer, we use the int value as the hashcode. For values outside that range, we convert to a double and take the hashCode of the double. This method needs to have a compatible implementation in each subclass.

Returns: the hash code of the numeric value

isInteger

public static boolean isInteger(AtomicValue value)
Test whether the value is an integer (an instance of a subtype of xs:integer)

isNaN

public boolean isNaN()
Test whether the value is the double/float value NaN

isWholeNumber

public abstract boolean isWholeNumber()
Determine whether the value is a whole number, that is, whether it compares equal to some integer

Returns: true if the value is a whole number

longValue

public long longValue()
Return the numeric value as a Java long.

Returns: the numeric value as a Java long. This performs truncation towards zero.

Throws: net.sf.saxon.trans.XPathException if the value cannot be converted

negate

public abstract NumericValue negate()
Change the sign of the number

Returns: a value, of the same type as the original, with its sign inverted

parseNumber

public static NumericValue parseNumber(String in)
Get a numeric value by parsing a string; the type of numeric value depends on the lexical form of the string, following the rules for XPath numeric literals.

Parameters: in the input string

Returns: a NumericValue representing the value of the string. Returns Double.NaN if the value cannot be parsed as a string.

promote

public static ItemType promote(ItemType v1, ItemType v2, TypeHierarchy typeHierarchy)
Identify lowest common supertype of two numeric values for promotion purposes

Parameters: v1 the item type of the first operand v2 the item type of the second operand typeHierarchy

Returns: the item type that should be used for arithmetic between operands of the two specified item types

round

public abstract NumericValue round()
Implement the XPath round() function

Returns: a value, of the same type as that supplied, rounded towards the nearest whole number (0.5 rounded up)

roundToHalfEven

public abstract NumericValue roundToHalfEven(int scale)
Implement the XPath 2.0 round-to-half-even() function

Parameters: scale the decimal position for rounding: e.g. 2 rounds to a multiple of 0.01, while -2 rounds to a multiple of 100

Returns: a value, of the same type as the original, rounded towards the nearest multiple of 10**(-scale), with rounding towards the nearest even number if two values are equally near

signum

public abstract double signum()
Determine whether the value is negative, zero, or positive

Returns: -1 if negative, 0 if zero (including negative zero), +1 if positive, NaN if NaN

toString

public String toString()
Produce a string representation of the value

Returns: The result of casting the number to a string