net.sf.saxon.value
Class NumericValue

java.lang.Object
  net.sf.saxon.value.Value
      net.sf.saxon.value.AtomicValue
          net.sf.saxon.value.NumericValue

All Implemented Interfaces:

Serializable, Comparable, PullEvent, SequenceIterable, GroundedValue, Item, ValueRepresentation, ConversionResult

Direct Known Subclasses:

DecimalValue, DoubleValue, FloatValue, IntegerValue

public abstract class NumericValue
extends AtomicValue
implements Comparable

NumericValue is an abstract superclass for IntegerValue, DecimalValue, FloatValue, and DoubleValue

See Also:

Serialized Form

Field Summary

Fields inherited from class net.sf.saxon.value.Value

EMPTY_CLASS_ARRAY, INDETERMINATE_ORDERING

Fields inherited from interface net.sf.saxon.om.ValueRepresentation

EMPTY_VALUE_ARRAY

Fields inherited from interface net.sf.saxon.om.ValueRepresentation

EMPTY_VALUE_ARRAY

Constructor Summary

NumericValue()

Method Summary

abstract NumericValue	ceiling() Implement the XPath ceiling() function
abstract int	compareTo(long other) Compare the value to a long
int	compareTo(Object other) Compare the value to another numeric value
boolean	equals(Object other) The equals() function compares numeric equality among integers, decimals, floats, doubles, and their subtypes
abstract NumericValue	floor() Implement the XPath floor() function
BigDecimal	getDecimalValue() Get the numeric value converted to a decimal
double	getDoubleValue() Get the numeric value as a double
float	getFloatValue() Get the numeric value converted to a float
Object	getXPathComparable(boolean ordered, StringCollator collator, XPathContext context) Get a Comparable value that implements the XPath ordering comparison semantics for this value.
abstract int	hashCode() hashCode() must be the same for two values that are equal.
static boolean	isInteger(AtomicValue value) Test whether a value is an integer (an instance of a subtype of xs:integer)
abstract boolean	isWholeNumber() Determine whether the value is a whole number, that is, whether it compares equal to some integer
long	longValue() Return the numeric value as a Java long.
abstract NumericValue	negate() Change the sign of the number
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.
static ItemType	promote(ItemType v1, ItemType v2, TypeHierarchy typeHierarchy) Identify lowest common supertype of two numeric values for promotion purposes
abstract NumericValue	round() Implement the XPath round() function
abstract NumericValue	roundHalfToEven(int scale) Implement the XPath 2.0 round-half-to-even() function
abstract double	signum() Determine whether the value is negative, zero, or positive
String	toString() Produce a string representation of the value

Methods inherited from class net.sf.saxon.value.AtomicValue

asAtomic, checkPermittedContents, convert, convert, copyAsSubType, effectiveBooleanValue, getCardinality, getComponent, getItemType, getLength, getPrimitiveType, getSchemaComparable, getStringValue, getStringValueCS, getTypedValue, getTypeLabel, isNaN, itemAt, iterate, process, setTypeLabel, subsequence

Methods inherited from class net.sf.saxon.value.Value

asItem, asItem, asIterator, asValue, convertJavaObjectToXPath, convertToJava, convertToJava, fromItem, getCanonicalLexicalRepresentation, getIterator, iterate, makeQNameValue, reduce, stringToNumber

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

NumericValue

public NumericValue()

Method Detail

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.

getDoubleValue

public double getDoubleValue()

Get the numeric value as a double

Returns:

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

getFloatValue

public float getFloatValue()

Get the numeric value converted to a float

Returns:

a float representing this numeric value; NaN if it cannot be converted

getDecimalValue

public BigDecimal getDecimalValue()
                           throws XPathException

Get the numeric value converted to a decimal

Returns:

a decimal representing this numeric value;

Throws:

XPathException - if the value cannot be converted, for example if it is NaN or infinite

isInteger

public static boolean isInteger(AtomicValue value)

Test whether a value is an integer (an instance of a subtype of xs:integer)

Parameters:

value - the value being tested

Returns:

true if the value is an instance of xs:integer or a type derived therefrom

longValue

public long longValue()
               throws XPathException

Return the numeric value as a Java long.

Returns:

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

Throws:

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

floor

public abstract NumericValue floor()

Implement the XPath floor() function

Returns:

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

ceiling

public abstract NumericValue ceiling()

Implement the XPath ceiling() function

Returns:

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

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)

roundHalfToEven

public abstract NumericValue roundHalfToEven(int scale)

Implement the XPath 2.0 round-half-to-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

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

getXPathComparable

public Object getXPathComparable(boolean ordered,
                                 StringCollator collator,
                                 XPathContext context)

Get a Comparable value that implements the XPath ordering comparison semantics for this value. Returns null if the value is not comparable according to XPath rules. The default implementation returns null. This is overridden for types that allow ordered comparisons in XPath: numeric, boolean, string, date, time, dateTime, yearMonthDuration, dayTimeDuration, and anyURI.

Specified by:

getXPathComparable in class AtomicValue

Parameters:

ordered -

collator -

context -

Returns:

an Object whose equals() and hashCode() methods implement the XPath comparison semantics with respect to this atomic value. If ordered is specified, the result will either be null if no ordering is defined, or will be a Comparable

compareTo

public int compareTo(Object other)

Compare the value to another numeric value

Specified by:

compareTo in interface Comparable

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, or if either value is NaN. Where NaN values are involved, they should be handled by the caller before invoking this method.

Throws:

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

compareTo

public abstract int compareTo(long other)

Compare the value to a long

Parameters:

other - the value to be compared with

Returns:

-1 if this is less, 0 if this is equal, +1 if this is greater or if this is NaN

equals

public final boolean equals(Object other)

The equals() function compares numeric equality among integers, decimals, floats, doubles, and their subtypes

Specified by:

equals in class AtomicValue

Parameters:

other - the value to be compared with this one

Returns:

true if the two values are numerically equal

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 - the type hierarchy cache

Returns:

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

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.

Overrides:

hashCode in class Object

Returns:

the hash code of the numeric value

toString

public String toString()

Produce a string representation of the value

Overrides:

toString in class AtomicValue

Returns:

The result of casting the number to a string